ML20056C500

Presents Comments & Recommendations Re GE Generic Power Uprate Program & Proposed 5% Power Increase for Fermi-2

ML20056C500
Person / Time
Site:	Fermi
Issue date:	08/31/1992
From:	Zuber N Advisory Committee on Reactor Safeguards
To:	Catton I Advisory Committee on Reactor Safeguards
References
ACRS-CT-2040, CT-2040, NUDOCS 9306240281
Download: ML20056C500 (5)

Text

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August 31, 1992 1

l MDORANDEM 'IO: I. Catton, Chairman, ,

Thermal-Hydraulic Phenomena Subccanittee FROM: N.' Zuber, ACRS Consultant i

SUBJECT:

ACRS Thermal-Hydraulic Phenomena Subccanittee Meeting:

GE Generic Power Uprate Program / Fermi Unit 2 Power Increase August 18, 1992, Bethesda, Maryland This memorandum presents my comments and reccanendations concerning the General-Electric (GE) generic power uprate prcgram and the proposed 5% power increase:  ;

for Fermi-2. It is organized in two sections: Section A addresses the power uprater Section B deals with the generic problem of code documentation.-

A. Power Uprate Fu,-~ -- i by GEl/IEco Ccanents l

In my memorandum of April 7, 1992, I noted four concerns related to GE/ I DECO presentations of March 26, 1992. These concerns'have been addressed I in a satisfactory manner at the present (August 18,.1992) meeting.

Specifically:

1 Effeet of Radial Power Profile on Spray Penetration Although calculations.have not been performed with the TRAC-3-D  :

code to determine the effect of a flatter power profile on spray-J 3 g(){ _ penetration, I accept GE's. position that these calculations are . i not needed (foria 5% power increase) because the'ECC system.has sufficient safety _ margin to acu- . Mate an increase of 15%.

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DES.IGNATED ORIGINAIi 9306240281 9208311 PDR ACRS l D' l

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'l August 31, 1992 fl. Zuber to I. Catton ACRS T-H Subconmittee Meeting, 8/18/92 A. Power Ucrate Proposed by GE/ DECO, Continued

2. Core Power Stability l

I agree with fiRR's position that the stability problem should be addressed and resolved as a generic issue, and not in the context of a 5% power increase. I understand that the power / flow stabili-ty problem will be the topic of the T-H Suhr=nittee meeting in September.

3. Steam Flow and Heat Balance Calculations At the March 26 meeting, GE's discussion of steam flow and heat balance calculations was not very clear. The explanation provi-ded at the August 18 meeting was both clear and satisfactory.

4. Core Water Invel Calculations of feed water transients discussed by GE at the March' meeting indicated a large (5 feet) decrease of water level in the vessel. This was of some concern because it did not seem to be a realistic value.

In addressing this concern, GE noted that the results presented-in March were erroneous. ! Jew calculations performed for Fermi-2 indicate a level decrease of only one foot. I find this new value realistic and acceptable.

August 31, 1992 N. Zuber to I. Catton ACRS T-H Subcountittee Meeting, 8/18/92 A. Power Uprate Promsed by GE/ DECO, Continued Conclusions and Recmmendations

-The concerns and questions raised during the two meetings (Mardt 26, 1992 and August 18, 1992) were addressed by GE/ DECO and by the staff in a pro-fessional and satisfactory manner. I found their responsiveness and co-operative spirit nest gratifying.

-The program was well organized and managed by both parties, that is, by the industry and by the staff.

-The requested 5% power uprate is well within safety margins available in present plants. It is also within the " noise" level of computer code capa-bilities.

Consequently, it is my judgement that

1. GE's generic power uprate program should be app'toved, and

2. Fermi-2 should be granted the requested 5% power increase.

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August 31, 1992 '

N. Zuber to I. Catton

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ACRS T-H Subcomittee Meeting, 8/18/92 i

B. Availability of Cbde humorttatie During the meeting GE mentioned calculations performed with a computer code: ,

(SHEX) with which I was not familiar. Although these calculations were only  ;

peripheral to the main topic of the meeting, I am taking this opportunity .

to address briefly the problem of code documentation, inasmuch as it is a generic issue.

Comments and Reconmendations ,

Thermal-Hydraulic and severe accident' issues are most often addressed'and' resolved by means'of computer code calculations. . Frequently, the results of

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1 such calculations are presented and discussed during a meeting without the availability of code documentation.because i

1) The reports have not been written (or updated) and/or -a

2) The reports are proprietary. g

~Thus, any judgements made at the tine of the meeting must'in large part be.

based upon belief and. faith, rather than on documented facts and evidence, . l

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and a sound technical review and assessment of the results cannot.be made. )

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-1 It is true that' the appropriate code documents are eventually _made available to the ACRS. However, the. time which elapses between the' initial' discussion and access to.' supporting code documentation sometimes amounts.to many. nonths.

At_'best, such' delays are counterproductive to a timely, efficient, and. sound technical review process.

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August 31, 1992 N. Zuber to I. Catten ACRS T-H Subcommittee Meeting, 8/18/92 B. Availability of Code Documentation, Continued Coments and Recomendations, Cont'd.

Consequently, I would recommend that whenever the industry and/or staff pre-sent and discuss the results of calculations performed by a computer code, they should make available to the ACRS the documents which descrite the par-ticular version of the code. This should be done before or at the time of the presentation.

I realize that code developers and managers will find this recmmendation- .

distressful and will, therefore, find numerous reasons to oppose it. How-ever, I believe that in a regulatory agency, technical issues nust be ad-dressed and resolved in a traceable and accountable manner.

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