ML19344E555
| ML19344E555 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 07/07/1980 |
| From: | Swart F PUBLIC SERVICE CO. OF COLORADO |
| To: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| IEB-80-11, P-80198, NUDOCS 8009020221 | |
| Download: ML19344E555 (3) | |
Text
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CENTRAL FZLES PDR:HQ Public service company oe 4Pp NSIC July 7, 1980 e
Fort St. Vrain Unit No. 1 P-80198 Mr. Karl V. Seyfrit Director Region IV Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76012
Subject:
Masonry Block Walls Gentlemen:
The following is Public Service Company of Colorado's sixty day response to IE Bulletin 80-11:
Item 1:
Masonry walls that are in the proximity to or have attachments from safety related piping or equipment such that wall failure could affect a saiety related system.
PSC has completed an investigation of all concrete masonry block walls in the turbine and reactor buildings.
A total of 98 masonry walls were reviewed for the potential of affecting safety related equipment during a seismic event.
The walls were divided into the following categories:
A.
Masonry Walls with no potential of affecting safety related equipment 41 walls B.
Masonry walls with potential of affecting safety related equipment 34 walls C.
Walls accessible from one side only that may or may not affect safety related equipment 11 walls D.
Wall totally inaccessible that may or may not affect safety related equipment 12 walls Example. of masonry walls and associated equipment that have no potential of affecting safety related equipment are as follows:
l Wall Number 1 Hydrogen Bottle Storage Room Wall Number 5 North Wall Turbine Oil Storage Room 8009020
Mr. Karl V. Seyfrit July 7, 1980 Page 2 Wall Number 53 Separation wall between the radio chemical laboratory and the counting room.
Examples of masonry walls and the associated equipment with the potential of affecting safety related systems are as follows:
Wall Number 14 & 16 Intermediate masonry walls (missile walls) in the switch gear room separating switch gear equipment Wall Number 39 & 90 South wall of reactor instrument room with safety related cable trays adjacent to the wall Examples of masonry walls that are accessible from only one side are as follows:
Wall Number 68 Pipe chase with safety related cable tray near wall Wall Number 74 Pipe chase which has safety related two inch and under piping near wall Examples of masonry walls that are totally inaccessible are as follows:
Wall Number 69,70 & 71 Wall located inside the liquid waste & gas waste facility A wall number was assigned to each masonry bleck wall in order to uniquely identify it for audit and calculation purposes.
1 The majority of the attachments to the concrete masonry block walls are items such as electrical conduit and Class II, two inch and under pipe hangers.
These items input very little force into the wall during a seismic event compared to forces due to large bore piping. As part of our audit procedure for our small and large bore piping programs (IE79-14), we have been removing all Class I pipe hangers from masonry block walls.
Item 2:
Program for the reevaluation of the masonry walls PSC in its audit of the concrete masonry block walls has, for all walls that are safety related and accessible. prepared sketches of the wall showing the location of all piping, conduit, junction boxes, cable trays, mechanical equipnent, etc. that is attached to the wall.
From these sketches it is our intent to determine loads that this equipment would impact into the wall during a seismic event.
These loads will be used to evaluate the adequacy of the masonry wall.
Each masonry block wall that is accessible and that has the potential of affecting a safety related system will have its own analysis to determine the adequacy of the wall.
The estimated completion date for the reanalysis is November 3,1980.
If, in the course of the reanalysis of the safety rt: lated masonry block walls, problems develop with the stresses in the wall such that the wall could have the potential of affecting a safety related system, the wall shall be reinforced to carry the loads used in l
the analysis.
l t
9 Mr. Karl V. Seyfrit July 7, 1980 Page 3 Item 3:
Testing program in the absence of appropriate acceptance criteria PSC has specifications and drawings concerning the materials used in the masonry block walls.
This information includes such items as strengths of masonry block, strength of motar, rebar size and spacing.
Since conservative assumptions shall be used in the reanalysis of the block walls, no testing program of the walls at this time is felt to be required.
Very truly yours, fl
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'm Frederic E. Swart Nuclear Project Manager FES/ RAG:pa e
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