ML19210C617
| ML19210C617 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 05/19/1979 |
| From: | Boss D Office of Nuclear Reactor Regulation |
| To: | Vassallo D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19210C589 | List: |
| References | |
| NUDOCS 7911190178 | |
| Download: ML19210C617 (3) | |
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MAY l 9 B78 ME".0EANDUM FOR: D.E _Vassallo, Assistant Director for UG.'s, DPH [h6 G
FROM:
D.F. Ross, Jr.., Assistant Director for Reactor Safety, DSS
SUBJECT:
B0'RD NOTIFICATION - WESTINGHOUSE ECCS E'lALUATION H0 DEL ERROR (BN-118)
P.eference:
D.3. Vassallo letter to R.d. Mattson dated 1pril 20,1978 -
Same subject.
We believe that appropriate hearing boards should be no-ified of the subject error on plants not yet granted an operating li:ense or a construction permit.
- n acccrdance with our evolving guidelines, boards shou.d be informed cnly ir. those cases where the SER supplement has been issued.
Other cases snould address the issue in SER's or SER suppleme-ts.
As ncted in the enclosure to the referenced letter, Wes:irghouse has ciscussed the error with us.
Westinghouse performed ca'culations with tne error corrected which showed that some plants would not meet the 22CO'F limit of 10 CFR 50.46.
Correction of the error always results in'an increase,in peak cladding temperature (PCT).
The amount can be sensitive to cladding rupture dynamics.
Generally the increase is in the rar.ge of 75'F to 200*F.
In order to avoid reductions in overall peaking factor lF ), Westinghouse e
recor:nended otner compensatory changes in their evaluatio." model.
We
-t are reviewing these changes and others (including accu =1ator delivery) and expect resolution by July 1.
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Tne ap:r:: Hate heards snould be informed that our review will be
.c:=siete.:y July b 1975, and that ECCS analyses in conformance wita 10 2R 53.45 and Appendix X will be available soon after that time.
If a liter. sing action is required on a particular case, the aoplican snould s:.:b:it analyses with only the error fixed.
If this is d:ne witneut cor. sideration of compensating changes, we believe tne analyses would be in conformance with Appendix K.
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D.F: Ross, Jr., Assistant Director for P.eactor Sa fety Division of Systems Safety c::
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ENC' 01URE 2 DRAFT PRO?05E2 BOARD LETTER
^- !! arch 23,1978, Westinghouse informed the staff that they.had, discovered an, error in the LOCTA program used to calculate peak c' adding temperatures (FCT) in their ECCS evaluation model.
On 14 arch 29, they made a detailed presentation on the subject to !!RC in Bethesda.
The error, which also existed in SATAN, had the effect of catsing the metal-water reaction heat release to be one-nalf af whr, it should be. The error and its confirmation were explained Westinghouse perforced calculations with the error correctec, which showed that ser.e plants would not meet the 2200 F limit M 10 CFR 50.46.
Correction of-the error always results in an ircrease in PCT.
The amount can be sensitive to cladding ruoture dynamics.
Generally the increase is in the range of 750F to 2000F.
In order to avoid reductions in overall peaking factor (F ),
q Westinghouse recc=nended other compensatory changes in their evalua-tion model.
We are reviewing these changes and others (including accumulator delivery) and er.pecc our evaluation to be complete about July 1, 1978.
It is noted that this concern is most applicable to plants ready to be licensed for operation.
Even if the evaluation is not com-pleted or if the ccepensatory changes are not approved, the applicant will be able to operate with a reducticn in peaking factor in order to compensate for the error.
For construction permit plants we consider the notification to be for information only.
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NORTH ANNA ENVIRONNIENTAL COALIT Charlottesville, Virginia Mailing Address:
412 hs Mrs A. Chairman Joseph P. Hendrie 2=stavil16, AlabamLa 35801 Commissioner John F. Ahearne (205) 556-0678 Commissioner Peter Bradford August 13, 1979 Commissioner Victor Gilinsky U. S. NUCLEAR REGULATORY CO)i.4ISSION Re-W ECCS Defects--
Washington, D. C.
20555 Potential Fcapture of Gentlemen:
Zireonium Cladding On April 4 and 5,1979, the North Anna Environmental Coali-tion (NAEC) requested the NRC Appeal Board and Commissioners re-spectively to remove North Anna and Surry operating licenses because of a Westinghouse (1) error in its ECCS analysis related to the po-tential rupture of zirconlus claading.
NAEC also asked the consid-eration of similar action at other E plants.
Since that time, we have had an opportunity to study the se-quence of events in the spring of 1978 after Westinghouse learned of tne ECCS error from its subsidiary in France on diarch 15, 1978.
We have prepared a chronoloey to illustrate the significant rela-tionship of those events both to the full-power licensing of North Anna on 4-1-70 and to the Three >1ile Island accident on 3-28-79.
n the briefest of chronological summaries must raise questions:
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4 h 28/29,1978.....E made presentation to NRC staff on its f,4 df N
- a' n 30, newly discovered ECCS metal water error; by I
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d 1978........vEP;o complet ed and submitt ed reanalysis of "the full effect of the metal-water reaction d
heat release," renewed and approved by two C>
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committees, with the deficiency resolved; arch 30, 1978........ye t also on A
60 VEPCO notified the Appeal Board of the de-ficiency which micht reouire reanalysis.
March 31, 1978........NRC approved VEFCO's 3-30-7d reanalysis in SER Supplement 9.
April 1, 1978.........NRC issued f ull power license for North Anna.
'4j March 28, 1979........T>!I accident involved metal-water reaction M
and damaged cladding.
March %, 1979.........NRC stali notified Boarcs re w's " metal-water Y
error" of 1978 4
May 3, 1979...........NRC to ld NAEC that although E's croblem had not L'
been solved over all, it Q solved at VEPCO.
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NAEC requests the Commission to investicate how a problem still un-
> solved by W in 1979 could have been solved so rapidly by VEPCO in 1976 d vias the quick 1976 solution a v&d_ solution?
If so, why cid VEPco no-htify the Appeal Boarc of a deficiency on the same day--March 30, 1976--
'it achieved a solution through reanalysis? Is that 1978 "sclution" crendered invalid by new cladding knowledge from tiI?
Given the known and unknown risks of zirconium cladcing, NAEC further recuests the Commissioners to review and reverse the Aueust 6 A5LB cecision to cancel tne spent fuel poo; expansion nearine rezard-ing ine InstaA11on ol nicn censity racAs a
..ortn Anna.
i.. c pressure to reluel oy y-13-iy saouto r.ot suwer; sa12ty.
I r.a n d you f or your prof essional consiceration.
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Er.c l o su re :
Chronolo gy j g j g g ne Allen.
.\\ E.C President
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