Disposal of Gaseous Nuclear Waste

[Mark Robert Thorson]

I've heard that radioactive krypton and xenon gas are normally
released to the atmosphere during nuclear power plant operations.
These are fission products which happen to be gases. I'd like
to know if there are any recovery systems for these gases, or
is the whole amount generated by fission released? And, how
much gas are we talking about, say, relative to the amount of
cesium and strontium being generated? Are we talking about
milliliters, liters, or kiloliters?

[George T Strickland]

If you are in reference to the Krypton and Xenon relased in the fuel
as fission products, they are retained in the fuel. A small amount may
leach through the cladding but it would be a SMALL amount. I know of
no operating plant that releases any Krypton or Xenon. The fission
yield of Kr is about 1.3% from 3% enriched U-235. I don't have the
numbers on Xe with me right now but if there is interest I'll post
them.

George

--
|
George Strickland | "You measure time with a clock and
stri...@gn.ecn.purdue.edu | space with a ruler"
Purdue University | -A. Einstein

[John De Armond]

stri...@gn.ecn.purdue.edu (George T Strickland) writes:

>In article <53...@cup.portal.com> m...@cup.portal.com (Mark Robert Thorson) writes:
>>I've heard that radioactive krypton and xenon gas are normally
>>released to the atmosphere during nuclear power plant operations.
>>These are fission products which happen to be gases. I'd like
>>to know if there are any recovery systems for these gases, or
>>is the whole amount generated by fission released?

>If you are in reference to the Krypton and Xenon relased in the fuel

>as fission products, they are retained in the fuel. A small amount may
>leach through the cladding but it would be a SMALL amount. I know of
>no operating plant that releases any Krypton or Xenon. The fission
>yield of Kr is about 1.3% from 3% enriched U-235. I don't have the
>numbers on Xe with me right now but if there is interest I'll post
>them.

Not quite true. There are always failed fuel pins in any operating
core. Tech specs place limits on the percentage. As a practical result,
there is always some noble gas released from the core. As a result,
all plants are equipped with what is called the off-gas processing system.

The two isotopes of concern are Xe-133 and Kr-85 with half-lives of
5.25 days and 10.6 years respectivly. The OGPS simply concentrates the
off-gas and holds it in tanks until the Xe-133 decays. Then the remaining
Kr-85 is slowly purged to atmosphere at a rate in keeping with the
plant's tech spec limit on emissions.

The total annual quanitity released for a 1000 MWE plant is in the few
tens of curies, physically a few grams.

John

--
John De Armond, WD4OQC | If Congress ever does something purely
Rapid Deployment System, Inc. | in the interest of the nation, Lincoln
Marietta, Ga | will get up, stroll over to congratulate
j...@dixie.com | them.