ML20106C855
| ML20106C855 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 09/21/1992 |
| From: | Link B WISCONSIN ELECTRIC POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20106C859 | List: |
| References | |
| CON-NRC-92-111, REF-GTECI-A-46, REF-GTECI-SC, TASK-A-46, TASK-OR GL-87-02, GL-87-2, VPNPD-92-313, NUDOCS 9210060384 | |
| Download: ML20106C855 (5) | |
Text
w.
' Electnc POWER COMPANY
-1 231 W PActon PO Evu 20/6. Wmukee W1 $3701 (414)221 2345 -
VPNPD-92-313
-NRC-92-111 September 21, 1992' Document Control Desk HU.S. NUCLEAR REGULATORY COMMISSION Mail Station P1-137 Washington, D.C.
20555 Gentlemen:
DOCKET NOS. 50-266 AND 50-3Q1 FESPONSE TO GENERIC LETTER 87-02. SUPPLEMENT 1 ON SOUG RESOLUTION-OF USI A-46 POINT BEACH NUCLEAR PLANT. UNITS 1 AND 2 INTRODUCTION On February 19,_1987,- the-NRC issued Generic Letter 87-02,
" Verification of Seismic Adequacy of Mechanical'and Electrical Equipment in Operating Reactors, Unresolved Safety Issue (USI)
A-46."
This Generic Letter encouraged utilities to' participate in a generic program to resolve the seismic verification-issues associated with USI A-46.
As a result,:the Seismic Qualification-Utility Group '(SQUG), of-which Wisconsin Electric is a member, developed the " Generic Implementation Procedure <(GIP) for Seismic-Verification'of Nuclear Plant Equipment." _On Mayn22,' 19 92,; the -NRC -
~
Staff issued Generic Letter 87-02,
.pplement 1.
This_' letter constituted the NRC Staff's review of the GIP and included Supplemental Safety Evaluation Report Number 2 (SSER-2)-on the GIP, Revision 2,-corrected on-February 14, 1992.
In Generic Letter 87-02, Supplement 1, the NRC requests that SQUG member. utilities provide, within 120 days, the following information:
1.
A statement of. commitment to use-both the SQUG commitments and the implementation guidance provided'in the GIP as supplemented by SSER-2 for the resolution of USI A-46, 3.
'A plant-specific schedule for implementing the-GIP and submission of a report to the staff summarizing the A-46
-review.
3.
,The detailed information as to procedures rnd criteria ~used to generate the in-structure response spectra to be used for USI A-46.
9210060394 9209bl.
I PDR ADOCK 05000266 I
t 3
P.
PDR k'"
j m nwa>,m-,
e
~. - - - - -...
e.
Document Control Desk September 24, 1992 Page 2 By letter dated August 21, 1992, to Mr. James G.
Partlow, NRR-NRC, the SQUG clarified that the 120 day response period expires on September 21, 1992.
This letter responds to the Staff's request for Point Beach Nuclear Plant.
ROMMITMENT TO GIP GIP Commitments Wisconsin Electric commits to the SQUG commitments set forth in the GIP in their entiroty, where " GIP" refers to GIP Revision 2, corrected on February 14, 1992, to resolve USI A-46 at Point Beach Nuclear Plant (PBNP), Units 1 & 2.
This commitment includes the clarifications, interpretations, and exceptions identified in SSER-2 and clarified by the August 21, 1992, SQUG letter responding to SSER-2.
This letter is included as Attachment A.
The GIP, as evaluated by the Staff, permits licensees to deviate from the SQUG commitments embodied in the commitment sections, provided the Staff is notified of substantial deviations prior to implementation.
Wisconsin Electric recognizes that the Staff's position in SSER-2 is that if licensees use other methods that deviate from the criteria and procedures as described in SQUG commitments and in the implementation guidance of the GIP without prior NRC Staff approval, the method may not be acceptable to the staff and, therefore, may result in a deviation from the provisions of Generic Letter 87-02.
GIP Guidance Wisconsin Electric generally will be guided by the remaining (non-commitment) sections of the GIP, i.e., GIP implementation guidance,
.which comprises suggested methods for implementing the applicable commitments.
Wisconsin Flectric will notify the NRC'as soon as practicable, but no later than the final USI A-46 Summary Report, of significant or programmatic deviations'from_the guidance portions of the GIP, if_any.
Justification for any such deviations will be retained on-site for NRC' review.
At this time, no significant or programmatic deviations are anticipated during the implementation of the GIP guidance.
IN-STRUCTURE RESPONSE SPECTRA
{
For defining seismic demand,-Wisconsin Electric will use the options provided }n the GIP, as appropriate, depending on the building, the location of equipment in the building, and the equipment characteristics.
The-licensing-basis Safe-Shutdown Earthquake (SSE) in-structure response spectra (ISRS) may be used
=
\\
l L
f.
-Document Control Desk September 21,-1992 Page 3 as one of the options provided in the GIP-for defining seismic demand.
For this option, the licensing bacis response spectra as described below will be used and are considered to be conservative design response spectra.
The in-structure response spectra curves for the design of equipment inside the buildings at Point Beach, are generated by the time history technique of seismic analysis.
The sample earthquake used is that recorded at Olympia, Washington, N80E, April 13, 1949 scaled to 0.0Cg (operating basis earthquake, OBE) peak horizontal ground acceleration.
The resultant in-structure response spectra are multiplied by a factor of 2 for seismic analysis with respect to the SSE.
Attachmant B provides a detailed explanation of the spectra development.
For the design of Seismic Class 1 structures at Point Beach, the input design ground motion is the Housner ground response spectrum scaled to 0.12g / hypothetical or safe shutdown earthquake, SSE) peak horizontal ground acceleration.
Section II.4.2.4 of the GIP states that " conservative design in-structure response spectra are defined as response spectra which have been computed roughly in accordance with the conservatism of current NRC Rogulatory Guidelines (such as Reg. Guide 1.61 for structural damping) and the Standard Review Plan (SRP). "
The GIP also states that "those plants which have been designed with Housner ground motion spectra-provide a suitable level df safety in the calculation of the resulting structural rerponse.
The adequacy of such existing design basis is net in question."
Figure B.1 shows that the scaled Olympia, Washington earthquake time history spectrum conservatively bounds the Housner ground response spectrum for frequencies >1.5 Hz.
At important structural frequencies between 2 Hz and 4 Hz,.the Olympia spectral amplitudes are nearly double the required Housner spectral amplitudes.
The Olympia, Washington earthquake time history is slightly lower than che
-Housner ground response spectrum for frequencies <1.5 Hz.
- However, there are no building natural frequencies below 1.5 Hz, tnerefore this has no affect on the seismic capacity of structures or equipment at Point Beach.
The Olympia, Washington earthquake time history spectrum and the Housner ground response spectrum are scaled to 0.01g peak horizontal acceleration for comparison purposes onlyo For determining seismic demand using the ground response spectrhm, the Housner ground response spectrum scaled to 3
0.12g SSE peak horizontal acceleration will.be used.
Based on the fact that the scaled Olympia earthquake time history spectra bounds the Housner ground-response spectra for frequencies
>1'.5 Hz, that s
the structural damping values are generally lower than those specified in Regulatory Guide 1.61 (see Table B.2), and that the Housner ground response spectra is not in question, Wisconsin Electric considers the in-structure response spectra, described in l
J
s Document Control Desk September 21, 1992 Page 4 Attachment D, to be " conservative design" spectra for use in the
-implementation of GIP to resolve USI A-46.
PLANT SEISMIC LICENSING BASIS Wisconsin Electric intends to change its licensing basis methodology for verifying the seismic adequacy of new and replacement electrical and mechanical equipment prior to receipt of a final plant-specific SER resolving USI A-46.
Wisconsin Electric will be installing two additional emergency diesel generators.
It is our intention to utilize the seismic. verification methodology provided in the SQUG GIP, where appropriate, for this project.
This licensing' basis change will be conducted under 10 C.F.R. 50.59 and will be consistent with the guidance in section 2.3.3 of Part I of the GIP, and with the clarifications, interpretations and exceptions identified in SSER-2 as clarified by the August 21, 1992, SQUG letter responding to SSIR-2 (Attachment A).
Any necessary changes to the FSAR will be provided in accordance with 10 C.F.R. 50.71(e;.
EClEPT Given the magnitude of the effort required to achieve resolution of USI A-46, final implementation nust be carefully integrated with the SQUG training schedules, plant outage schedules and the seismic
'IPEEE response.
The completion of the seismic IPEEE may be affected by the A-46 implementation' start'date.
Our plant-specific schedule for resolution of USI A-46 at Point Beach is included as follows:
ESTIMATED MILESTONE MILESTONE COMPLETION DATE SSEL/WALKDOWN AUGUST 1993 PREPARATION WALKDOWN PHASE NOVEMBER 1994 ANALYSIS and DOCUMENTATION PHASE MAY'1995 A-46/IPEEE
SUMMARY
JUNE 1995 REPORTS SUBMrrTAL TO NRC l
In accordance with Part II, Section 9 of the GIP, the A-46 Summary Report, consisting of a Relay Evaluation Report and a' Seismic
s i.
Document Control Desk September 21, 1992 Page 5 Evaluation Report, will rovide the results of the A-46 program implementation at Point Beach.
Our A-46 program completion schedule is dependent on our coordination with the seismic IPEEE activities, the availability and schedule for completing the necessary SQUG training, the availability of industry resources which may be limited because of the large number of licensees implementing this program, and the timing of NRC approval of the Point Beach in-structure response spectra submitted with this letter.
Since we are utilizing the available training orovided by SQUG and NUMARC and have already
[
contracted for assistance with the USI A-46/IPEEE project, we do not anticipate that these factors will cause any schedule delays.
We understand that, as stated in SSER-2 and clarified in the August 21, 1992, SQUG letter recponding to SSER-2 (Attachment A our in-structure response spectra are considered acceptable for USI A-46 unless the staff indicates otherwise during a 60-day review period.
If resolution of any NRC questions concerning the in-structure response spectra result in a change to the project schedule, we will notify you.
Sincerely,
'y-Q j
'j
/
Bob Link Vice President Nuclear Power Attachments cc:
NRC Resident Inspector NRC Regional Administrator Subscribepandswornto efore me this 4f21 day of J/, M g 1992.
A hl/ 1) $$A &
Notary Public, Std e of Wisconsin My Commission expires
/f//f/a.
TJD/hjo