ML20247M452

Forwards Request for Addl Info Re Reactor Defueling.Info Needed within 30 Days of Ltr Date

ML20247M452
Person / Time
Site:	Fort Saint Vrain
Issue date:	07/25/1989
From:	Heitner K Office of Nuclear Reactor Regulation
To:	Robert Williams PUBLIC SERVICE CO. OF COLORADO
References
TAC-73124, NUDOCS 8908020108
Download: ML20247M452 (5)

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July '25, ' 1989 g< .

c Docket No. 50-267, Mr.. R. 0.. Wil'liams, .Jr.

Senior-Vice President, Nuclear Operations Public Service Company of Colorado Post Office Box 840-Denver, Colorado 80201-0840-

Dear Mr. Williams:

SUBJECT : FORT ST. YRAIN DEFUELING ANALYSIS'(TAC NO. 73124)

The. staff is conducting a. preliminary review of the proposed defueling of Fort St.'Vrain. Since your defueling Safety Analysis Report (SAR) is not finalized, we have based this review on material presented by Public Service Company of Colorado (PSC) at the meetings held March 8 and July 17. 1989 With the staff.

As part of this review, the staff requests additional information as described in'the enclosure. Please provide this information within 30 days of the date of this letter. If this information is provided by your defueling SAR within this period, reference to your defueling SAR is acceptable.

The information requested in this letter.affects fewer than 10 respondents; therefore 0MB clearance is not required under P.L.96-511.

Sincerely,

/s/

Kenneth L. Heitner,' Project Manager Project Directorate - IV Division'of Reactor Projects - III, IV,LV and Special Projects Office of Nuclear Reactor Regulation

Enclosure:

As stated cc w/ enclosure:

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NUCLEAR REGULATORY COMM'SSION

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%, p July'25, 1989 Docket No. 50-267;

! ' Mr. R. O. Williams, Jr.

Senior Vice President, Nuclear Operations Public Service Company of Colorado Post Office' Box 840-Denver, Colorado 80201-0840

SUBJECT:

FORT ST. VRAIN DEFUELING ANALYSIS (TAC NO. 7? 24)

The staff is conducting a preliminary review of the proposed defueling of Fort '. ' . Vrain. .Since your defueling Safety Analysis Report (SAR) is not finalized,-.we have based this review on material presented by Public Service Company of Colorado (PSC) at the meetings held March 8 and July 17, 1989 with the staff.

As part of this review, the staff requests additional information as described' in the enclosure. Please provide this information within 30 days of the date of this letter., If'this information is provided by your defueling SAR within this' period, reference to your defueling SAR is acceptable.

The-information requested in this letter affects fewer than 10 respondents; therefore OMB clearance is not required under P.L.96-511.

Sincerely, R41.%k Kenneth L. Heitner, Project Manager Project Directorate - IV Division of Reactor Projects - III, IV, Y and Special Projects Office of Nuclear Reactor Regulation

Enclosure:

As stated cc w/ enclosure:

See next page 4

- - -_-_- _ _______ _ _ _ _ - i

Mr. R. O. Williams, Jr.

i. Public Service Company of Colorado Fort St. Vrain CC:

Mr. D. W. Warembourg, Manager Robert M. Quillen, Director Nuclear Engineering Division Radiation Control Division Public Service Company Department of Health

of Colorado 4210 East lith Avenue l P. O. Box 840 Denver, Colorado 80220 L.

Denver, Colorado 80201-0840 l

Mr. David Alberstein, Panager Mr. Charles H. Fuller Fort St. Vrain Services Manager, Nuclear Production GA International Services Corporation and Station Manager Post Office Box 85608 Public Service Company of Colorado San Diego, California 92138 16805 Weld County Road 19-1/2 Platteville, Colorado 80651 Mr. H. L. Brey, Manager Nuclear Licensing and Resource Mr. P. F. Tomlinson, Manager Management Division Quality Assurance Division Public Service Company of Colorado Public Service Company of Colorado P. O. Box 840 16805 Weld County Road 19-1/2 Denver, Colorado 80201-0840 Platteville, Colorado 80651 Senior Res1 dent Inspector Mr. D. D. Hock U.S. Nuclear Regulatory Comission President and Chief Executive Officer P. O. Box 640 Public Service Company of Colorado Platteville, Colorado 80651 Post Office Box 840 Denver, Colorado 80201-0840 Kelley, Standfield & 0'Donnell ATTN: Mr. J. K. Tarpey Comitment Control Program Public Service Company Building Coordinator Room 900 Public Service Company of Colorado 550 15th Street 2420 W. 26th Ave. Suite 100-D Denver, Colorado 80202 Denver, Colorado 80211 Regional Administrator, Region IV U.S. Nuclear Regulatory Comission '

011 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76011 Chairman, Board of County Commissioners of Weld County, Colorado Greeley, Colorado 80631 Regional Representative Radiation Programs Environmental Protection Agency 1 Denver Place 999 18th Street, Suite 1300 Denver, Colorado 80202-2413

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, Enclosure l'

' REQUEST FOR APPITIONAL INFORMATION CONCERNING REACTOR DEFUELING FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLORADO DOCKET N0. 50-267'

1. The staff has replotted your curves of K-Effective vs. Boronation ;

presented at the March 8, 1989 meeting. The staff plot on page 2 shows.

K-Effective vs. Number of' Regions Defueled.

. Simple extrapolation of your data approaching the case of zero regions cefueled shows a wide range of results for K-Effective. The total spread of the predicted value is greater than 0.05. Ideally the medel should predict only.cne value since boronation has no effect before defueling. j begins.

The staff is concerned that the spread in K-Effective. is iue to model errors. Please provide a full evaluation of these errors or demonstrate that your calculations are consistent for zero regiuns defueled. This evaluation should address any further methods that.may be used te reduce errors. The evaluation should provide a worst case estimate of K-Effective vs. Number of Regions Defueled for the prcposed boronation scheme (12 pins).

2. 'During defueling, the boronated dumny blocks provide reactivity control in conjunction with the control rods. Evaluate this proposed reactivity centrol method against Design Criterion 27. Redundancy of Reactivity Control, in the FSV FSAR'(Appendix C, Page C.27-1).

.Your evaluation should address credible errors in your model's ability to predict K-Effective noted in Question 1. It should also address credible errors in providing the correct boron loading to the' dummy fuel blocks, and action to be taken if defueling shutdown margins are not met after defueling a specific region.

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