ML20246J158

Rev 0 to Safety Sys Outage Mod Insp,Nrc Finding MC-1

ML20246J158
Person / Time
Site:	North Anna
Issue date:	08/09/1989
From:	Bhargava V, Sorrell C VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:
Shared Package
ML20246J098	List: ML20246J091 ML20246J099 ML20246J107 ML20246J119 ML20246J126 ML20246J139 ML20246J148 ML20246J158
References
CE-0017, CE-0017-R00, CE-17, CE-17-R, NUDOCS 8909050049
Download: ML20246J158 (7)

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, -TECHNICAL REPORT NO. CE-0017 REY. 0 SAFETY SYSTEM OUTAGE MODIFICATION INSPECTION NRC FINDING MC-1 NORTH ANNA POWER STATION, UNIT 2 r

CIVIL ENGINEERING POWER ENGINEERING SERVICES VIRGINIA POWER AUGUST 7, 1989 M NN-Prepared by: N# I. D.

V. M. Bhargava 9 Date Reviewed by: (niltd k) Mel tto 9719-(. N. Mehrotra - -

Date

. Approved by: e jrkt1

/- 9-#9 C. E. Sorrell Date QA CATEGORY: SAFETY RELATED Key Words:

SSOMI NUCLEAR REGULATORY COMISSION FINDING MC-1 1

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TABLE OF CONTENTS TITLE PAGE COVER PAGES 1 TABLE OF CONTENTS 2

1.0 INTRODUCTION

3 2.0 SCOPE 3 3.0 METHODOLOGY 3 4.0 VERIFICATION AND RESULTS 3-6

5.0 CONCLUSION

S 6

6.0 REFERENCES

6 7.0 ATTACHMENTS- 6, 7 103-VMB-7249S-2

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1.0 INTRODUCTION

In February-March,11989, NRC conducted design portion of the Safety System-Out' age Modification Inspection (SSOMI) for North Anna Power Station Unit 2.

One'of the purposes of-the' design portion of the SS0MI was..to examine the detailed design and engineering that were required to support modifications implemented during.the outage. SS0MI was for reviewing planned ~ plant changes:and for ascertaining if the as-modified. plant remained in accordance with its licensing basis.

NRC SS0MI team identified the following "significant" item:

"A change was made to~ a pipe support baseplate to enlarge the holes, without proper design justification. (See Appendix C Finding MC-1)."

A copy of the NRC' report is attached. See Attachment 1.

2.0 SCOPE The scope of this . report is to document the review of 10 randomly sampled pipe support field. change requests as desired by NRC.in their finding MC-1.

NRC wants VEPC0 "to ensure similar problems with design verification are not pervasive." This report also explains the changes that are

. contemplated to ensure that an adequate design verification is performed for future modification.

Mr. C. A. Zalesiak reviewed NRC finding MC-1. His comments are appended.

See Attachment 2.

3.0 METHODOLOGY As directed by the NRC,10 pipe support field change requests were randomly selected. See Attachment 3. These change requests were individually

' investigated. The resulting findings are documented as follows:

4.0 VERIFICATION AND RESULTS:

4.1 Design Change No. 84-71-1, Revision No. 61:

Paragraph 2.1 of the field change provides adequate engineering l- justification for the change. An examination of SWEC calculation no.

14938.02-NM(B)-451-JC and applicable design drawing no. N8471-1-1FV69A confirmed the adequacy of the justification. See Attachment 4.

4.1.1 Design justification is determined to be' adequate.

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4.2 Design Change No. 84-71-1, Revision No. 68:

An engineering evaluation was performed at the time of dispositioning the field change. The baseplate of the revised design is installed.

However, no structure is attached to it. This design change has not been fully implemented. The calculation covering this FC is in progress and will be completed by the time the design change is closed out. See Attachments 5, 6 and 7.

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' Design justification;is determined-to.be adequate. 1

h. ' '4;3..- Design Change No. 87-13-1, Revision No.13i lY' 'With the. help of this FC, (8) pipe supports were added. The, lines are' non-safety and non-seismic:and are small bore (2" dia- ) . lines. .The .

pipe' support locations were designed by keeping in mind the.

requirement: of ANSI. B31.1 code. The pipe supports were designed according to NAS-1009.

4.3.1 R'esul t -

i . Design justification is determined to be adequate.

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4.4 ; Design Change No.-88-12-2, Revision No. 36:' -

• This fiel'd change deals with (4) changes. The first change. pertains-to '" damaged threads on the end of:the bolt outside' the nut." The evaluation of' this modification is adequately described in the field--

change.

The second.cha'nge relates to-two maximum dimensions.that were exceeded.

by 1" or less. This 'ondition c was analyzed by SWEC in their.

calculation no. 14938.50-NZ(B)-002-ZB,.page 17. See Attachment 9.

The. analysis demonstrated that the change was' acceptable.

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The third change pertained to a tighter clearance in the ~ lateral ,

direction between the pipe and' the restraining strap. Because the pipe is cold (design temperature = 150 F),' lack of clearance does not affect the pipe support. There would be no thermal loads and no consequential . frictional forces to contend with.- The changed design

<is therefore, acceptable.

The fourth change involved rotating member no. 3 in order to accommodate the pipe slope. This was. accomplished by interposing a-plate between the two member no. 3. Because members are closed sections and interposed with a 1" thick plate that has been fillet welded all around, the change is acceptable.

4.4.1 Result Design justification is determined to be adequate.

} 4.5 Design Change No. 88-12-2, Revision No. 18:

Evaluation of this change is documented in SWEC calculation no.

14938.50-NZ(B)-002-ZB page 2.10. See Attachment 9.

4.5.1 Result Design justification is determined to be adequate.

4.'6 ' Design Change No. 88-11-1, Revision No. 25:

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1 This' change'in the structure is documented in SWEC calculation no.

[, 14938.50-NZ(B);-004-ZB-010. .See Attachment 10.

s p 4.6.1 Result Design justification is determined to be adequate.

-4.7 Design Change.No. 88-11-1,. Revision No. 21:

This FC' involved (3) changes. The first change related to the-baseplate, which got distorted as a result of excessive heat of L welding' during installation. The baseplate " lifted up" around its l periphery outside the bolt pattern. Discussions with SWEC representative, Mr. Gary E.. Modze'lewski, confirmed that there were no gaps between the back of the baseplate and the wall. Just to improve the aesthetics of the pipe. support, shims were added along the top and bottom edges of'the-baseplate.

' The second change had to do with using Hilti Kwik bolts of a bigaer size than what had been specified. It was confirmed with SWEC.

representative that there were no other concrete fasteners near these bolts resulting in a reduction of the load carrying capacity of ,these bolts. Therefore, substituting the bigger bolts netted a higher load carrying capacity for the pipe support. This situation is acceptable.

The last change involved attaching a support no. H-28 to'an existing restraint baseplate. The pipe support design is based on a generic SWEC standard. A review of their calculation no. 14938.50-NZB-004-

'ZB-003-(Attachment No.13) confirmed the validity of the pipe support-design. The attachment of the pipe support to pipe rupture restraint 1-RC-PRR-34 is documented in SWEC calculation no. 14938.50-S-4. See Attachment no. 11, 4.7.1 Result Design justification is determined to be adequate.

4.8 Design Change No. 85-11-1; Revision No. 6:

This change pertained to (2) Hilti Kwik bolts out of a total of (4) specified. The change: the final embedment was 31" as compared to 4" specified in the drawing.

SWEC calculation 14938.62-NZ(B)-003-ZB documents the use of Hilti Kwik Bolts with 31". See Attachment 12.

4.8.1 Result Design justification is determined to be adequate.

4.9 Drsign Change No. 89-01-3; Revision No. 1:

Tnis change was concerned with using certain baseplates having over sized holes for anchor bolts. In order to conserve time and material, washers with the correct size holes were welded on top of the 103-VMB-7249S-5

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baseplate, at the location of oversize holes in the baseplate. The l engineering justification is recorded in the calculation CE-0629 R/0, j sub calc. no 15.- -

4.9.1 Result Design justification is determined to be adequate.

4.10 Design Change No. 86-02-1; Revision No. 6:

The change and its engineering evaluation are well described in the FC.

4.10.1 Result Design justification is determined to be adequate.

5.0 CONCLUSION

S As documented in this report, a review of the 10 randomly selected field changes was conducted. The design justification,.in some cases, was described in the body of the field change. In the remaining cases, the evaluations were either recorded in the calculations or could be reasoned out with a little effort. In all of the cases, the adequacy of the design justification was determined to be acceptable.

It is also concluded that in all the cases examined, the as-modified plant remained in accordance with its licensing basis.

However, in order to enhance the system, NDCM procedure no. 3.7, titled

" Calculations," shnuld be revised. It should not be adequate to just state "0K BY ENGINEERING JUDGMENT" or any such words. The revised procedure should ask for documenting the rationale .behind any engineering judgment calls. There should be a clear documented traceability of the justification for " buy-offs" of field changes.

6.0 REFERENCES

Nuclear Design Control Manual Procedure NDCM 3.11 Rev. 2 - Technical l

Reports.

7.0 ATTACHMENTS

1. NRC letter of 6/29/89 to Mr. W. R. Cartwright.

2. Mr. C. A. Zalesiak comments on NRC discussion of EWR 87-671.

Memorandum from Mr. J. E. Wroniewicz to Mr. C. E. Sorrell dated July 3.

13, 1989.

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! 4. Drawing no. N8471-1-1FV69A Rev. 9.

l SWEC Calculation 14938.02-NM(B)-451-JC

5. Memorandum from Mr. V. M. Bhargava to Mr. Bob Bain dated July 31, 1989.

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'6... Drawing no. 'N8471-1-M-64' Rev.1.

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8. SWEC: calculation'.no.114938 02-NP(B)-001-ZB Rev. 1,. Change: letter.A.o

9. SWEC calculation' no. 14938.50-NZ(B)-002-ZB_Rev.-0,Changeletter'A.

10. SWEC calculation no. 14938.50-NZ(B)-004-ZB-010 Rev. O~ .

11.'..SWEC. calculation no. 14938.50-S-4 Rev. 0

12. SWEC' calculation no. 14938.62-NZ(B)-003-ZB'Rev.O.

13. SWEC calculation no. 14938-NZB-004-ZB-003

~14. Memorandum from Mr.. V.. M. Bhargava to.Mr. Gary E. Madzelewski dated

. August 8, 1989.

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