ML20154N491
| ML20154N491 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 09/19/1988 |
| From: | Wilson R GENERAL PUBLIC UTILITIES CORP. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| IEB-79-02, IEB-79-14, IEB-79-2, NUDOCS 8809290323 | |
| Download: ML20154N491 (5) | |
Text
GPU Neclear Corporation a
One Upper Pond Acad Qgggf Pars'ppany, New Jersey 07054 201 4 16 7000 TELEX 136-482 September 19, 1988 Writer's Direct Dial Nurnber:
5000-88-1637 U.S. Nuclear Regulatory Commission Attention:
Document Control Desk fiail Station PI-137 Washington, D.C.
20555 Gentlemen:
Subject:
Oyster Creek Nuclear Generating Station (OCNGS)
Docket No. 50-219 Seismic Floor Response Spectra The purpose of this letter is to summarize and describe GPUN's effort to develop updated seismic floor response spectra for the Oyster Creek Reactor Building and how this effort impacts our commitment to have all systems which f all within the scope of IE Bulletins 79-02 and 79-14 meet design criteria by the end of the cycle 12 refueling outage.
The cycle 12 refueling outage is currently scheduled to Commence on Oct. 15, 1988 with twelve to fourteen week duration.
In July of 1987, GPUN first met with the NRC staf f in Bethesda, fiaryland to discuss the development of a new, more technically appropriate seismic floor response spectra which would eliminate past confusio,15 concerning the Oyster Creek seismic design basis and would maintain consistency for future analyses.
At that seting GPUN stated that the methodology (i.e., Soil Structuro Interaction (SSI) L use of SEP ground spectra) for the new floor response spectra would be reviewed under 10 CFR 50.59 and the new spectra woyld be applied to the current reanalysis being undertaken for IE Bulletins 79-02 ane 79-14.
GPUN and the NRC have agreed that a more technically appropriate floor response spectra utilizing a state of the art technique would be beneficial.
Altnough the developnent of the floor response spectra is being implemented under 10CFR50.59, we have oeen and will continue to be in close contact with the NRC staf f for its guidance and concurrence.
Follow-up meetings were held with the staff on September 3, 1997. December 21, 1987, liarch 8,1983 and fiay 23, 1983.
Correspondence in response to NRC questions has been submitted at various times during the past year.
In response to the staff's letter of December 15, 1987, GPUN 1s currently developing confirmitory site specif1c ground spectra with Westnn Geophysics Corporation in an ef fort to verify the acceptability of using the SEP ground spectra in the SSI analysis. NRC staff and their consultant also audited the newly developed floor response spectra methodology at the offices of GPUN's consultant, URS/Blume & Associates Engineers on November 17 and 13, 1987.
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' Although agreement with the NRC regarding the new floor response spectra is expected, GPUN had anticipated that the issue would have been resolved by this a
time. GPUN had previously committed that all systems, which fall within the scope of IE Bulletins 79-02 and 79-14, would meet design criteria by the end l
of the cycle 12 refueling outage. Rather than continue to design support upgrades for all elevations using the original seismic criteria, it was decided by GPUN that utilization of the new floor response spectra was more appropriate.
While GPUN aiticipates satisfactory resolution of the issues surrounding the new spectra with the NRC staff by the end of the Cycle 12 refueling outage, we nevertheless recognize the possibility that resolution might not be achieved by that time, or that the resolution may increase the acceleration values of the new floor response spectra.
Should either of thesJ situations occur our commitment to have all systems meet design criteria by the end of the cycle 12 i
refueling outage, would not be fully realized. Ne consider this to be acceptable, however, for the following reasons:
The methodology used to generate the new floor response spectra is consistent with t u applicable sections of the proposed Standard Review Plan, NUREG's and Regulatory Guides.
This methodology represents a censiderable technical improvement over the methodology used he the previous,eismic analyses.
l All piping systems will satisfy ANSI B31.1 design criteria by restart i
from the cycle 12 refueling outage based on the new floor response 6
spectra.
Tho majority nf the piping models (approximately 700 currently satisfy ANSI B31.1 allowables based on the original seismic criteria.
The rema*ning piping nodels (approvinately 30%) currently satisfy operability criteria when using the original seismic criteria.
The majority of supports (approximately 86%) currently satisfy the FSAR design criteria. is a pie chart for IEB 79-14 support
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upgrades as of September 9, 1988, which shows greater detail.
i All support upgrades based on the new floor response spectra will be completed by restart from the cycle 12 refueling outage.
It should be noted that, with only several exceptions, all supports which are being upgraded have been designed to the greater load f rom either the new or original seismic criteria.
The majority of IE Bulletin 79-02 anchorage inspections or epgrades (approximately 00%) has been documented. Attachment 2 is a pie chart for 79-02 anchorage inspections as of September 9, 1988, which shows L
greater detail.
All IEB 79-02 anchorage inspections or upgrades based on the new floor response spectra will be completed by restart from the cycle 12 refueling outage.
Should resolution witn the NRC regarding the floor response spectra cause an increase in accelerations which exceed tne response spectra l
currently being used, the few remaining upgrades would be completed, in accordance with an Integrated Schedule.
3-Public health and safety is not compromised.
In fact, safety margins are now more clearly defined with the new floor response spectra.
Of the 691 pipe supports covered by the IE Bulletins, only 28 upgrades required by the original seismic criteria would not be performed since these upgrades are not necessary when considering new floor response spectra.
However, eight upgrades identified by using the new seismic input will be performed during the upcoming cycle 12 refueling outage.
We are currently in the process of resolving questions raised by the NRC staf f during our last meeting on liay 23, 1988. We plan to meet with the staff in the near future to discuss our response to the questions and any comments you may have concerning this letter.
If there are any questions regarding this letter which you need to discuss prior to the meetuig, please con:act Mr. iiichael W. Laggart at (201)316-7968.
Ilery truly yours, n 6~--
R. F. Wilson Vice President Technical Functions 1
RFW/ML/pa(7276f) cc: fir. William T. Russell, Administrator i
Region !
U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA.
19406 NRC Resident liispector l
Oyster Creek Nuclear Generating Station Forked River, N.J.
08731 fir. Alex Dromerick U.S. Nuclear Regulatory Commission fiall Station Pl.137 Washington, D.C.
20555 i
i i
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4 79-14 SU'~ ORT UPGRADES STATUS AS OF SEPTEMBER 9,1988
@ AdOOFDUM 7tsx ll
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=am ae m AwUFED :numA s:3 A
ANAD3tR*WT) s,q.4 m
23%
- 14%
k me DOLS NOT INCLUDE 25 SUPPORTS
- 13. %
"t!=tTiarasP ME*:
T S
OeTS e
79-02 ANCHORAGE INSPECTIONS STATUS AS OF SEPTEMBER 9,1988 l
W/D AlXXTDONAL NSFtL;IsON 392 56.3 %
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A..
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\\s:::
b::?:::I my TO 8~
t 1986 MN
'~'
99 y
14.2 %
67
]
~
9.6 %
/
CO@t.ETED N
,.N' W
COWLETED N m
l 91 g
13.1 %
6.8%
- DISPOSITION MEANS THAT THE ANCHORAGE WAS EITHER INSPECTED OR UPGRADED TO SATISFY HIGHER LOADS.
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