ML16341E122
| ML16341E122 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 03/13/1987 |
| From: | Schierling H Office of Nuclear Reactor Regulation |
| To: | Shiffer J PACIFIC GAS & ELECTRIC CO. |
| References | |
| RTR-REGGD-01.084, RTR-REGGD-1.084 TAC-64501, TAC-64502, NUDOCS 8703200025 | |
| Download: ML16341E122 (16) | |
Text
March 13, 1987 Docket Nos.
50-275 and 50-323 Mr. J.
D. Shiffer, Vice President Nuclear Power Generation c/o Nuclear Power Generation, Licensing Pacific Gas and Electric Company 77 Beale Street, Room 1451 San Francisco, California 94106 DISTRIBUTION NRCPDR Local PDR PD83 RDg.
T. Novak OGC E. Jordan R. Ballard L. Chandler H.
Brammer M. Mendonca B. Grimes N. Thompson J. Partlow C.
Vogan H. Schierling ACRS(10)
D. Terao R.
Bosnak G. Bagchi P. Narbut
Dear Mr. Shiffer:
SUBJECT:
SNUBBER REDUCTION PROGRAM -
CODE CASE N-411 The staff is continuing its review of your snubber reduction program for the Diablo Canyon Nuclear Power Plant, Units 1 and 2, as described in your letters of February 15, 1984, May 16, 1984, January 21, 1986 and April 8, 1986.
Our letter of April 7, 1986 approved, with some restrictions, your request of January 21, 1986 to use Code Case N-411 in the program.
The restrictions identified in the letter and the conditions for acceptability of code cases in accordance with Regulatory Guide 1.84 are attached as Enclosures 1 and 2, respectively.
Our letter of March 13, 1987 approved the use of Branch'Technical Position MEB 3-1 for postulating pipe break locations as requested in your letter of April 8, 1986.
As part of our review of your proposed snubber reduction program the staff intends to conduct an audit of your implementation of Code Case N-411.
Enclosure 3 is a list of information needed and items we intend to address during the audit.
The list is intended to provide you with an indication of the scope of the audit and a written response to the items is not required at this time.
Additional information on related subjects may, of course, also be addressed during the audit.
~@DR ADOCK 05000275 Q3P0002g 8703 l3 t
Q ttf P It tl g
c'I i
'l tcfh tt] tt 7 1t '
>>'elf)
\\
l I (
nt n
t t4l'ltt'7
~ 7 7
i'i
~
I f
Ii I
l I ffl i
f r
It 7
if, l
flit it 7
If 7 F'l'll c 'ICl,"" ft lf 51,$
I I'
t tlfcl It 1~t) r)
1 fit
) lt i '7 tc fl 7 tf
We plan to conduct the audit in late March or early Apri1 at'your offices in San Francisco and at the Diablo Canyon Plant, as appropriate.
We request that you contact us as soon as possible so that an agreeable schedule can be arranged.
Sincerely,
Enclosures:
As stated Hans Schierling, Senior Project Manager Project Directorate-¹3 Division of PWR Licensing-A cc:
See next page PD¹3 CVogan*
3/12/87 PD¹3 HSch>
ing 3/g,/87 P
Sd ga 3/
/87
C%
\\
I
~I xf>
II, P
I ti k<,
h
~
f =II I
g ll t
C
)
1 8
f
~
t
Mr. J.
D. Shiffer Pacific Gas and Electric Company Diablo Canyon CC:
Richard F. Locke, Esq.
Pacific Gas 8 Electric Company Post Office Box 7442 San Francisco, California 941?0 Janice E. Kerr, Esq.
California Public Utilities Commission 350 McAllister Street San Francisco, California 94102 Ms. Sandra A. Silver 660 Granite Creek Road Santa Cruz, California 95065 Mr. W. C. Gangloff Westinghouse Electric Corporation P. 0.
Box 355 Pittsburgh, Pennsylvania 15230 Managing Editor San Luis Obispo County Telegram Tribune 1321 Johnson Avenue 1726 M Street, N.W.
Suite 1100 Washinoton'DC 20036-4502 Mr. Leland M. Gustafson, Manaqer Federal Relations Pacific Gas and Electric Company 1726 M Street, N.
W.
?0036-4502 Dian M. Grueneich, Esq.
Edwin F. Lorry, Esq.
Grueneich 8 Lowry 345 Franklin Street San Francisco, California 94102 NRC Resident Inspector Diablo Canyon Nuclear Power Plant c/o U.S. Nuclear Regulatory Commission P. 0.
Box 369 Avila Beach, California 93424 Mr. Dick Blakenburg Editor 8 Co-Publisher South County Publishing Company P. 0.
Box 460 Arroyo Grande, California 934?0 Bruce Norton, Esq.
c/o Richard F. Locke, Esq.
Pacific Gas and Electric Company Post Office Box 7442 San Francisco, California 94120 Dr.
R.
B. Ferguson Siera Club - Santa Lucia Chapter Rocky Canyon Star Route Creston, California 9343?
Chairman San Luis Obispo County Board of Supervisors Room 220 County Courthouse Annex San Luis Obispo, California 93401 Director Energy Facilities Siting Division Energy Resources Conservation and Development Commission 1516 9th Street Sacramento, California 95814 Ms. Jacquelyn Wheeler
?455 Leona Street San Luis Obispo, California 93400
Pacific Gas A Electric Company 2 -
Diablo Canyon CC:
Ms. Laurie McDermott, Coordinator Consumers Organized for Defense of Environmental Safety 731 Pacific Street, Suite 42 San Luis Obispo, California 93401 Mr. Joseph
- 0. Ward, Chief Radiological Health Branch State Department of Health Services 714 P Street, Office Building 88 Sacramento, California 95814 Ms. Nancy Culver 192 Luneta Street San Luis Obispo, California 93401 President California Public Utilities Commission California State Building 350 McAllister Street San Francisco, California 94102 Regional Administrator, Region V
U.S. Nuclear Regulatory Commission 1450 Maria Lane Suite 210 Walnut Creek, California 94596
4
ENCLOSURE 1
CRITERIA FOR USE OF ASNE CODE CASE N-411 FOR DI AND 2 Use o~ Code Case N-411 is limited to only those cases where the response spectrum method of seismic analysis
'is applied along with the modal superposition technique.
The FSAR and other applicable documents must be amended to identify the licensee's request for the application of Code Case N-411 and the staff's approval of the request.
The application of Code Case N-411 shall be included in the FSAR to maintain in the licensee's engineering records a
current list and individual files of all pipe stress packages reanalyzed using Code Case N-411.
All revised pipinq stress analyses packaaes must be identified as calcul-ations of record, and are, therefore, subject to applicable requirements of 10 CFR Part 50 Appendix B.
Mhere predicted maximum piping displacements usina Code Case N-411 criteria exceed the current design calculations by an amount greater than acceptable tolerance levels, a physical verification of the availability of adequate clearance with adjacent structures, eouipment and components must be performed.
For equipment mounted on piping such as valves with extended structures, proper account must be taken for both rotation and translation in arriving at the predicted maximum displacement at the extreme ends of pipe mounted equipment.
It must be verified that the operability qualification level of pipe mounted equipment is not exceeded by the predicted response using Code Case N-411.
Mhere the existing design loads of piping supports are exceeded by the new loads predicted by the use of Code Case N-411, it must be verified that the new loads do not exceed the design capacity of the supports.
Jt must be verified that the cumulative effect of the changes of loads on piping supports that are in turn supported by a structural element of a building, such as walls, slabs, beams and columns, does not exceed the load carrying capacity of the affected structural element.
The use of Code Case N-411 damping values is restricted to piping sections only.
Code Case N-411 damping values must not be mixed with the values in Regulatory Guide 1.61.
This is especiall.y important to note since the Requlatory Guide 1.61 damping values could be higher for some modes (higher frequency modes} compared to the values permitted by Code Case N-411.
Also Code Case N-411 damping values are not applicable to equipment and components either attached to or mounted on the pipe.
For a piping run with equipment and components the composite damping approach is acceptable.
In the composite damping approach energy dissipation in piping sections should be consistent with Regulatory Guide 1.61 damping values.
ENCLOSURE 2
CONDITIONS IMPOSED BY REGULATORY GUIDE 1.84 ON USE OF ASME CODE CASE N-411 1.
The damping values specified may be used in analyzing piping response for seismic and other dynamic loads being filtered through building structures, provided response mode frequencies are limited to 33 Hz and below.
2.
Within the frequency range, 0 to 33 Hz, the Code Case damping should be used completelv and consistentlv, if used at all.
3.
For equipment other than piping, the damping values specified in
~
Reaulatory Guide 1.61 should be used.
4.
The damping values specified may be used only in those analyses in which current seismic spectra and procedures have been employed.
Such use should be limited only to response spectra analyses (similar to that used in the study supporting its acceptance
- Reference NUREG/CR-3526).
The acceptance of the use with other types of dynamic analyses (e.g.,
time-history analysis) is pending further justification.
5.
When used for reconciliation work or for support optimization of existing
- designs, the effects of increased motion on existing clearances and on line mounted equipment should be checked.
6.
The Code Case is not appropriate for analyzing the dynamic response of piping systems using supports designed to dissipate energy by yielding.
7.
The Code Case is not applicable to piping in which stress corrosion cracking has occurred unless a case specific evaluation is made and is reviewed by the NRC staff.
\\
~ h
ENCLOSURE 3 SNUBBER REDUCTION PROGRAM FOR DIABLO CAN UNITS I AND 2 B
NF.
FF U
I.
PROGRAM 2.
Discuss your proposed revision to the Diablo Canyon Units 1 and 2
FSAR Update relating to the snubber reduction program.
In your letter of January 21, 1986 you indicated that NRC reactions to recent developments in snubber reduction methodology would be monitored and that additional methods would be considered for addition to your program.
Identify any additional methods being considered in your snubber reduction program.
3.
Provide documentation to demonstrate that your snubber reduction program is in conformance with the requirements in 10 CFR 50 Appendix B.
Demonstrate that your snubber reduction program will be limited to cases where the response spectrum method of analysis was utilized alona with the modal superposition technique.
5.
6.
7.
8.
9 10.
Explain how the provision of Code Case N-411 will be used completely and consistently in your program.
Demonstrate that your snubber reduction program is not being applied to piping systems in which stress corrosion cracking has occurred or is likely to occur.
Demonstrate that your snubber reduction program will not be applicable to lines containing energy absorbing supports.
Explain what effect the reanalysis has on the impact on break locations for dynamics effects associated with postulated rupture of piping.
In your letter of January 21, 1986 you indicated that the first step in your program is the formation of a comprehensive data base of snubber location information.
Provide an overview of your data base.
Information regarding the number of snubbers used for each piping analysis, related radiation levels and buildinq areas and elevations transversed by the pipe in the analyses should be available for review.
Explain your commitment in your letter of January 21, 1986 to maintain in the enqineering records a current list and individual files of all pipe stress packages reanalyzed using Code Case N-411.
Additionally, the,relationship between your commitment and the requirements of ASME Code Section XI relating to modifications to existing plants should be explained.
Il.
Demonstrate that response mode frequencies will be limited to 33 Hz and below for the earthquake, double design earthquake, and Hosgri earthquake.
12.
Detail the number of piping systems being reanalyzed and the safety classes involved in the reanalysis.
13.
Explain the status of the reanalysis and walkdowns for your program.
14.
Demonstrate that damping values for equipment are in accordance with Regulatory Guide I.61.
35.
Explain the status of the analyses required to requalify safety-related equipment in your program.
II PROCEDURES 1.
Fxplain your procedures used to obtain the response spectrum for the lines to be reanalyzed.
2.
Explain the procedures used to identify those snubhers which were considered for replacement by rigid struts.
3.
Explain any'changes in the thermal operating conditions or temperatures used in the reanalysis.
4.
If a "special support optimization computer program" was used, provide information during the audit to establish the accuracy of such a program.
Explain any changes in the methods or criteria used to obtain or evaluate nozzle loads, supports
- loads, pipe stresses, and clearances.
Identify any locations where these methods or criteria were not applied consistently.
6.
Identify any proposed modifications to building attachments that resulted from the reanalysis.
III.
IMPLEMENTATION 1.
Provide documentation during the audit to verify that the procedures have been implemented properly on one or more lines.
These lines wil1 be identified during the audit.
'I I
r 4