ML20237L161

Requests Clarification of SER Re SEP Topic III-6, Seismic Design Considerations. Clarifications Concern Technical Criteria Stated in DC-1,Rev 4 (Ref (E)) & Could Impact Scope of Mods.Util Understandings of Mutual Agreements Encl

ML20237L161
Person / Time
Site:	Yankee Rowe
Issue date:	08/31/1987
From:	Papanic G YANKEE ATOMIC ELECTRIC CO.
To:	Fairtile M NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM), Office of Nuclear Reactor Regulation
References
TASK-03-06, TASK-3-6, TASK-RR FYR-87-91, TAC-51807, NUDOCS 8709080246
Download: ML20237L161 (7)

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• Telephone (617) 872-8100 TWX 710-380 7619 YANKEE ATOMIC ELECTRIC COMPANY q 1671 Worcester Road, Framingham, Massachusetts 01701 J

August 31, 1987 FYR 87-91 i United States Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 Attention: Mr. Morton Fairtile, Project Manager Project Directorate I-3 Division of Reactor Projects I-II

References:

(a) License No. DPR-3 (Docket No. 50-29)

(b) Letter. YAEC to USNRC, dated June 1, 1987, SEP Topic III-6, Commitment Summary (c) Letter, USNRC to YAEC, dated July 16, 1987, NUREG-0825, Section 4.11. Seismic Design Considerations (TAC No. 51807)

(d) Letter,'YAEC to USNRC, dated July 13, 1987, SEP Commitments (e) Document No. DC-1, Revision 4, submitted via Letter, YAEC to USNRC, dated April 30, 1987 (f) Letter, UShTC to YAEC, dated February 10, 1983, SEP Topic III-6, Seismic Design Considerations, Yankee Nuclear Power Station

Subject:

Clarification of Staff Position, SEP Topic III-6, Safety Evaluation Report

Dear Sir:

We have reviewed the Safety Evaluation Report for SEP Topic III-6, Seismic Design Considerations, for the Yankee Nuclear Power Station (YNPS)

.(Reference (c)). Clarification of the staff position is requested for the items listed in Attachment 1. For a number of these items, the staff position appears to be in conflict with the agreements reached between Yankee Atomic Electric Company (YAEC) and the staff during the SEP Topic III-6 meetings which occurred over the past 18 months. Our understandings of the mutual agreements are also listed in Attachment 1.

Many of these clarifications concern technical criteria stated in DC-1, Revision 4 (Reference (e)). This document, which was originally prepared in 1980, has been subjected to extensive review and revision over the past 18 months at the specific direction of the staff and your consultants.

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United States Nuclear Regulatory Commission August 31, 1987 Attention: Mr. Morton Fairtile, Project Manager Page 2 FYR 87-91 1'

l The disposition of'these issues could potentially impact the. scope of  ;

modifications and, therefore, affect the schedule for. implementation of the commitments made by YAEC for SEP Topic III-6. We, therefore, request clarification of your position on these issues as expeditiously as possible since work cannot be started until these issues are resolved.

Very truly yours, YANKEE ATOMIC ELECTRIC COMPANY G. Pa nic, Jr.

Senior Project Engineer - Licensing DL/1.148 Attachment cc: USNRC Region I USNRC Resident Inspector, YNPS

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l. ATTACHMENT 1 I I

Attachment to Letter FYR 87-9',

SEP Topic III-6, Safety Evaluation Report

1. Page 10 Section 4.3.4(1): " Verification of grouting in masonry walls where anchor bolts and strap anchors were installed."

YAEC Understanding: In Item 12 of Reference (b), YAEC committed to verifying only that strap anchors in the Primary Auxiliary Building north wall were solidly grouted. YAEC did not commit to verifying the grouting of anchor bolts. Further, no mention of anchor bolts is found in Item 12 of Section 5.2 of the SER or in Attachment 5 to the SER.

Currently, the only grouted anchor bolts present in masonry walls are those added during recent modifications. Documentation of the grouting of these anchor bolts exists.

2. Page 16, Section 4.3.13: "YAEC has committed to perform the analysis (Main Steam /Feedwater) in 1987 and to implement any needed modifications in 1988."

YAEC Understanding: The resolution program for all YAEC commitments resulting from all SEP topics is currently being scheduled. The above dates were based on receiving the SEP Topic III-6 SER in 1986, rather than July of 1987. The schedule will be submitted to the staff upon its completion.

3. Page 16, Section 4.3.13: "To this end, YAEC committed (Reference 41) to submit the analysis report [for Main Steam /Feedwater) for staff's review when completed."

YAEC Understanding: In Reference (d), which is Reference 41 of the SER, YAEC committed to advise the NRC Project Manager upon completion of SEP commitments. Engineers and calculations would be made available to the staff at that time. YAEC did not commit to preparing and submitting an analysis report for the Main Steam /Feedwater seismic upgrade. j

4. Page 21, Section 4.4.1.1: "In some cases, YAEC performed the second  !

combination using 60% of the Seismic Anchor Motion (SAM) loading. This was not acceptable to the staff based on the findings of the example analyses discussed in Attachment 3, and YAEC has agreed to revise all affected calculations to remove the use of the 60% SAM loading."

Attachment 3. Page 14, Section 2.2.3: "The reduction of SAM to 60% when combining with thermal loads in either a YCS analysis or an NRC spectrum analysis is not acceptable using PVRC damping "

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ATTACHMENT 1-(l (Continued)

Attachment 3 -Page 27, Section 3.2.7(2.3): "A reduction of SAM loads to I L

60% was not applied in combining SAM loads with other loads. In Reference 27, the licensee agreed to modify affected existing calculations.to remove use of this methodology. This issue is discussed E in detail under Question D27 in Appendix A."

YAEC Understanding: In Reference (b), which is Reference 27 above, YAEC l agreed to use 100% of the SAMs in combination with thermal loads.in ANSI B31.1. Equations 13 and 14, for YCS analysis only. YAEC did not agree to use 100% SAM in combination with thermal loads for NRC spectrum analysis.

As shown below, DC-1, Revision 4, Section 8.3.1(c) (Reference (e))

clearly states that 60% SAM may be used in combination with the thermal loads:

For the NRC load case, since Equation 8.3.1-C is a Level A/B stress comparison, and since the NRC Spectra represent much greater load cases than an OBE, 60% of the SAM effects will be used in M c.

This 60% is intended to limit the SAM results to the same levels as an OBE code analysis would. However, if the 60% SAM combination is used at any point, the strain criteria shall not be used at the same point.

Although there is a restriction on the use of strain criteria and 60%

SAM, there is no restriction on the use of PVRC damping together with 60%

SAM.

DC-1, Revision 4, was reviewed and approved by the staff and your consultant prior to formal submittal. In fact, at the direct request of the staff's consultant, a restriction was placed on the use of strain criteria when the 60% SAM reduction is used.

It should also be noted that the use of 60% SAM, when combined with thermal loads, was also present in DC-1, Revision 2. The staff reviewed and approved this document in 1983 in Reference (f).

On this same issue, further clarification is in order regarding the TER (Attachment 3 to the SER). In Section 4.29.ii of Appendix A of the TER, it is stated that YAEC proposed to combine 60% SAM with seismic inertia in ANSI B31.1, Equation 12. YAEC did not propose this combination. YAEC did propose using the SRSS combination of seismic inertia and 100% SAM in Equation 12.

In Section 4.29.1 of Appendix A to the TER, a rationa3e is provided for I not accepting the use of 60% SAM in ANSI B31.1, Equations 13 and 14, with YCS analysis. YAEC has agreed to this. However, this rationale does not I hold for NRC spectrum analysis, since the NRC spectrum is an upper level SSE.

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• T- (Continued) c;; Loads-due'to the NRC spectrum are Level D.(faulted). loads.' In the 1983 ASME Boiler and Pressure Vessel-Code,Section III, for Level D loadings, Q2 loads from' SAM are. required in Equations 9, 10, or 11 (the equiv3!ent of; ANSI B31.1, Equations 12, 13, and 14, respectively).

. :Furthermore, the' allowable stress for. Level D in the code is higher than that allowed by our DC-1,. Revision 4. Also, NUREG-1061. recommends the use of 0BE SAMs-(50% of SSE SAMs) when combining SAMs with thermal loads.

l

.. n Based:on the above discussion, it can be seen that the use of 60% of SAMs

]T .due'to NRC spectrum loads when combining SAM loads with thermal loads is

• i co'nservative.

i, t Additionally, for those piping analyses using NRC spectrum loads, YAEC has. consistently applied this analytical methodology since it was first

. approved by the staff prior to 1983.

5. Page 21, Section 4.4.1.1: "YAEC has agreed to perform this check

[ doubling YCS loads] and committed to use NRC spectrum' analysis for all

. future major evaluation and modifications of piping."

YAEC Understanding: In Item 19 of Reference (b), YAEC committed to use NRC spectrum analysis for major modifications to existing and new SSS piping. YAEC did not commit to using only NRC spectrum analysis for major evaluations of piping.

YAEC has agreed that any piping qualified using YCS analysis would be checked as described in Item 18 of Reference (b).

6. Page 23 Section~4.4.1.3: "A limited application of SRSS combination of seismic inertia and anchor motion loads was proposed for NRC spectrum

-loading. Based on the SONGS 1 SERs, this was found acceptable with the understanding that-all such applications be reviewed and approved by the staff."

Attachment 3. Appendix A, Page A-37, Section 5.4.3: "The proposal to use this combination (SRSS of SAM and SI) with NRC spectra was retained and remained acceptable to the NRC staff, provided that all such applications l be subjected to a case-by-case review by the staff. The DC-1 criteria document has been revised to incorporate this change and reviewed and approved by the staff. CLOSED."

' YAEC Understanding: As stated in Section 9 of DC-1, Revision 4 c'

[ Reference (e)], no restrictions are placed on the use of the SRSS combination of SAM and seismic inertia loads on pipe supports when using NRC' spectrum analysis.

The SER seems to be contradictory. Page 23, Section 4.4.1.3, and Page'A-37, Section 5.4.3 require case-by-case review and approval.

However, Page 24, Section 4.4.1.3, and Pages 21 and 22 of Attachment 3 place no such restrictions on this combination. Furthermore, DC-1, Revision 4, has been reviewed and approved by the staff and your consultants prior to the preparation of your SER.

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l ATTACHMENT 1 1 (Continued)

L 7. Page'23, Section 4.4.1.3 and Attachment 3, Page 20, Section 2.3.2:

l3 "(Small Bore Pipe Supports) If the support deflection was less than 1/8" f for the total loading, and less than 1/16" for the seismic loading alone, the support was considered acceptable." l YAEC Understanding: The criteria, as clearly stated in DC-1, Revision 4, i Section 9.5, is as follows: 1 1

For supports checked to the deflection criteria, support structure deflections due to the total design' load at the point of restraint are acceptable if less than 1/16". Deflections greater than 1/16" are  !

acceptable only if the total displacement is less than 1/8" for the design loading, but less than 1/16" for primary loading.

8. Page 32. Section 5.2: " Implementation will be conducted in stages over the next three years (two refueling outages)."

YAEC Understanding: The resolution program for all YAEC commitments resulting from all SEP topics is currently being scheduled. This will be submitted to the staff upon its completion.

10. Attachment 3. Appendix A, Page A-28, Section 4.31.5.2: "The SUPERPIPE code has an automatic masspoint ...."

YAEC Understanding: SUPERPIPE appears to be a typographical error. The correct code is ADLPIPE.

11. Attachment 3, Appendix A, Page A-42, Section 6.1.6: "Although the licensee withdrew the general proposal to use Hilti HVA (resin) concrete anchors ...."

YAEC Understanding: YAEC withdrew the proposal to use Hilti HVA anchors in masonry only. YAEC reserves the option to use these anchors for applications other than in masonry.

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