ML19276F853
| ML19276F853 | |
| Person / Time | |
|---|---|
| Issue date: | 07/25/1977 |
| From: | Gossick L NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO) |
| To: | Sherwood G GENERAL ELECTRIC CO. |
| Shared Package | |
| ML19276F851 | List: |
| References | |
| SECY-78-26, NUDOCS 7904120374 | |
| Download: ML19276F853 (3) | |
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3 JUL 2 5 577 Dr. Glenn G. Sheraced, Manager Safety and Licensing General Electric Ccmpany 175 Curtner Avenue San Jose, California 95125
Dear Dr. Sheracod:
Your letter of April 1,1977 to Chairman Rcwden has been referred to me for response.
Careful attention has been given to your concerns that the staff has been overly conservative in its interpretation of' Appendix K and Section 50.46 of 10 CFR Part 50 but I have concluded, for the reasons discussed belcw,. that the staff has. acted in a reason-able manner under the circumstances.
In any event,-it does not appear that policy guidance from the Ccmmission would be the appropriate
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vehicle for the changes you request.
The NRC appreciates your desire to reduce licensing delays and wel-comes suggestions in this regard.
In additicn, however, it must be recognized that Appendix K was the result of a long and detailed rule-making hearing and the staff is required to fully apply its provisions in the licensing of reactors.
In particular, Section 50.46 requires that ECCS calculations must be in acccrdance with an approved evalua-tion model as detennined by Appendix K. Tne ameliorating provision of Section 50.35(a)(2), which you cite in your letter, does not vacate the requirements of Section 50.46 and therefore does not provide a permis-sible alternative in the licensing process.
In any event changes in the way Appendix K is applied cannot be made by policy statement but must be made by a rulemaking to this effect.
In your letter you indicate that: the NRC staff has fcund it necessary to interrupt licarsing proceedings when changes to the. ECCS performance evaluation models are identified and you mention delays in hearings in..
two cases.
In recent instances involving applicatien oi the GE models in 1icensing proceedings, the changes to which you refer were actually errors in the GE models, errors in programming the models into the computer program, or errors in input data.
It is our understanding that the correction of these errors, although relatively simple, would result in higher calculated peak clad temperatures.
In addition, the amount of time involved to correct the errors wculd be small.
5 Encicsure "A" 7904120 g
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Dr. Glenn G. Sherwood Althcugh this was expected to be true, in some instances the. vendor and applicant have joi.itly sought to make additier.al changes in other aspects of the model to offset the penalty incurred due to correcticn of the errors.
The choice of this approach has recuired additional time for documentatien and justificatien of the proposed changes to assure a ccmplete and accurate basis for licensing.
In these cases the staff has provided timely review and approval of the preposed revisions con-sistent with certain procedural limitations imposed by the regulations.
For example, the existence of such errors must be brought to the atten-tion of the various Atomic Safety and i.icensing Boards befora which construction permit applications are pending.
The record of the pro-ceeding must also be corrected, which may take some time, to reflect that the basis for licensing, i.e., conformance with Section 50.46, is still valid after the correction of all errors and incorporation of other proposed changes in the model. Determinations by the staff, as suggested in your letter, that their conclusions regarding issuance of construction
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permits.would not be artered is not an accectable alternative to the full and complete disclosure of all reTevant information to the Scards, who are.._
vested with the authority to grant or deny licenses-In this manner, also, is the public's right and ability to be informed and participate ~~
in the licensing process protected.
Your letter also indicates a concern regarding the need to recalculate the ECCS performance for individuai plants when the evaluaticr. models are revised to correct errors and other preposed changes.
Specifically, you. refer to cases where both GE and the staff were in general agreement that the net effect would be less than 20"F or would not result in cal-culated peak clad temperatures in excess of 2200 F.
Again, while there have beertsuch instances, it must also be recognized that.the staff.is-not at liberty to arbitrarily substitute its technical judgement for conformance to the regulations, particularly when that judgement is
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based on generalized sensitivity studies and the use of parameters which are assigned typical values. Under these circumstances, the staff has required that the estimates of clad temperatures be verified by a recalculation for at least one break (the worst case break) using a ccdel corrected to wholly conform to 5~ecti~on 50.6.
Inis ver1ncation, by an actual, computer run of the approved evaluation modei, establishes the required minimum compliance with the regulati~ ens for each carticular plant-involved.
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In summary, my review of the staff's actions in implementing Section 50.46 and Appendix K to 10 CFR Part 50 does not lead me to share your concerns.
Centrary to being overly restrictive, it appears that the staff has been both reasonable and responsive to the particulari:ed needs of individual acplicants while assuring that licensing actions proceed in accordance 6
Enclosure "A"
.3,-
Dr. Glenn G. Shersced.
with the applicable regulatiens. As I have already mentioned, a rule-making would be required to make substantive chances in the way Appen-dix K is applied.
If GE cheeses not to cursue ruleTaking, the imC will continue to make whatever efforts it can within the limits of Appendix K to minimize any potential licensing delays.
In addition, should the HF.C initiate a reevaluation of Acpendix K in the futura, your c:=ents will be fully considered at that time.
Sincerely, (Signed) Las Y. C3583'1 Lee V. Gossick Executive Director for Operati,ons
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7 Enclosure "A"