ML19256G413

Responds to IE Bulletin 79-02,Revision 2, Pipe Support Base Plate Designs Using Concrete Expansion Anchor Bolts. No Pipe Supports for Seismic Category 1 Sys Attached to Concrete Block Walls W/Anchor Bolts at Facilities

ML19256G413
Person / Time
Site:	North Anna
Issue date:	12/07/1979
From:	Brown S VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
IEB-79-02, IEB-79-2, IEB-79-2-R2, NUDOCS 7912310255
Download: ML19256G413 (3)

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VIRGINI A ELECTRIC *AND POW ER COMP ANY, RICHMON D, VIRGINI A 23261 f 10eceder @S 1979 Mr. James P. O'Reilly, Director Serial No. 943/110879 Office of Inspection & Enforcement PSE&C/CES:VML: wang U. S. Nuclear Regulatory Commission Region II Docket Nos. 50-338 101 Marietta Street, Suite 3100 50-339 Atlanta, Georgia 30303 50-404 Su-405

Dear Mr. O'Reilly:

License No. NPF-4 I.E. Bulletin No. 79-02 addresses " Pipe Support Base Plate Designs Using Concrete Expansion Anchor Bolts." Our previous responses to this bulletin and its subsequent Revision 1 are listed below for your reference:

Letter Serial No. Date Identification 402 May 24,1979 North Anna Unit 2 Response to I.E.

Bulletin No. 79-02 402A June 29, 1979 North Anna Unit 3 and 4 Response to I.E. Bulletin No. 79-02, Revision No. 1

, 402B July 6, 1979 North Anna Unit 2 Response to I.E.

Bulletin Na. 79-02, Revision No. 1 545 July 6, 1979 North Anna Unit 1 Response to I.E.

Bulletin No. 79-02, Revision No. 1 This letter provides the additional information requested by I.E. Bulletin 79-02, Revision No. 2 dated November 8, 1979 for North Anna Units 1 through 4.

Item 5 of the revised bulletir, requires determination of the extent that expansion anchor bolts were used in concrete block (masonry) walls to attach piping supports in Seismic Category I systems. If it is determined that expansion anchor bolts were used in concrete block walls, completion of items Sa. through 5d. is required.

Fer North Anna Units 1 and 2, a recent inspection of block walls located in Seismic Category I structures verified that there are no pipe supports for Seismic Category I systems attached to concrete block walls with expansion anchor bolts.

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As stated in our letter Serial No. 402A dated June 27, 1979, no Seismic Category I pipe support base nlates have been installed to date on North Anna Units 3 & 4. The present design methods will attempt to minimize the use of concrete expansion anchor bolts for pipe support base plates in Seismic Category I systems by providing cast-in-place embedded base plates and Richmond inserts for anchorage. Simil:rly North Anna Units 3 and 4 do not intend to use concrete expansion anchors in masonry block walls to support Seismic Category I piping systems.

Item 6 of the revised bulletin requires determination of the extent that pipe supports with expansion anchor bolts used structural steel shapes instead of base plates. Upon review of the systems consistent with the criteria of I.E. Bulletin No. 79-02, Revision 1, if it is determined that expansion anchor bolts were used as described above, verification is required that the anchor bolt and structural steel shapes in these supports were included in the actions performed for the bulletin.

In response to iten 6 for North Anna Units 1 and 2, all pipe supports attached to concrete using expansion anchor bolts are consistent with the criteria of I.E. Bulletin No. 79-02. As addressed in our letters, Serial No.

402 dated May 24, 1979, Serial No. 402B dated July 6, 1979, and Serial No. 545 dated July 6,1979, all Seismic Category I concrete founded pipe supports were checked for flexibility and all concrete expansion anchor bolts on these supports were QC inspected and documented under the anchor bolt inspection program instituted in 1977. This review and inspection included any supports using structural steel shapes instead of base plates. All supports added or modified since this inspection were designed using guidelines to assure rigidity and were under expanded construction and quality control procedures which used a sampling system for verification.

For North Anna Units 3 and 4, embedded plates or Richmond inserts will generally be used for support of Seismic Category I piping systems. However,

- if structural steel shapes are used instead of base plates, then the review of the structural steel shapes will be performed consistent with the criteria of I.E. Bulletin No. 79-02, Revision 2.

The responses to the remaining items of the revised bulletin as addressed for North Anna Units 1 through 4 are as stated in our previous letters listed in the first paragraph of this report.

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In sunnary, the procedures herein discussed for North Anna Units 1 through 4 ensure that the design and installation of expansion anchor bolts have been (in the case of Units 1 and 2) or will be (in the case cf Units 3 and 4) performed in a manner which satifies the requirements of I.E. Bulletin 79-02, Revision 2.

Very tru yours, Sam C Br n, Jr.

Senior Vice Presi nt - Power Station Engineering and Construction cc: Mr. Victor Stello, Director Office of Inspection & Enforcement Mr. Harold R. Denton, Directer Office of Nuclear Reactor Regulation i658 052

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