ML20003G364
| ML20003G364 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 12/23/1980 |
| From: | Swart F PUBLIC SERVICE CO. OF COLORADO |
| To: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| FOIA-81-95 IEB-79-14, P-80442, NUDOCS 8104290203 | |
| Download: ML20003G364 (3) | |
Text
.
4
~
Public service company otP cdicImee i
j 12015 East 46th Avenue, Suite 440; Denver, CO 80239
,)
i i
x+J December 23, 1980 To ADM/DMB:
Fort St. Vrain POR Unit No. 1 LPOR P-80442 NS DWIT g,\\ t % / 4 AD B
[Y [
Mr. Karl V. Seyfrit, Director
[h[h
((
Nuclear Regulatory Commission
\\
Region IV L,
APR.?
Office of Inspection and Enforcement 611 Ryan Plaza Drive
}g 4 OOI A 2 S n,% @l4m i %d or Suite 1000 Arlington, TX 76012 ou s?
ui
Subject:
Safety Rela.
1 ping System Audit
References:
PSC Letter P-79161, dtd 08/01/79 PSC Letter P-79198, dtd 09/04/79 PSC Letter P-79238, dtd 10/15/79 PSC Letter P-79292, dtd 12/04/79 PSC Letter P-30029, dtd 02/15/80 PSC Letter P-80091, dtd 04/23/60 PSC Letter P-80194, dtd 06/30/80 PSC Letter P-80282, dtd 08/25/80 PSC Letter P-80380, dtd 10/28/80
Dear Mr. Seyfrit:
This final supplemental reply to I&E Bulletin 79-14 is to ccmplete PSC's October 15, 1979 commitment to report in summary form discrepancies identified and corrective actions taken associated with the Fort St.
l Vrain Seismic Review Program.
In addition, this letter constitutes the first report to PSC's October 28, 1980 commitment to report on the I
status of PSC's seismic redocumentation program which is to be submitted on a semi-annual basis.
j PSC has completed the field audit (inspection) of all accessible safety related piping ecual to or greater than 21/2 inches in diameter and all i
accessible seismic piping supports which includes the American Institute I
of Steel Construction (AISC) portion of the hanger structure.
In conjunction with this field audit program, the plant as-built configuration I
was reviewed and assessed for compliance with the documentat.on which was the basis for the original seismic analysis.
As a result of this i
review, PSC generated and completeo 1108 craft actions for the purpose of restoring the originally intended design configuration per the provisions of I&E Bulletin 79-14, the referenced PSC letters to the NRC and the SDCC procedures of which the NRC Resident Inspector is on distribution.
8104290 4 e
4~
P-80442 Page 2 December 23, 1980 The most common type of corrective actions required during the program have been:
Repair of undersized welds Removal of non-documented attachments to the hanger structure Modification of "U"-holts Restoration of hanger structures to intended configuration It should be noted that the vast majority of the items requiring corrective action wre products of initial construction and that the presently existing PSC procedures are adequate to prevent the reoccur ence of similar physical and documentation discrepancies.
Based upon the completion of the aforementioned field audit and craft action program, it is PSC's conclusion that Fort St. Vrain Unit No.1 is now in ccmpliance with the intent of I&E Bulletin 79-14.
PSC's follow on redocumentation prcgram which includes the drafting, quality assurance verification and analytical analysis of the as-built drawings of the Class I piping. systems and seismic pipe restraints is continuing.
This redocumentation program is scheduled for completion in mid-1983.
There are currently 103 piping analysis packages containing 290 seismic piping isometrics and 1189 siesmic piping restraints in the-analysis phase of the redocumentation program.
The Seismic Redocumentation Program at Fort St. Vrain has gone through a continuing evolut'on since its inception.
As a result of this evolutionary process, a restatement of our analytical analysis techniques and reanalyzed stress evaluation criteria is warranted.
The analysis phase of the redocumented program utilizes computerized analytical methods for determining stresses in the Class I 21/2 inch diameter and larger piping and pipe supports which are consistent with the methods previously used for Class I,10 inch diameter and greater piping.
The calculated operational basis earthquake (08E) stresses obtained frca the analysis redocumentation program for the Class I piping and pipe supports is being initially evaluated by comparing this stress value to the FSAR allowable OBE stress limitations, and then by comparing double this value to the FSAR design basis earthquake (DBE) allowable stresses.
This evaluation criteria is conservative relative to the FSAR and is identical to the criteria used to evaluate the original analysis of the 10 inch diameter and greater piping at Fort St. Vrain.
If tne calculated piping or pipe support stresses do not meet the aforementioned criteria, PSC will within 30 days 1) take the corrective action necessary to satisfy the criteria or 2) reanalyze the piping or pipe support to obtain calculated DBE stresses as allowed by FSAR for coccarison to the FSAR DBE stress allowables.
In the event that options 1 and 2 above cannot be accomplished within 30 days or the DSE reanalysis concludes piping system impairment, PSC will envoke the necessary Technical Specification action statements.
Based on the corrective actions taken during the recently completed audit / craft action program and on the results of analysis performed bot,h prior to and during the audit / craft
1
./.
P-80442 Page 3 December 23, 1980 action program, PSC does'not anticipate identifying any piping system impairments during its redocumentation program.
In addition, the sensitive systems, those systems which must remain operable in order to protect the health and safety of the public in the event of Design Basis Accident Number One as defined in the FSAR, are being redocumented on a priority basis.
If there are any questions, please contact this office.
Very truly yours,
(
,6 d & CM j
Frederic E. Swart Nuclear Project Manager FES:pa i
I t
i I
.