ML19347E519
| ML19347E519 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 05/06/1981 |
| From: | Hovey G METROPOLITAN EDISON CO. |
| To: | Barrett L Office of Nuclear Reactor Regulation |
| References | |
| LL2-81-0123, LL2-81-123, NUDOCS 8105120325 | |
| Download: ML19347E519 (2) | |
Text
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g Metropolitan Edison Company Post Office Box 480 f' {-
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Middletown, Pennnivania 17057 j
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May 6, 1981
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$@o TMI Program Office y
Attn:
Mr. Lake Barrett, Deputy Director Is U. S. Nuclear Regulatory Commission 3
g c/o Three Mile Island Nuclear Station g
3 Middletown, Pennsylvania 17057 e
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Dear Sir:
Three Mile Island Nuclear Station, Unit 2 (TMI-2)
Operating License No. DPR-73 Docket No. 50-320 Submerged Demineralizer System In our April 24, 1981 submittal (LL2-81-0111) we stated:
"Available water radiolysis data for irradiated zeolite systems indicate that recombination will occur (under scmm: flux field) and subsequent hydrogen / oxygen concentrations would be non-explosive."
This letter further elaborates on the above statement and provides a basis for it.
Experiments by K. K. S. Pillay (NE/RWM-80-3, " Radiation Effects on Ion Exchangers Used in Radioactive Waste Management," Department of Nuclear Engineering, Pennsylvania State University, University Park, PA 16802) and analysis using the computer program MAKSLMA CHEMIST (M. B. Cower, D. V. Hanely, and N. R. Chaplin, Atomic Energy of Canada, LTD. Report AECL-6413,1979) indicate thac recombination occurs and equilibritrn pressure is low.
Pillay irradiated eight capsules containing wet zeolite.
Six capsules yielded hydrogen gas concentrations in the range 0.6 vo1% to 1.3 vol%
with oxygen present at 24.1 vol% to 36.9 vo1% at total gas pressures of 11.6 psi to 20.3 psi.
The other two capsules yielded hydrogen concentrations of 3.1 vol% and 4.5 vo1%; however, in these capsules the oxygen was depleted (0.5 vol% to 1.3 vol%).
Scaling Pillay's exposure rate to the dose rate corresponding to 60,000 Ci/ vessel yields hydrogen concentrations of.74 vol% to 1.6 vol% (6 samples) and 4.5 vol% to 5.6 vol% (2 samples).
Such gas mixtures (with the arrespond-ing scaled oxygen concentrations) are non-explosive. Pillay's data also suggests the presence of absorbed nitrogen which was relea<ed after the capsules were sealed. Absorbed gas in the SDS vessels would be unlikely.
In absence of such gas, Pillay's experimental data still predicts a non-explosive mixture.
$$f Metrocontan Ed: son Company is a r/emcer of the General Dut:lic Utat:es System
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ifr. Lake Barrett LL2-81-0123 The MAKSIMA CHEMIST computer code computed equilibrium hydrogen concencrations in the range 5 vul% to 14 vol% and oxygen concen-trations in the range 18 vol% to 20 vol% with equilibrium gas pressures less than 1.18 atm.
Hydrogen is flamable in the range 4 vol% to 72.2 vol% and generally explosive in the range 14 vol%
to 68 vol%. Explosion of the 14 vol% gas mixture would result in an over pressure of 5.15 atm, which would be safely contained.
Furthermore, this explosion will not occur; no credible ignition source exists (the vessels ars under water) and the zeolite will be continuously cooled by vapor recondensation.
Should you wish to discuss this matter further, please contact Mr. L. J. Lehman,.i. of my staff.
t Sincerely,
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. K. Hovey Vice-President and Director, TMI-2 GKH:LJL:vj f cc:
Dr. B. J. Snyder, Program Director - TMI Office m
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