ML20041C124
| ML20041C124 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 01/04/1982 |
| From: | Brey H PUBLIC SERVICE CO. OF COLORADO |
| To: | Jay Collins NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| P-82004, NUDOCS 8202260233 | |
| Download: ML20041C124 (3) | |
Text
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Eb-969
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public Sen' ice Company F CdleImde V8 January 4,1982 Fort St. Vrain Unit No.1 P-82004
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Mr. John T. Collins, Regional Administrator k -- t g%
Nuclear Regulatory Commission Region IV Office of Inspection and Enforcement u,1#
611 Ryan Plaza Drive Suite 1000 ev, rlington, TX 76012
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Subject.
Seismic Piping System Il
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References:
PSC Letter P-80442, dtd 12/30/80 2
56Ny -Q i PSC Letter P-81019, dtd 01/20/81 f,3<3 a' 3f PSC Letter P-81172, dtd 06/18/81 g
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' This supplemental reply is to continue P.S.C. 's January 20, 1981 comitment to report the status of the Fort St. Vrain Seismic Piping System Redocumentation Program on a semiannual basis.
PSC's redocumentation program consists of the drafting, quality assurance verification and analytical analysis of the as-built drawings for the Class I piping systems and seismic restraints. This program status report includes both the 21/2" and Larger and 2" and Under Class I piping systems.
The drafting activities and Quality Assurance verification has been completed on all of the Class I
isometric drawings and pipe support drawings. The Quality Assurance activity generated 132 craft-actions (CA's) of which 121 have been completed by construction.
These CA's are being processed in a manner similar to that utilized for the CA's that were generated in the Audit phase of the seismic project for I & E Bulletin 79-14. The two most predominant types of Quality Assurance craft actions are those associated with undersized welds and modification of "U"-bol ts both of which are being identified during the verification of the AISC portion of the support structures.
.f 8202260233 820104
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PDR ADOCK 05000267 t
report, P-81172 stated that subsequent processing of L
PSC's.last
' documents; prior to analysis redacumentation was. necessary due to A
recent. completion of: the definition - of : structural evaluation criteria. This processing consists of a review of all. of the 2 1/2"'
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and Larger-~ Class I as-built - support ; drawings to ensure that the defined criteria has been consistently ' applied.. It also -includes a
. review.of the piping analysis packages to detemine the boundaries and overlap zones for the analysis packages.
This; review.has identified 84. craft actions, 75 of which are associated with the finalized structural criteria and 9 of which install supports for piping.. analysis boundary definition. These craft actions are being processed in a manner similar to the ' Audit and -Quality Assurance craft actions.
Analysis has been. completed on 153 of the 190 low energy 2.1/2" and larger piping analysis packages and on 451 pipe supports.
The completion. of one or more' piping -analysis packages is required to detemine the.-loads for a given : pipe support, therefore the pipe support analysis will necessarily lag behind the piping analysis.. To date, the redocumentation program has identified 97_ cases requiring corrective action. These cases' are being corrected by preparing and implementing a craft action within the ^,0 day time period specified in our procedures as described.in P-80442, dated December 30, 1980.
n The majority of these cases requiring corrective action involve U-s bol ts, anchor bolts and base plates. All three of these items are being identified due to expansion and amplification of the: pipe support analysis criteria..The use of a simplified conservative base plate flexibility analysis versus finite element analysis accounts for the-anchor bolt and base plate corrective actions..Several of the corrective actions involving base plates have been re-analyzed by PSC using finite element analysis, with the results indicating that a
corrective action would not be required if this analysis method had been used.
The Class I high energy piping systems at Fort St.LVrain were originally analyzed using computerized analytical methods consistent with the methods being-applied by PSC to the low energy 2 =1/2"r&-
Larger Class I piping systems as part of its -redocumentation program.
l-The resul ts of the audit conducted per I & E Bulletin 79-14, which l
were verified during the Quality Assurance phase.of the redocumentation program, indicate that the.as-built configuration of-the high energy piping systems, confoms to the. original. design documents.
Since the s high energy piping systems have already been :
analyzed using computerized analytical methods and
-since the documentation used as. input to this analysis has been verified, PSC has excluded the high energy piping systems from the analysis phase-of its redocumentation program.
The pipe supports _ in the.high energy systems are also being excluded since their - as-built configuration has been verified and because the principal discrepancies being found
~ in the low energy pipe supports have not been found in the high energy supports.
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~ The remaining 2"
and -Under analysis is being perfenned in-parallel with the 21/2" and larger analysis,.primarily because: of i
interfaces.between the small and large bore piping. The remaining 2"
'and under craft actions are being completed in parallel with the 2-1/2" and larger portion of the Seismic Redocumentation Program. The j
schedule completion date for PSC's redocumentation program is mid-1983.
Very truly yours, f)%
H. L. Brey,' Manager Nuclear Engineering Division HLB /RLC/deh i
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