ML19337A413
| ML19337A413 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 07/16/1980 |
| From: | Walbridge W SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | Engleken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| Shared Package | |
| ML19337A412 | List: |
| References | |
| IEB-80-11, NUDOCS 8009090813 | |
| Download: ML19337A413 (3) | |
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SACRAMENTO MUNICIPAL UTILITY District O 6201 s street, Box 15830, sacramento, California 95813; (916) 452 3211 July 16, 1980 Mr. R. H. Engelken, Director Region V, Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission
' Suite 202, Walnut Creek Plaza 1990 North California Boulevard Walnut Creek, CA 94596 Docket 50-312 Rancho Seco Nuclear Generating Station, Unit No.1 IE Bulletin 80-11 Masonry Wall Design
Dear Mr. Engelken:
l The subject bulletin, dated May 8,1980, requested informa' ion t
on masonry walls that could affect safety related systems. Attachment 1 provides our response to the program for reevaluating the masonry walls.
I l
This work will be conducted and a final report will be filed l
within the time frame allowed in the bulletin.
t If you require additional information, please contact us.
Sincerely yours, g
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Wm C. Walbridge l
l General Manager i
i Attachment cc: NRC Office of Inspection and l
Enforcement Division of Reactor l
Operations Inspection Washington, D.C. 20555 Sworn to anj subscribed before me this L day of July,1980
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My Commrssson E res November 22,1983 l
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Notary _Publicf AN' ELECTRIC S Y S Tf g S E R V I N G MORE THAN 600,000 IN THE' HEART OF C ALIFO R N I AL O U O Q Q Q Q _ Y h) t
l.i RESPONSE TO I & E BULLETIN 80-11 7 h MASONRY WALL DESIGN 1.
Identify all masonry walls in your facility which are in proximity to or have attachments from safety-related piping or equipment such that wall failure could. affect a safety-related system. Describe-the systems.and equipment, both safety and non-safety-related, associated with these masonry walls. -
Include in your review, masonry walls that are intended to. resist impact of pressurization loads; such as missiles, pipe whip, pipe break, jet impinge-ment, or tornado, and, fire or water barriers, or shield walls. Equipment to be considered as attachments or in proximity to the walls shall include, but is'not limited to, pumps, valves, motors, heat exchangers, cable trays, cable / conduit, HVAC ductwork, and electrical cabinets, instrumentation and controls. Plant surveys, if necessary, for areas inaccessible during normal plant operation shall be perfonned at the earliest opportunity.
Answer: Two areas at the Rancho Seco Nuclear. Generating Station, Unit #1 have reinforced concrete masonry block walls e'id both areas are external to the structures.
1.
Nrea 1 is located at the 40-foot elevation of the Auxiliary Building and is of a three-sided configuration.
It encloses the Nuclear Station Service Transformer Train "B".
No equip-ment, pipes, or safety-related conduit is attached to the walls.
2.
Area 2 is located on the North side of the power block structures.
The safety-related equipment located in proximity of eight foot
.high concrete' masonry, block wall, that possibly could be affected by the wall failure at e the Train "B" Nuclear Service cooling 5.ater heat exchanger and pump, the Cardox Co2 storage unit, the under-ground diesel oil storage tank, and possibly the condensate storage tank.
No equipment is on the wall _ except the conduit for the intrusion alarm system for the area.
2.
Provide a reevaluation of the design adequacy of the walls identified in Item 1 above to determine whether the' masonry walls wil_1 perform their intended function under all postulated loads and load combinations.
In this regard, the NRC encourages the formation of an owners' group to establish both appropriate reevaluation criteria and where necessary, a later confirmatory masonry test program to ' quantify the safety margins
. established ~by the reevaluation criteria (this is discussed further in Item 3 below).i
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a.
Establish-a prioritized program for.m mevaluation of the1 masonry walls.
Provide a description of N -ogyam and a detailed schedule for completion of the reevale W.m F-the categories in the program.
- The completion date of all re <aiu
,n should not be more than 180 days from the date of this Bu;tetin. si higher priority should be
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' nm placed on the wall re:valuatio~ns ~ considering safety-related piping 2-1/2 inches or greater in diameter, piping with support loads due
_to thermal expansion greater than 100 pounds, safety-related equipment CC zweighing 100 pounds or greater, the safety significance of the poten-
.s, tially afrected. systems, the overall loads on the wall, and the oppor-tunity for performing plant surveys and, Lif necessary, modifications in areas ~otherwise inaccessible.- The factors described above are meant to provide guidance in determining wh~at-loads may significantly affect the masonry wall ar alyses.
Answer: The field investigation of the two areas will be completed
- during the week -of July 7,1980. The Area I walls will be analyzed starting July 15, 1980 to verify the structural design of.these walls. Concurrently with the reanalysis, construction documentation will be assembled. This effort for Area I will be complete by August 29, 1980. The Area 2 walls reanalysis' will be started on August 1,1980.
Con-currently, the construction data will be assembled. -This effort will be complete by_ October 1, 1980.
The final report will be prepared and submitted by 180 days from the date of the bulletin.
3.
Existing _ test data or conservative assumptions may be used to just'ify the reevaluation acceptance criteria if the criteria are shown to be conservative and~ applicable for the actual plant conditions.
In the absence of appropriate acceptance criteria, a conformatory masonry
" wall test program is required by the NRC in order to quantify the safety margins inherent in the schedule to justify the reevaluation p.
criteria used in Item 2.
If a test program is necessary, provide your nf co7:nitment for such a program and a schedule for completion of the pro-gram. This test program.should address all appropriate loads (seismic, tornado, missile,etc.).
It is expected that the test program will extend beyond the 180 day' period allowed for the other Bulletin actions.
Submit.the results of the. test program upon its completion.
. Answer:
Justification for the reevaluation criteria will be submitted with the reevaluation rcport within 180 days of the date of the Bulletin received.
Justifications will be based on reference to effective codes and esta-blished standards of practice related to concrete and masonry design typically used throughout the' industry.
It is anticipated that such justification will be cc.nsidered appro-priate, and that a test program will not be necessary, except as required to determine project unique structural properties such as collar joint strength, and any other properties for which construction test data is not available or can not otherwise be determined.
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