ML111530446
| ML111530446 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 06/01/2011 |
| From: | Pilgrim Watch |
| To: | Atomic Safety and Licensing Board Panel |
| SECY RAS | |
| Shared Package | |
| ML111530440 | List: |
| References | |
| RAS 20407, 50-293-LR, ASLBP 06-848-02-LR | |
| Download: ML111530446 (7) | |
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Ple2sc lc't Li2 h\\Ci~" if yo," concur; if l:ot, \\-l,~ 'dill hc!ve to di.scuss it fur::.hc.r and reoch a decision',
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- 1.
Def:initic~l:
Bypass m~~ns n rath without passinG th::ough the,:2ter of the suppression pool and therefore without condensing th~
- 2.
Consen\\lC'nces a)
L~rge LOCh -
no problem.
b)
Small LOCA -
slow pressure buildup in dryoell, bypass lets wetwcll pressure follow without cond~nsing steam.
This trouble cases on slowly, but if the prim3ry leak widens and the LOCA severity in-creases (the advertised course of cvc~ts for a big leak starts 5m311) then the bi~
.. /. -
b10,:doh'n p,-essure vill build on the c.:":istin~; pressure built up sJ.O'.;l::.') and the con-taiument would overpr~ssurize.
That could l03~ the torus
~
water source, hence ECeS, as well as leak out fission products.
- 3.
Prob2bility a)
Small pri~3ry lLak rather probable -
alreauy hnd one S10'.7 blowdown (Dresden 2).
Another (Honticello) b1m'ldmm occurred through the byp:,ss valve, then through a safety valve.
A large leak i~ improbable, but is supposed to be a small one first.
b)
GE claim~ two passive failures b)
The GE position that this are required for trouble, but is too improbable to any malfunction of 12 vacuum worry about is rejected.
sp~cted in the locus, over ~O y~3rs will set up half th8 accident, rc~dy {or tr6~blc if
- a. s tC0.:~ leak occurs.
c) 0;11)" a limited L',r~f:~ of lc:,-~~
c)
Further study is required sizes gets into trouble.
for this and other configura-Large L!aks clc;lr the VC.l1ts tions, including sensitivity and assumption va~iations.
postulated bypass.
Very snaIl leaks are condensed on the dry>*,cll,,70.11.
Thc "t~:2ched GE cu;::ve subrailted foc E",:~,:h ?
has not been revicw~d very much by REG) shQ";.Js SOt:le troub]-,~
0.05 - 0.5 ft. 2 Other GS containments (s~311er 0= over/
under with ~eepcr vents, or other parameters dif[cre~t).
have problems not yet calcu-latc~ and, in some cases, worse than Ho.tch.
'V "eli ~. - ()~l
.DECFIO::S
'r--
~------------- --
/
a)
Containment spray (particularly torus air s pac e spr<lY)
\\7C'~i lcl We cnnnot expect an operator 0 condense t 1t c. s t CeliU and L! e ~ -;,:c G.S C.
the r,ravcyarc! shift to sort ou the pressure, but at enormous the pros and con~ of turning cost (ruin equipment in dry-oti the containree~t sprny, w~ll, maybe hnve to retire thus ruining his reactor) to reactor).
In present designs, cope \\*11 lh a trarsicnt he -only contain~cnt spray water is dimly undcrstan2s.
diverted fro:;\\ the LPCIS, thus from Eces.
b)
Inservice inspection of poten-b)
Check the! valve ~.lu [f c~re-tial bypass leakage:
corrosion, fully to make sure it cracks in vent pipes, nalfunc-doesn't increas~ (too ~u~~)
tioning valves.
The Ha:ch the probability of f<1i1u:::e..
applicant offcrs an elaborate Push for adequate inspection I
scheme to inc~ica::e the' positions of valves and pipes.
of the: valves using rec1u:1cL:mt devices) and to allo~l rC;010te testing of the valves, but nothing in the H.JY of inspection.
DEcr STO:~S ication
--<..A.-______._
\\
past and prcse~t CE prcss~re-co~~it~cnt to stu2y 2~d fix the problc~ in whatever 40 such ar~ already app~u~2d.
way is fou~~. F6r back-Hatch-2 C? is th~ next ACRS fitting. wait until fixQ5 revie\\.].
are studied and problem is scope:d.
b)
CE wants us and ACRS not to mention the ~roblen publicI;.
from nml on for plants They are afraid of delaying affected will have to 'fcss up.
Hearings for CP s~0ul~
be satisfied,;Hh a s<.:itab 1 commitment; if they're not.
maybe that's a suitable spu-::- to CE-to resolve the problel:l.
In any event-, th is probably trouble for Vermont Yankee and Pilcri~
hearings; it will have to
)
DECISTO::S faced ~nd a real solutio~
found.
All GE prc3sure stippression cases in hearinG
,*lill soon have to Get letters fio~ REG aboutth~ problen; better that they hear from us than from 2~ ACRS letter on. another caSe.
2 CP ACRS letter docs nat mention the problem, thus giving us a li:t c more time.
The subject is dis-cussc~ in the ?ublicly aV0.ilaolc Hatch-2 docket as an ::mSiJer to a DRL question.