ML20235G758

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Revises Radiation Levels in 860620 Environ Qualification Program Submittal.New Radiation Levels Well Below Radiation Damage Threshold Limit for Electrical Equipment.Corrected Equipment Dose Levels Incorporated in Rev 5 to Updated FSAR
ML20235G758
Person / Time
Site: Fort Saint Vrain Xcel Energy icon.png
Issue date: 09/17/1987
From: Brey H
PUBLIC SERVICE CO. OF COLORADO
To: Calvo J
NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM), Office of Nuclear Reactor Regulation
References
P-87314, TAC-42527, NUDOCS 8709300200
Download: ML20235G758 (3)


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h Public Service ~ 2420 W. 26th Avenue, Suite 1000, Denver, Colorado 80211 e,3; m September 17, 1987 I Fort St. Vrain '

Unit No. 1 P-87314 i

U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 Attention: Mr. Jose A. Calvo Director, Project Directorate IV Docket No. 50-267

SUBJECT:

Revision of Radiation levels in the FSV EQ Program

REFERENCE:

1) PSC Letter, Warembourg to Berkow Dated June 20,1986(P-86435)
2) PSC Letter, Swart to Speis, Dated July 24, 1979 (P-79157)  !
3) PSC Letter, Williams to Calvo, Dated July 22,1987(P-87255)

Dear Mr. Calvo:

Public Service Company of Colorado (PSC) submitted in Reference 1 a summary of the Fort St. Vrain (FSV) Environmental Qualification (EQ) program considerations as they relate to compliance with 10 CFR 50.49. Radiation, one of the qualification parameters, was specified as follows:

Accident 30 Day TID DBA-1 312 Rads DBA-2 414 Rads HELB 12 Rads In subsequent analyses for various other tasks related to EQ of equipment and personnel doses, errors were identified in the previous radiation level analyses for DBA-1 and DBA-2. The previous analyses of these two accidents used a Reactor Building volume that was about 7

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P-87314 Page 2 September 17, 1987 a factor of 2 low. The corrected Reactor Building volume is 4.2 E10 cubic centimeters. In addition, the previously reported cumulative i equipment dose of 312 rads over a 30 day period for DBA-1 was based on a more realistic source term than that described in the FSAR for I DBA-1. The DBA-1 dose calculation in Reference 1 used a realistic fuel failure model to predict the fission product activity released from the core, based on Reference 2, and median PCRV escape fractions based on King furnace tests. A reassessment has been conducted using l the more conservative time - dependent fuel failure model and King furnace PCRV escape fractions discussed in FSAR Sections 14.10, D.1 and D.3.4.

Reanalyses of the EQ program radiation levels for DBA-1 and DBA-2 and a new analysis of the Maximum Credible Accident (MCA, described in FSAR Sec. 14.8), with the above discrepancies corrected, results in the following radiation doses to equipment in the Reactor Building:

Accident 30 Day TID  !

DBA-1 497 Rads DBA-2 279 Rads HELB 12 Rads ,

MCA 31 Rads l These new radiation levels are well, below the radiation damage threshold level for electrical equipment and have been incorporated into the FSV EQ program documentation.

These corrected equipment radiation dose levels have been incorporated into the annual FSAR update (Revision 5) submitted in Reference 3.

If you have any questions on this information, please contact Mr. M.  !

H. Holmes at (303) 480-6960.

Very truly yours W

H. L. Brey, Manager 4 Nuclear Licensing '

and Fuels Division l HLB /JS:bac Attachments

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7 i

P-87314

, Page 3 September 17, 1987

, cc: Regional Administrator, Region IV l Attention: Mr. J. E. Gagliardo, Chief Reactor Projects Branch {

Mr. R. E. Farrell Senior Resident Inspector Fort St. Vrain t

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