65FR38182 Elimination of the Requirement for Noncombustible Fire Barrier Penetration Seal Materials and Other Minor Changes, Part 1/2
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[Federal Register: June 20, 2000 (Volume 65, Number 119)]
[Rules and Regulations]
[Page 38182-38191]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
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NUCLEAR REGULATORY COMMISSION
10 CFR Part 50
RIN 3150-AG22
Elimination of the Requirement for Noncombustible Fire Barrier
Penetration Seal Materials and Other Minor Changes
AGENCY: Nuclear Regulatory Commission.
ACTION: Final rule.
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SUMMARY: The Nuclear Regulatory Commission (NRC) is amending its fire
protection regulations to remove the requirement that fire barrier
penetration seal materials be noncombustible, and to make other minor
changes. The final rule removes a requirement that has a negligible
contribution to safety and includes editorial changes designed to meet
the intent of the Presidential memorandum dated June 1, 1998, entitled,
``Plain Language in Government Writing.''
EFFECTIVE DATE: July 20, 2000.
FOR FURTHER INFORMATION CONTACT: Daniele Oudinot, Office of Nuclear
Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC
20555-0001, telephone 301-415-3731; e-mail D...@nrc.gov.
SUPPLEMENTARY INFORMATION:
I. Background
The NRC conducted a technical assessment of fire barrier
penetration seals. The NRC documented the results of its assessment in
SECY-96-146, ``Technical Assessment of Fire Barrier Penetration Seals
in Nuclear Power Plants,'' July 1, 1996; in NUREG-1552, ``Fire Barrier
Penetration Seals in Nuclear Power Plants,'' July 1996; and in NUREG-
1552, Supplement 1, January 1999. On the basis of its findings, the NRC
concluded that the noncombustibility criterion for penetration seal
materials that is specified in the NRC fire protection regulation and
review guidance had a negligible contribution to safety, and
recommended that this noncombustibility criterion be deleted. Copies of
NUREG-1552 and NUREG-1552, Supplement 1, may be purchased from the
Superintendent of Documents, U.S. Government Printing Office, P.O. Box
37082, Washington, DC 20402-9328. Copies are also available from the
National Technical Information Service, 5285 Port Royal Road,
Springfield, VA 22161. A copy of each document is also available for
inspection and/or copying at the NRC Public Document Room, 2120 L
Street, NW. (Lower Level), Washington, DC. NUREG-1552, Supplement 1, is
also available through the Technical Reports area of the NRC Reference
Library accessed through the NRC Website: http://www.nrc.gov/NRC/
NUREGS/index.html.
II. Analysis of Public Comments and Staff Response
The proposed rule was published for public comment in the Federal
Register on August 18, 1999 (64 FR 44860). The comment period ended on
November 1, 1999. The NRC received eight comment letters. Six
commenters supported the proposed amendment; two commenters objected to
the changes. This section discusses the comments received, how the NRC
staff was able to incorporate some comments into the final rule and, if
not, why a comment was not accepted. This section addresses all
comments, but specific commenters are not identified.
A commenter suggested that footnote 1 to Section I, ``Introduction
and Scope,'' of Appendix R to 10 CFR Part 50, be deleted because its
wording is identical to footnote 4 to Sec. 50. 48(b). This commenter
stated that the basis for deleting footnote 4 to Sec. 50.48 also
applies to footnote 1 to Section I of Appendix R. The NRC agrees with
this comment and footnote 1 to Section I of Appendix R is deleted.
One of the commenters who endorsed the proposed rule stated that,
in particular, (1) There are no reports of fire that have challenged
the ability of fire-rated penetration seals to confine a fire; (2)
numerous fire endurance tests have confirmed the fire-resistive
capabilities of the penetration seal materials, designs, and
configurations installed in nuclear power plants; and (3) if
penetration seals are properly designed, installed, and maintained,
there is reasonable assurance that they will provide the fire-resistive
integrity of the fire barriers in which they are installed, and confine
a fire to its area of origin.
A commenter objected to the rule change, but did not identify any
specific technical or safety information for NRC staff consideration.
Therefore, the comment did not result in changes to the rule.
One commenter provided multiple comments in opposition to the
proposed rule. Each of these comments are discussed below. None of the
comments resulted in any changes from the proposed rule.
1. Comment. The non-combustibility requirement for fire seals is
key in providing a high level of confidence in the operability
determination for a fire seal.
Response. The Commission disagrees. 10 CFR Part 50, Appendix A,
General Design Criteria (GDC), Criterion 3--Fire Protection states:
``Noncombustible and heat resistant materials shall be used wherever
practical throughout the unit. * * *'' Thus, the Commission's most
fundamental requirements with respect to fire protection do not mandate
the exclusive use of noncombustible materials. The Commission's
implementing requirements on fire protection in 10 CFR 50.48 and 10 CFR
Part 50, Appendix R, require the use of fire barriers that meet 1-hour
or 3-hour fire ratings; while the current regulation requires the use
of noncombustible materials it is also clear that the 1-hour and 3-hour
ratings can be achieved with the use of properly tested, rated and
qualified material that is ``combustible.'' Penetration seals used as a
part of the rated fire barrier assembly are required to meet the
acceptance criteria of Nationally Recognized Testing Standards that are
specifically designed to test these components. Examples of these
standards include American Society for Testing and Materials (ASTM) E-
814, ``Standard Test Method for Fire Tests of Through-Penetration Fire
Stops,'' and Institute of Electrical and Electronics Engineers (IEEE)
634, ``Standard Cable Penetration Fire Stop Qualification Test.'' These
nationally recognized testing standards do not require the penetration
seal material to be noncombustible, but rather focus on the penetration
seals ability to prevent flame travel through the opening and limit the
heat transfer through the penetration seal assembly by measuring the
cold-side temperature. As such, ``noncombustibility,'' as defined in
ASTM-136, ``Standard Test Method for Behavior of Materials in a
Vertical Tube Furnace at 750 deg.C,'' is not a necessary requirement
for an adequate fire barrier or a penetration seal that is part of this
barrier. Penetration seal assemblies, when properly tested, qualified,
and installed, meet this requirement as a fire (heat) resistant
material. In fire protection engineering design, this can be thought of
as analogous to the National Fire Protection Association (NFPA) Life
Safety Code, NFPA 101,
[[Page 38183]]
which allows certain wooden doors to be used as 20-minute fire
protection-rated doors. (See NFPA 101, Section 6-2.3.2.3.2.) The NFPA
Code recognizes that even though the wooden door assembly is
unquestionably combustible, as long as that fire door assembly can
provide the required level of protection (20 minutes in this example)
the wooden door assembly is acceptable. In sum, the current Appendix R
requirement for noncombustible fire barrier penetration seals is not an
inherent part of the NRC's overall regulatory approach on fire
protection, and is not necessary to provide reasonable assurance of
adequate protection against fire spread in nuclear power plants.
2. Comment. The NRC has not analyzed the risk associated with the
use of combustible fire seal material as it provides a fuel supported
pathway or ``wick'' for flame and hot gas to burn through wall
penetrations into adjacent fire zones that contain vital safety
systems, structures or components.
Response. As discussed in NUREG-1552 and its supplement, the NRC
has evaluated fire barrier penetration seals and concluded that
properly tested, configured, installed, and maintained penetration seal
assemblies will not provide a fuel supported pathway or ``wick'' for
flame and hot gas to burn through wall penetrations. Hundreds of fire
endurance qualification tests have been performed by materials
manufacturers, installation contractors, test laboratories, research
organizations, licensees, and others. These qualification tests
involved a wide variety of penetration seal designs and materials, in
configurations which are found at nuclear power plants, including the
actual cables that run through the fire barrier penetration seal. These
tests also maximize the fire severity by subjecting the penetration
seals to a rapidly rising temperature in a relatively small and
confined space. Note that with few exceptions, nuclear power plant fire
loads are not great enough to produce a fire approaching the severity
of the Standard Time/Temperature test curve. In the unlikely event that
a large fire exposes a qualified combustible or noncombustible
penetration seal to high temperatures for an extended period of time,
the seal will perform as rated. For the case of a silicone-based
material, the silicone will ablate by design and be replaced with char
or ash. The silicone foam material is sacrificial by design in
preserving the integrity of the fire barrier. This sacrificial behavior
and charing has been observed during full-scale qualification fire
endurance tests of a wide variety of silicone-based penetration seal
configurations. Other combustible penetration seal materials have also
been qualified. For example, Minnesota Mining and Manufacturing Company
(3M) has over 25 years of experience with combustible penetration seal
designs using their intumescent materials (caulks, putty, wrap strips,
and composite sheets). The intumescent material swells when heated,
which causes the seal to expand and protect the penetration.
Underwriters Laboratories, Inc. (UL), has qualified dozens of
combustible penetration seal designs and lists and classifies these
designs in a full volume of their Fire Resistance Directory (Volume 2).
The NRC concludes that these tests have demonstrated that combustible,
limited combustible or noncombustible penetration seals can provide the
necessary fire resistance and provide reasonable assurance that a fire
will not spread from one side of the fire barrier to the other side of
the barrier within the 1- or 3-hour time period required by the NRC.
3. Comment. The NRC's technical assessment does not offer any
evaluation or analysis regarding the contribution to severe accident
risk evolving from a quick burn-through of fire seals resulting from
the use of combustible penetration sealant material and other generic
problems widely experienced with the Dow Corning product.
Response. As stated above, a large body of fire test results have
proven the capabilities and effectiveness of penetration seals in
maintaining the fire-resistive integrity of the barriers in which they
are installed, typically for 1 or 3 hours, which precludes a quick
burn-through scenario, i.e., if the penetration seal assembly has
passed the testing criteria to be rated, it could not experience a
``quick burn-through''. Further, the nature of combustible penetration
seal materials and the limited air supply in penetration seals preclude
a ``quick burn-through,'' and an analysis of the contribution to severe
accident risk evolving from a quick burn-through of fire seals
resulting from the use of combustible penetration sealant material is
not relevant. For instance, silicone-based penetration seal materials
are relatively difficult to ignite and ablate slowly at a rate of about
3 inches per hour when exposed to the Standard Time/Temperature fire
curve of ASTM E-119.
Fire barrier penetration seals are not considered in the assessment
of postulated fire scenarios that are the major contributors to core
damage for most plants, because the major contributors are those in
which the redundant divisions of post-fire safe-shutdown components and
systems are located in the fire affected area. Scenarios involving the
spread of fire from one area of a plant to another and evolving to core
damage (scenarios that could potentially involve penetration seals) are
also of low frequency. It is the NRC's judgment that considering the
probability of failure of a plant's passive fire barrier penetration
seals would not significantly alter the overall contribution of fire
risk to the plant's total calculated core damage frequency.
4. Comment. Given the combustibility of the silicone material, the
industry has also widely documented improperly installed seals (less
than sufficient sealant material, varying size voids created by
problematic installation procedures and cracks). By providing for the
acceptance of combustible penetration seals, the NRC is reducing the
level of defense-in-depth without fully analyzing the risks associated
with accelerated burn-through of seals from the combination of these
widely documented factors.
Response. The NRC disagrees with the commenter's implication that
there are widespread and numerous instances of improperly-installed
silicone fire barrier seals. First, while plant-specific deficiencies
of fire barrier penetration seals have been and will likely continue to
be found, they have been isolated and not tied to any installation
problems generic to this material. Installation deficiencies that have
been identified to date have been or are in the process of being
corrected by licensees.
Second, the NRC disagrees with the commenter's apparent argument
that combustible fire seals that meet the NRC's 1- and 3-hour fire
rating significantly decreases the safety of a nuclear power plant as
compared to fire seals which are ``noncombustible'' as defined by ASTM
E-136. Fire seals are one passive sub-component of fire protection
provided by the defense-in-depth concept, the others being fire
prevention, detection, suppression and plant-design features. As
discussed in the response to Comment 2, the NRC also believes that it
is highly unlikely that fire barriers in a nuclear power plant would be
exposed to fires of sufficient temperature and duration such that the
silicone fire seals that fail before their rated 1- or 3-hours. Thus,
consideration of the probability of failure of properly-qualified
penetration seals that meet the NRC's requirements for 1- or 3-hour
protection would not significantly alter the overall contribution of
fire risk to the plant's total calculated core damage frequency.
[[Page 38184]]
Finally, the practical benefits of the silicone-based penetration seal
materials (e.g., easy installation, compatibility around safety-related
cables, and reasonable cost) far outweigh concerns regarding material
combustibility. Thus, the NRC concludes that properly qualified fire
barriers will provide reasonable assurance of adequate protection to
public health and safety.
5. Comment. The NRC does not offer any analysis and evaluation of
how a combustible penetration sealant could also harbor a fire as it
moves through a penetration seal. The fire could leave a protective
barrier of insulating ash in its trail making it difficult to identify,
locate and extinguish. Accordingly, it is inappropriate to move forward
with this rule change without analysis on the quick burn-through of
seals under the above stated conditions.
Response. A properly designed, tested, and installed penetration
seal will maintain the fire resistive integrity of the wall/ceiling/
floor assembly in which it is installed. During this time, automatic
and/or manual fire suppression activities will be used to control and
extinguish the fire. After the fire is extinguished, standard fire
fighting procedures would require that the fire brigade perform the
``overhaul'' firefighting function of ensuring all combustibles have
been extinguished. During this firefighting, if the fire brigade were
to identify ash or swelled material in a penetration seal, procedures
would require that the fire brigade take appropriate action either to
identify whether the seal is continuing to combust (by removal), or to
promptly implement extinguishing activities. This is a standard
firefighting operation to check for any possible fire extension.
Therefore, the NRC concludes that it is not inordinately difficult to
identify and extinguish fires in combustible fire barrier penetration
seals.
6. Comment. The basic premise of the NRC rule change fails to
address industry experience in properly bounding fire tests for the
myriad of fire seal configurations deployed throughout nuclear power
stations. In one case, the licensee improperly used a single test to
bound 2000 fire barrier penetration seals in many different fire seal
configurations. This omission does not lend to the credibility of the
agency's argument. Such evidence documents improperly tested seal
configurations.
Response. The Browns Ferry fire of March 22, 1975, demonstrated the
weakness in penetration seals to the nuclear and general building
industry. After the fire, specific testing methods were developed by
nationally recognized testing organizations to test and qualify
penetration seals. The American Society for Testing and Materials
(ASTM) first issued their standard E-814, ``Standard Test Method for
Fire Tests of Through-Penetration Fire Stops,'' in 1981. The Institute
of Electrical and Electronics Engineers (IEEE) first issued their
standard IEEE 634, ``Standard Cable Penetration Fire Stop Qualification
Test,'' in 1978. In regard to the commenter's assertions regarding ``a
single test to bound 2000 fire barrier penetration seals * * *,'' the
first penetration seal fire tests were often used to bound numerous
configurations. This issue of bounding fire tests was addressed in
Information Notice (IN) 88-04, ``Inadequate qualification and
documentation of fire barrier penetration seals,'' dated February 5,
1988. Since that time, decades of experience with the test standards by
the nuclear and general building industries have provided adequate
assurance that such standards are appropriate for qualifying fire
barrier penetration seals. Hundreds of qualification-type fire
endurance tests of a wide variety of penetration seal designs and
materials have been performed by material manufacturers, installation
contractors, test laboratories, research organizations, licensee, and
others. Underwriters Laboratories, Inc. (UL) alone publishes a complete
volume of Listed and Classified rated through-penetration fire stop
systems. Additionally, the NRC staff has observed fire endurance tests
of fire barrier penetration seals, and reviewed fire test reports
during licensing reviews and inspections. On the basis of these
eyewitness accounts and reviews, the NRC staff has concluded that fire
endurance tests have established the fire-resistive capabilities of
numerous penetration seal materials, designs, and configurations as
installed in the nuclear power plants. The NRC staff provided guidance
on the bounding of plant-installed configurations with tested
configurations in Generic Letter 86-10, ``Implementation of Fire
Protection Requirements,'' dated April 24, 1986. Subsequently, the
industry used this guidance in inspecting plant designs. As licensees
identified potential penetration seal issues, the staff informed the
industry through numerous INs, including: (1) IN 88-04, and Supplement
1, dated August 9, 1988; (2) IN 88-56, ``Potential Problems with
Silicone Foam Fire Barrier Penetration Seals,'' dated August 4, 1988;
(3) IN 94-28, ``Potential Problems with Fire-Barrier Penetration
Seals,'' dated April 5, 1994; and (4) IN 97-70, ``Potential Problems
with Fire Barrier Penetration Seals,'' dated September 19, 1997. These
potential problems were brought forward by licensee inspections and NRC
staff observed weaknesses discovered during some of its inspections.
7. Comment. The basic premise of the NRC rule change fails to take
into account ongoing industry-wide discovery of insufficient material
fill, large voids and cracking in seals as the result of the
problematic installation of the silicone foam penetration seal material
in the field. In numerous cases, licensees have reported universal fire
seal installation problems involving the silicone foam material. Such
evidence documents improperly installed silicone-based penetration
seals. The NRC also fails to take into account that licensees are using
the same problematic material to replace inoperable fire seals. Given
these recurring and what appears to be ongoing failures, the NRC does
not offer any method for determining how it is achieving properly
tested, configured, installed and maintained silicone-based penetration
seals. Given the apparent lack of reasonable assurance that fire
barrier seals are adequately inspected to determine that they have been
properly tested, configured, installed and maintained, it is
inappropriate to reduce the fire protection standard by removing the
non-combustibility standard. Similarly, it is inappropriate to maintain
a policy of enforcement discretion for the same noncombustibility
standard.
Response. The NRC disagrees with the commenter's implicit argument
that historical problems with installation of silicone fire barrier
penetration seals have not been rectified, and, as a result, the
Appendix R non-combustibility requirement should be retained.
The NRC disagrees with the commenter's assertion that improper
installation and maintenance of fire barrier penetration seals is a
reasonable basis for retaining the current noncombustibility
requirement. First, proper installation of fire barrier penetration
seals is necessary in order for the seals to perform their intended
safety function, regardless of whether the seals are made of
combustible or noncombustible materials. Licensees must have
appropriate procedures for installation of Appendix R-required fire
barrier penetration seals and implement corrective action if improperly
installed seals are discovered, regardless of the combustibility of the
fire barrier penetration seal material. Thus, while improperly
installed fire barrier penetration seals raise valid concerns with
respect to their functionality, these concerns are not relevant to the
issue of
[[Page 38185]]
the need for a noncombustibility requirement.
Second, the NRC disagrees with the commenter's implicit argument
that there are widespread problems with the installation, inspection,
and maintenance of fire barrier penetration seals that remain
uncorrected. While there have been historical problems with the
installation of silicone fire barrier penetration seals, the NRC has
taken a series of regulatory actions in response to instances of
improper fire barrier penetration seal installation. These actions
include the issuance of the information notices discussed above to
alert nuclear power plant licensees of potential problems with silicone
fire barrier penetration seal installation and inspection, changes to
the NRC resident inspector inspection program to include fire barrier
penetration seals as part of the NRC's inspection program, and
continued NRC review and oversight of licensees' corrective actions.
The NRC has confirmed that licensees have taken appropriate action to
identify and correct improperly installed silicone-based fire barrier
penetration's seals, as discussed in NUREG-1522 and its supplement.
Based upon NRC inspections and audits, the NRC believes that licensees
and vendors understand the fire-resistive capabilities and limitations
of the penetration seal materials, and that existing licensee and
vendor seal installation programs are adequate to prevent potential
penetration seal installation problems. Potential penetration seal
problems are understood; industry standards are available and licensees
are complying with them. In regard to installation, maintenance, and
in-service inspection, the NRC's comprehensive reassessment of fire
barrier penetration seals included the review of procedures,
specifications, and training programs for installation, surveillance,
maintenance, and repair of penetration seals at both nuclear power
plants and the facilities where seals are manufactured. Overall, the
NRC concluded that licensees and vendors are aware of the importance of
proper design, installation, surveillance, maintenance, and repair of
penetration seals, including training of installers and inspectors.
Therefore, based on inspections and review of the licensees' corrective
action programs, the NRC concludes that historical problems with the
installation of silicone-based fire barrier penetration seals have been
corrected. Many plants include fire barrier penetration seals that are
required by Appendix R in their Maintenance Rule's requirements program
(10 CFR 50.65). This requires monitoring of the performance or
condition of relevant structures, systems and components (SSCs) unless
there is a continuing basis for concluding that the performance or
condition of the SSCs is being effectively controlled. This provides
additional regulatory assurance that fire barrier penetration seals are
being properly installed, inspected, and maintained. For these reasons,
the NRC concludes that historical problems with fire barrier
penetration seal installation and inspection does not provide an
appropriate basis for retaining the current noncombustibility
requirement in Appendix R.
8. Comment. Visual industry reliance upon walk-downs of fire
barrier penetration seals installed in walls, ceilings and floors, in
many cases behind a series of obstacles, is not sufficient in
determining the reliability and operability of a silicone foam fire
barrier penetration seal. Non-destructive examination of installed
seals (e.g., ultrasound techniques) can provide a greater measure of
confidence in determining if a seal has been properly installed.
Response. The NRC believes that existing inspection techniques
developed by the manufacturers of silicone fire barrier penetration
seals for evaluating the adequacy of installation of seals are
adequate. The vendor requirements for physical parameters for the
installation of seals include attributes such as density of the mixed
material, cell structure, texture, and color. These are the same
parameters used in the construction of the penetration seals for
testing and, as such, ensure that the seals installed in the plant are
representative of those qualified during testing. The installed
penetration seals are passive fire barriers and remain unchanged after
proper installation. The commenter did not provide any credible
information showing that the manufacturer-developed installation
inspection methodology (which may include visual examinations) is
inadequate to detect improper installation. In the absence of such
information, the NRC does not believe that any consideration should be
given to requiring non-destructive examination, which is outside of the
scope of the rule change. When the NRC discovers a problem with
penetration seals, such as can occur in the area of surveillances, the
NRC alerts licensees and advises them to evaluate whether the potential
problem exists at their plants. Licensees typically evaluate this
information for applicability to their plants as a part of their
Nuclear Experience Review Program and take corrective actions when
necessary. For example, fire penetration seal surveillance problems
were discussed in IN 88-56 which examines in detail visual inspection
information regarding voids, gaps, and splits in the material.
9. Comment. Because of the evidence of recurring non-compliance
with testing, configuration, installation and maintenance, retaining
and enforcing the non-combustibility standard is an essential component
in establishing confidence in fire barrier penetration seal operability
at nuclear power stations.
Response. As discussed above, the NRC does not agree that there are
recurring, generic problems with fire barrier penetration seal
qualification, configuration and installation throughout the nuclear
power plant industry. The NRC believes that the proper amount of
attention is being provided by licensees and will be provided for in
the future. Additionally, to prevent any possible deficiencies in the
penetration seal program, the NRC will continue to provide regulatory
oversight.
10. Comment. In making the claim that combustible materials are
already used in nuclear power stations, NRC attempts to circumlocate
(sic.) the significant safety issue on how combustible cable jacketing
installed through a penetration surrounded in a combustible fire
barrier material with additional documented problems can contribute to
an accelerated burn through thus failing as a rated fire barrier.
Response. As discussed in the response to Comment 2, the fire
endurance tests for qualifying fire barrier penetration seals were
conducted using the cable which would be used in the actual plant
configurations. Thus, the contribution of the cable jacketing to
combustion of the fire barrier penetration seal was an inherent part of
the fire endurance qualification tests.
11. Comment. NRC provides no reference to what degree staff and
Commission went to arrive at the determination that no technical
argument exists for the fire barrier penetration seals non-combustible
materials requirement.
Response. The primary documents reviewed by the NRC in attempting
to identify the basis for the current noncombustibility requirement
were the statements of consideration for the proposed and final Fire
Protection rules, May 29, 1980; 45 FR 36082, and November 19, 1980; 45
FR 76608 and the Commission papers that led to these proposed and final
rules. The primary
[[Page 38186]]
technical documents and rationales for the Commission's determination
that no technical basis exists for the noncombustibility requirement
are contained in NUREG-1552 and Supplement 1 to that document.
III. Summary of Changes
This final rule amends Section III.M in Appendix R to 10 CFR Part
50 (Appendix R), removes footnotes 3 and 4 from Sec. 50.48, removes
footnote 1 from Section I in Appendix R, removes Sec. 50.48 (c), (d),
and (e), corrects a grammatical error in footnote 2 to Section III.G. 3
in Appendix R, and makes editorial changes.
1. In Appendix R, Section III.M, the words ``shall utilize only
noncombustible materials and * * *'' are removed.
The technical basis for removing the noncombustibility requirement
for fire barrier penetration seal materials is documented in NUREG-1552
and NUREG-1552, Supplement 1. A summary of the technical basis for this
action follows.
NRC requirements and guidelines for penetration seals appear in a
number of documents. In 1971, the NRC promulgated General Design
Criterion (GDC) 3, ``Fire protection,'' and subsequently developed
specific guidance for implementing GDC 3; Branch Technical Position
(BTP) Auxiliary Power Conversion Systems Branch (APCSB) 9.5-1,
``Guidelines for Fire Protection for Nuclear Power Plants,'' May 1,
1976; and Appendix A to BTP APCSB 9.5-1, ``Guidelines for Fire
Protection for Nuclear Power Plants Docketed Prior to July 1, 1976,''
February 24, 1977. Most licensees complied with most of the
implementing guidance. To resolve the contested issues, the NRC
published the final fire protection rule (10 CFR 50.48) and Appendix R
to 10 CFR Part 50 on November 10, 1980 (45 FR 76602). It is important
to note that Appendix R is not a set of generically applicable fire
protection requirements and applies only to plants that were operating
before January 1, 1979.
The record for Appendix R does not disclose the technical basis for
including the noncombustibility criterion in Appendix R. The
noncombustibility criterion is not included in BTP APCSB 9.5-1,
Appendix A to BTP APCSB 9.5-1, or in the industry fire endurance test
standards. Section 50.48 does not address the use of combustible
materials. Although GDC 3 states that noncombustible and heat-resistant
materials must be used wherever practical, GDC 3 does not preclude the
use of combustible materials. In general, when these materials are
incorporated as integral components of the plant fire protection
program, including the fire hazard analysis, they are acceptable.
Fire barrier penetration seals are one element of the defense-in-
depth concept at nuclear power plants. The objectives of the defense-
in-depth concept as applied to fire protection are to:
(1) Prevent fires from starting;
(2) Promptly detect, control, and extinguish those fires that do
occur; and
c. Protect structures, systems, and components important to safety
so that a fire that is not extinguished promptly will not prevent the
safe shutdown of the plant.
To achieve defense in depth, each operating reactor maintains an
NRC-approved fire protection program. Nuclear power plants are divided
into separate areas by structural fire barriers, such as walls and
floor-ceiling assemblies whose fire-resistance rating, typically 1, 2,
or 3 hours, is determined by testing. The function of these structural
barriers is to prevent a fire that starts in one area from spreading to
another area. Penetration seals are used to close openings through the
structural fire barriers. The intended design function of the
penetration seal is to confine a fire to the area in which it started
and to protect important equipment within an area from a fire outside
the area. As for other fire barriers, the fire-resistance rating of the
penetration seals is determined by testing.
The ability of a particular penetration seal to achieve its
intended design function (i.e., to contain a fire), as determined by a
fire endurance test conducted in accordance with an industry standard,
is the foremost design consideration. In NUREG-1552 and NUREG-1552,
Supplement 1, the NRC concluded:
(1) There are no reports of fires where fire-rated penetration
seals failed to confine a fire at a nuclear power plant;
(2) A large body of fire endurance tests has confirmed the fire-
resistive capabilities of the penetration seal materials, designs, and
configurations installed in nuclear power plants; and
(3) If penetration seals are properly designed, tested, installed,
inspected, and maintained, there is reasonable assurance that they will
provide the fire resistance of the tested design, maintain the fire-
resistive integrity of the fire barriers in which they are installed,
and confine a fire to its area of origin.
The NRC evaluated silicone-based penetration seal materials that
are combustible and are the most widely used materials for penetration
seals throughout the commercial nuclear power industry. In presenting
the results of its evaluation in NUREG-1552 and in NUREG-1552,
Supplement 1, the NRC concluded:
(1) Properly designed, tested, installed, and maintained silicone-
based penetration seals are not credible fire hazards;
(2) Despite the fact that a silicone-based penetration seal could
contribute some fuel to a fire, its relative contribution to overall
fire severity would be negligible;
(3) Qualified silicone-based fire barrier penetration seals can
accomplish their intended design function; and
(4) The benefits of combustible or limited combustible penetration
seal materials outweigh any potential concerns regarding material
combustibility. For example, the penetration seal material must be
compatible with the penetrating item material. In the case of
electrical cables, the 3M intumescent material or the Dow Corning
Silicone will not damage the cable jacket and flows between the
individual cables during installation. Likewise, the flexible
combustible seal materials allow for normal pipe movement due to
heating and cooling of the pipe. The combustible seal materials are
economical to install and remove/replace during plant modifications. In
short, silicone foam and silicone elastomer can fill complex irregular
openings and adhere to the penetration and the penetrants; cure
rapidly; have high-temperature stability; are flexible; and resist the
effects of radiation exposure and aging.
2. In Sec. 50.48, footnotes 3 and 4 are removed.
Footnote 3 to Sec. 50.48(a) stated that basic fire protection
guidance for nuclear power plants is contained in two NRC documents:
Branch Technical Position (BTP) Auxiliary Power Conversion System
Branch (APCSB) 9.5-1, ``Guidelines for Fire Protection for Nuclear
Power Plants'' (for new plants docketed after July 1, 1976), dated May
1976, and Appendix A to BTP APCSB 9,5-1, ``Guidelines for Fire
Protection for Nuclear Power Plants Docketed Prior to July 1, 1976''
(for plants that were operating or in various stages of design or
construction before July 1, 1976), dated August 23, 1976. Footnote 3
also referred to footnote 4 to Sec. 50.48(b), that lists four
additional documents related to permissible alternatives to satisfy
Appendix A to BTP APCSB 9.5-1. The documents listed in footnote 4 were:
``Supplementary Guidance on Information Needed for Fire Protection
Evaluation,'' dated October 21, 1976;
[[Page 38187]]
``Sample Technical Specification,'' dated May 12, 1977; ``Nuclear Plant
Fire Protection Functional Responsibilities, Administrative Control and
Quality Assurance,'' dated June 14, 1997; and ``Manpower Requirements
for Operating Reactors,'' dated May 11, 1978. The six documents that
were referred to in footnotes 3 and 4 no longer reflect accurately the
current NRC guidance.
Footnotes 3 and 4 were not intended to be rulemaking requirements
but rather statements of fact. The footnotes reflected the Commission's
approval of the NRC staff's practice, as reflected in Branch Technical
Position (BTP) APCSB 9.5-1 and in its Appendix A, that the date of the
docketing of the construction permit would determine the NRC staff's
review criteria for verifying compliance with General Design Criterion
(GDC) 3, and that compliance with the guidance of BTP APCSB 9.5-1 or
its Appendix A and the other listed guidance documents would establish
compliance with GDC 3. The NRC has completed its review of the fire
protection programs at all operating reactors and has issued license
conditions that establish the licensing bases for each reactor. The
licensing bases may include the documents listed in footnotes 3 and 4,
but typically include a number of other guidance documents that the NRC
issued after it promulgated Sec. 50.48. In addition, the licensees
included the fire protection licensing basis for each reactor in the
Updated Final Safety Analysis Report for the facility. Footnotes 3 and
4 have served their purpose and are not needed by the NRC or the
licensees to maintain the fire protection licensing bases for the
reactors.
The change does not affect or change the licensing basis for any
plant. However, it makes 10 CFR 50.48 consistent with other reactor
regulations that do not identify guidance documents. It also eliminates
the need to update the footnotes to include the large number of
guidance documents that the NRC has issued since it promulgated
Sec. 50.48 and to conduct future rulemakings to add new guidance
documents as they are issued. The change also resolves an inconsistency
between the information in footnote 3 to Sec. 50.48 and the regulatory
requirements of Sec. 50.34(g)(1)(ii). Specifically Sec. 50.34(g)(1)(ii)
states, in part, that ``Applications for light water cooled nuclear
power plant construction permits, manufacturing licenses, and
preliminary or final design approvals for standard plants docketed
after May 17, 1982, shall include an evaluation of the facility against
the SRP * * *,'' whereas, footnote 3 indicated that the fire protection
portions of these applications would be reviewed against BTP APCSB 9.5-
1.
3. In Section I of Appendix R, footnote 1 is removed.
Footnote 1 to Section I in Appendix R is identical to footnote 4 to
Sec. 50.48(b). The reasons given above for the removal of footnote 4 to
Sec. 50.48(b) also apply to footnote 1 to Section I in Appendix R.
4. In Sec. 50.48, paragraphs (c), (d), and (e) are removed.
Paragraphs (c) and (d) of Sec. 50.48 contained schedule
requirements that were added to the Code of Federal Regulations when
Appendix R became effective on February 17, 1981. These requirements
applied to nuclear power plants licensed before January 1, 1979, and
involved fire protection installation modifications, revisions of
administrative controls, manpower changes, and training. These
requirements were to be completed on a schedule determined by the
provisions specified in Sec. 50.48 (c) and (d). All scheduler
requirements of Sec. 50.48 (c) and (d) have been implemented and need
not be retained.\1\
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\1\ The removed paragraphs read as follows:
(c) All fire protection modifications required to satisfy the
provisions of appendix R to this part or directly affected by such
requirements shall be completed on the following schedule:
(1) Those fire protection features that involve revisions of
administrative controls, manpower changes, and training, shall be
implemented within 30 days after the effective date of this section
and appendix R to this part.
(2) Those fire protection features that involve installation of
modifications that do not require prior NRC approval or plant
shutdown shall be implemented within 9 months after the effective
date of this section and appendix R to this part.
(3) Those fire protection features, except for those requiring
prior NRC approval by paragraph (c)(5) of this section, that involve
installation of modifications that do require plant shutdown, the
need for which is justified in the plans and schedules required by
the provisions of paragraph (c)(5) of this section, shall be
implemented before startup after the earliest of the following
events commencing 180 days or more after the effective date of this
section and appendix R to this part:
(i) The first refueling outage;
(ii) Another planned outage that lasts for at least 60 days; or
(iii) An unplanned outage that lasts for at least 120 days.
(4) Those fire protection features that require prior NRC
approval by paragraph (c)(5) of this section, shall be implemented
within the following schedule: Dedicated shutdown systems -- 30
months after NRC approval; modifications requiring plant shutdown--
before startup after the earliest of the events given in paragraph
(c)(3) commencing 180 days after NRC approval; modifications not
requiring plant shutdown--6 months after NRC approval.
(5) Licensees shall make any modifications necessary to comply
with these requirements in accordance with the above schedule
without prior review and approval by NRC except for modifications
required by section III.G.3 of appendix R to this part. Licensees
shall submit plans and schedules for meeting the provisions of
paragraphs (c)(2), (c)(3), and (c)(4) within 30 days after the
effective date of this section and appendix R to this part.
Licensees shall submit design descriptions of modifications needed
to satisfy section III.G.3 of appendix R to this part within 30 days
after the effective date of this section and appendix R to this
part.
(6) In the event that a request for exemption from a requirement
to comply with one or more of the provisions of Appendix R filed
within 30 days of the effective date of this rule is based on an
assertion by the licensee that such required modifications would not
enhance fire protection safety in the facility or that such
modifications may be detrimental to overall facility safety, the
schedule requirements of paragraph (c) shall be tolled until final
Commission action on the exemption request upon a determination by
the Director of Nuclear Reactor Regulation that the licensee has
provided a sound technical basis for such assertion that warrants
further staff review of the request.
(d) Fire protection features accepted by the NRC staff in Fire
Protection Safety Evaluation Reports referred to in paragraph (b) of
this section and supplements to such reports, other than features
covered by paragraph (c), shall be completed as soon as practicable
but no later than the completion date currently specified in license
conditions or technical specifications for such facility, or the
date determined by paragraphs (d)(1) through (d)(4) of this section,
whichever is sooner, unless the Director of Nuclear Reactor
Regulation determines, upon a showing by the licensee, that there is
good cause for extending such date and that the public health and
safety is not adversely affected by such extension. Extensions of
such date shall not exceed the dates determined by paragraphs (c)(1)
through (c)(4) of this section.
(1) Those fire protection features that involve revisions of
administrative controls, manpower changes, and training shall be
implemented within 4 months after the date of the NRC staff Fire
Protection Evaluation Report accepting or requiring such features.
(2) Those fire protection features involving installation of
modifications not requiring prior approval or plant shutdown shall
be implemented within 12 months after the date of the NRC staff Fire
Protection Safety Evaluation Report accepting or requiring such
features.
(3) Those fire protection features, including alternative
shutdown capability, involving installation of modifications
requiring plant shutdown shall be implemented before the startup
after the earliest of the following events commencing 9 months or
more after the date of the NRC staff Fire Protection Safety
Evaluation Report accepting or requiring such features:
(i) The first refueling outage;
(ii) Another planned outage that lasts for at least 60 days; or
(iii) An unplanned outage that lasts for at least 120 days.
(4) Those fire protection features involving dedicated shutdown
capability requiring new buildings and systems shall be implemented
within 30 months of NRC approval. Other modifications requiring NRC
approval prior to installation shall be implemented within 6 months
after NRC approval.
(e) Nuclear power plants licensed to operate after January 17,
1979, shall complete all fire protection modifications needed to
satisfy Criterion 3 of appendix A to this part in accordance with
the provisions of their licensees.
---------------------------------------------------------------------------
Paragraph (e) of Sec. 50.48 specified that nuclear power plants
licensed after January 1, 1979, were to complete all fire protection
modifications needed to satisfy GDC 3 of Appendix A to 10 CFR Part 50
in accordance with the provisions of their licenses. License
[[Page 38188]]
conditions pertaining to fire protection have been implemented at all
plants. Therefore, Sec. 50.48(e) has been implemented and need not be
retained.
5. In Section III.G.3 of Appendix R, a grammatical error is
corrected.
Footnote 2 to Section III.G.3 of Appendix R read, ``Alternative
shutdown capability is provided by rerouting, relocating, or
modificating of existing systems; dedicated shutdown capability is
provided by installing new structures and systems for the function of
post-fire shutdown.'' This final rule replaces the words ``modificating
of'' with ``modifying.''
IV. Plain Language
The Presidential memorandum dated June 1, 1998, entitled, ``Plain
Language in Government Writing,'' directed that the Federal
Government's writing be in plain language (63 FR 31883, June 10, 1998).
In compliance with this directive, editorial changes have been made in
these amendments to improve the readability of the existing language of
the provisions being revised. These types of changes are not discussed
further in this document.
V. Compatibility of Agreement State Regulations
Under the ``Policy Statement on Adequacy and Compatibility of
Agreement State Programs'' approved by the Commission on June 30, 1997,
and published in the Federal Register September 3, 1997 (62 FR 46517),
Part 50 is classified as compatibility Category ``NRC.'' The NRC
program elements in this category are those that relate directly to
areas of regulation reserved to the NRC by the AEA or provisions of
Title 10 of the Code of Federal Regulations.
VI. Voluntary Consensus Standards
The National Technology Transfer Act of 1995, Public Law 104-113,
requires that Federal agencies use technical standards that are
developed or adopted by voluntary consensus standards that are
developed or adopted by voluntary consensus standards bodies unless the
use of such a standard is inconsistent with applicable law or otherwise
impractical. The NRC is deleting the Government-unique standard in 10
CFR Part 50, Appendix R, Section III.M, which requires that fire
barrier penetration seals utilize only noncombustible materials. The
NRC is not aware that deletion of this requirement is inconsistent with
any voluntary consensus standard.
VII. Finding of No Significant Environmental Impact
Environmental Assessment
The NRC has determined, in accordance with the National
Environmental Policy Act of 1969, as amended, and the Commission's
regulations in Subpart A of 10 CFR Part 51, that the amendments are not
a major Federal action significantly affecting the quality of the human
environment; therefore, an environmental impact statement is not
required.
1. The Action
The NRC is amending its regulations that require fire barrier
penetration seal materials to be noncombustible and making minor
changes to Sec. 50.48 and to Appendix R to Part 50.
These minor changes are to remove footnote 3 from Sec. 50.48(a),
footnote 4 from Sec. 50.48(b), and footnote 1 from Section I in
Appendix R; remove paragraphs (c), (d), and (e) from Sec. 50.48;
correct a grammatical error in footnote 2 to Section III.G.3 of
Appendix R; and make editorial changes.
2. Need for the Rulemaking Action
The technical basis for removing the noncombustibility requirement
for fire barrier penetration seal materials is documented in NUREG-
1552, ``Fire Barrier Penetration Seals in Nuclear Power Plants,'' July
1996; and in NUREG-1552, Supplement 1, January 1999. In these reports,
the NRC staff documented the results of a technical assessment of fire
barrier penetration seals. On the basis of its findings, the NRC
concluded that the noncombustibility criterion for penetration seal
materials specified in the NRC fire protection regulations and review
guidance has a negligible contribution to safety and recommended that
this noncombustibility criterion be deleted. In a staff requirements
memorandum dated June 30, 1998, the Commission directed the NRC staff
to amend Section III.M of Appendix R to 10 CFR Part 50 (Appendix R) to
eliminate the noncombustibility requirement for penetration seal
material and to make other minor changes to the fire protection
regulations. These minor changes include the deletion of references
that no longer reflect accurately the guidance documents published by
the NRC in footnotes 3 and 4 of Sec. 50.48 and in footnote 1 to Section
I of Appendix R, the deletion of schedular requirements that have been
implemented in Sec. 50.48(c) and (d), and a grammatical correction in
footnote 2 to Section III.G.3 of Appendix R. The NRC also took
advantage of this rulemaking to make editorial changes to comply with
the Presidential memorandum dated June 1, 1998, entitled, ``Plain
Language in Government Writing.'' The deletion of the noncombustibility
criterion removes a requirement that has a negligible contribution to
safety. It constitutes a burden reduction for the NRC and for the
licensees.
3. ``No Regulatory Action'' Alternative
No regulatory action would have continued the regulatory burden on
licensees and on the NRC. Silicone-based material is currently the
material of choice for fire barrier penetration seals and is
combustible. The NRC has performed an assessment of silicone-based
penetration seal materials and concluded that the benefits of the
silicone-based materials in penetration seals, such as high-temperature
stability, flexibility, and resistance to the effects of radiation
exposure and aging, outweigh any potential concerns regarding material
combustibility. In the past, licensees using silicone-based penetration
seal materials have requested and been granted exemptions from the
requirement of Section III.M of Appendix R to Part 50, regarding the
use of noncombustible materials, provided the seals are qualified by
fire endurance tests conducted in accordance with an industry standard.
Under the previous rule, a licensee that chose penetration seals made
of silicone-based materials to replace existing seals or to install new
seals would have had to request an exemption from the requirement of
Section III.M of Appendix R to the extent that the silicone-based
material is combustible. This request for an exemption would have
increased the regulatory burden on both the NRC and the licensees, and
would have presented no safety benefit. No regulatory action regarding
the removal of footnote 3 to Sec. 50.48(a), footnote 4 to Sec. 50.48
(b), footnote 1 to Section I of Appendix R, and Sec. 50.48 (c), (d),
and (e) would have had a negative regulatory impact for the following
reasons. Footnotes 3 and 4 in Sec. 50.48 and footnote 1 to Section I of
Appendix R were inaccurate and incomplete. In addition, the information
in footnote 3 was inconsistent with the regulatory requirements
contained in Sec. 50.34(g)(1)(ii). The requirements in Sec. 50.48 (c),
(d), and (e) had been implemented and need not be retained. No
regulatory action regarding the correction of a grammatical error in
footnote 2 to Section III.G.3 of Appendix R to Part 50, which was
administrative in nature, would not have had any regulatory impact.
[[Page 38189]]
4. Environmental Impacts of the Proposed Amendment and the Alternative
The environmental impacts of this amendment, as well as the
alternative, are considered negligible by the NRC. The NRC has
determined that the ability of a particular penetration seal to achieve
its intended design function (i.e., to contain a fire), as determined
by a fire endurance test conducted in accordance with an industry
standard, is the foremost design consideration. The amendment will not
impact the ability to shut down the plant safely in the event of a fire
and will provide a level of safety equivalent to that attained by
compliance with Section III.M of Appendix R to 10 CFR Part 50. There is
no environmental impact associated with the other changes which are
administrative in nature. On this basis, the NRC concludes that there
are no radiological environmental impacts associated with this
amendment. If no regulatory action had been taken in regard to the
noncombustibility requirement of Section III.M of Appendix R there
would have been no radiological environmental impact, the same as the
action. No regulatory action regarding the changes in Sec. 50.48 and in
Appendix R (and the correction of an error in footnote 2 to Section
III.G.3 of Appendix R, which is administrative in nature) would have
had no radiological impact on the environment.
With regard to potential nonradiological impacts, the amendment
does not affect nonradiological plant effluents and has no other
environmental impact. Therefore, the NRC concludes that there are no
significant nonradiological environmental impacts associated with the
amendment.
5. List of Agencies and Persons Consulted
Much of the technical information required for this rulemaking was
obtained directly from technical experts within the NRC. No other
agencies were consulted in preparing this environmental assessment.
VIII. Paperwork Reduction Act Statement
This final rule does not contain a new or amended information
collection requirement subject to the Paperwork Reduction Act of 1995
(44 U.S.C. 3501 et seq.). Existing requirements were approved by the
Office of Management and Budget, approval number 3150-0011.
Public Protection Notification
If a means used to impose an information collection does not
display a currently valid OMB control number, the NRC may not conduct
or sponsor, and a person is not required to respond to, the information
collection.
IX. Regulatory Analysis
The NRC has prepared the following regulatory analysis for the
rule.
1. Statement of the Problem
The NRC is amending its regulations regarding the requirement for
fire barrier penetration seal materials to be noncombustible and is
also making minor changes to Sec. 50.48 and to Appendix R to 10 CFR
Part 50. The changes remove footnote 3 from Sec. 50.48(a), footnote 4
from Sec. 50.48(b), and footnote 1 from Sect. I. of Appendix R; remove
paragraphs (c), (d), and (e) from Sec. 50.48; correct a grammatical
error in footnote 2 to Section III.G.3 of Appendix R; and make
editorial changes to comply with the Presidential memorandum dated June
1, 1998, entitled, ``Plain Language in Government Writing.''
2. Objectives of the Rulemaking
The main objective of the rule is to remove the requirement of
Section III.M of Appendix R to 10 CFR Part 50 that fire barrier
penetration seal materials be noncombustible. In addition, this rule
removes certain parts of Sec. 50.48 and of Appendix R, corrects a
grammatical error in Appendix R, and makes editorial changes.
3. Alternative
The alternative of no regulatory action would have continued the
unnecessary regulatory burden on licensees and on the NRC.
4. Consequences
Removing the requirement that fire barrier penetration seal
materials be noncombustible from Section III.M of Appendix R to Part 50
lessens the unnecessary regulatory burden on licensees and on the NRC
staff. It allows licensees to use combustible materials in penetration
seals without requesting an exemption from the requirement in Section
III.M of Appendix R regarding the noncombustibility of penetration seal
materials, provided the seals are qualified by fire endurance tests
comparable to those used to rate fire barriers and conducted in
accordance with an industry standard. The other minor changes are
administrative and do not affect the regulatory burden on licensees.
5. Value Impact Analysis.
The value (benefit) and impact (cost) of the changes are estimated
below. Section III.M of Appendix R to 10 CFR Part 50 applies to the
plants that were operating before January 1, 1979, and had open items
when Appendix R was published. As detailed in NUREG-1552, Supplement 1,
Section III.M of Appendix R applies to 5 operating reactors. In order
to estimate the benefit of the change, the NRC assumes that the
licensees for these plants may want to replace some of their
penetration seals with penetration seals made of silicone-based
combustible material and that these licensees would request an
exemption from the technical requirements of Section III.M of Appendix
R. Labor cost is $145/hr for a power reactor licensee and $75/hr for
NRC. The change to Section III.M of Appendix R would save licensees the
cost of preparing an exemption request and would save the NRC the cost
of preparing a safety evaluation and processing the request. Assuming a
cost saving of approximately $7500 for licensees and approximately
$2500 for NRC for each exemption request, the total cost saving from
the change to Section III.M would be approximately $50,000. There would
be no benefit or cost associated with the other proposed changes.
6. Decision Rationale
The NRC reviewed the requirement of Section III.M of Appendix R
during its reassessment of fire barrier penetration seals and
determined that this requirement has a negligible contribution to
safety. The removal of the requirement of Section III.M reduces the
regulatory burden on the licensee without reducing safety. In addition,
the rule makes the following minor changes: removes footnote 3 from
Sec. 50.48(a), footnote 4 from Sec. 50.48(b), and footnote 1 from
Section I of Appendix R; removes paragraphs (c), (d), and (e) from
Sec. 50.48; corrects an error in footnote 2 to Section III.G.3 of
Appendix R; and makes editorial changes to comply with the Presidential
memorandum dated June 1, 1998, entitled, ``Plain Language in Government
Writing.'' The other changes as discussed above do not change the
regulatory burden on the licensees and do not affect safety.
X. Regulatory Flexibility Act Certification
As required by the Regulatory Flexibility Act of 1980 (5 U.S.C.
605(b)), the Commission certifies that this rule does not have a
significant impact on a substantial number of small entities.