ML19269C637
| ML19269C637 | |
| Person / Time | |
|---|---|
| Site: | Atlantic Nuclear Power Plant  |
| Issue date: | 04/11/1975 |
| From: | Kouts H C NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| To: | Case E Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19261A713 | List: |
| References | |
| NUDOCS 7902070018 | |
| Download: ML19269C637 (2) | |
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?Jscu G. Case, Acting Diractor-Office of Nuclear Reactor Regulation CCRZ _EL"' CONSIDERATICNS A:O ALTIRNAT!72 PROCEDU?IS FCR PRCCESSING IHZ FLOX"IT, NUCLF.52 FG.'IR PLLNT A??LICA!!ONS In r2spense to your =a:cra:6c:s of I' arch 31, 1975, we have the following ce==ents:
1.
It is suggested that =uch of the discussion en pages 1-8, related to staff usage of probabilistic techniques and to probabilitias of core melt accidents is not useful in this document. The issue with 3.
s appears to be not as such telated to accident probabilities as it is to whether accidents in F'2's can have markedly different consequecces than land based reacters.
2.
Page 9.
It appears inappropriate to speculate that the acute consequences of a pot
core maltd:vn in an FN? veuld not differ greatly from those of a _and based plant. At=cspheric dispersion over water is quite poor and de distance thac the plu=e travels over water before contacting land =ay not cause significant dilution of the pl==e cencentration.
There are two other significant factors to consider:
a) C: the one hand, the pess3.bility of stess explosions and sea water-fuel chemical reactions when selt-through occurs =ay result is increased release of radioactivity from the fuel.
b) On the other hand, it is not apparent that the =ost likely potential contain=ent failure mode for an F'iF vill be due to over pressurization rather than =elt-through.
There are potential significant advantages in decreasine the a=ount of fission products released to the at=osphere by absorption in water by assuring that the cost likely path for contaic=ent failures venid be melt-through. In a Ekl BWR contain=ent, 7
7 P x 7 = 5 x 10 ; in an FNP it is about 4 x 10.
In a BWR F,ti, the H ing for failure by over-pressurization versus melt-through is a close race. Althcugh the PV product appears to be al=ost the sa=e for an F'2, the bottes concrete thickness is significantly less (~3' vs. -12').
S=all adjust =ents in dasign could =ake bottes =elt-through the core likely failure
- ode, if it is not so already.
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Edson O. Case UE ' 1 D 3.
C=e of the key issues for ne's is whether ths ec: sequences of p0:astial core nel:-chrough can be significan:17 differe.: in ta:=s of dispersion of co:-volatiles in the ocean.
I: vould seem that this questica could not be answered well without coeducting about a one year R&D program.
4.
One'vay to go ahead now with R2's vould be to have the first few plants surrounded by ra i=pe=eable barrier (or be placed in a sealed lag =en) that itenld obda:e the caed to consider the ocaan dispersion of radicactivity. This course vould nake enough ti=e readily availabla to permit resolution of the issues surrounding B7's constructed without such barriers.
5.
If the alternative presented in paragraph 4 above is not feasible, we vould favor your alternative 4 as the beat way to proceed.
f I
Herbert J. C. ". uts, Oiree:or 1
Office of Nuclear Regulatory 22 search O
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