ML18136A039

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Responds to 790928 Telcon Between Licensee,Nrc & S&W, W/Respect to Design of Piping Not Subjected to Computer Seismic Analysis.Results of Sample Problems Show Need for Mods to field-verified Piping Configuration
ML18136A039
Person / Time
Site: Surry Dominion icon.png
Issue date: 10/03/1979
From: Proffitt W
VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To: Harold Denton
Office of Nuclear Reactor Regulation
References
NUDOCS 7910100452
Download: ML18136A039 (2)


Text

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VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 October 3, 1979 W. L. PROFFITT SENIOR VICE PRESIDENT Mr. Harold R. Denton, Director Serial No. 802 Office of Nuclear Reactor Regulation PSE&C/CMRjr:mac:wang U.S. Nuclear Regulatory Commission Washington, DC 20555 Docket No. 50-280 License No. DPR-32

Dear Mr. Denton:

SEISMIC ANALYSIS OF PIPING SYSTEMS SURRY POWER STATION UNIT.1 During the telephone conference call between the NRC Division of Operating Reactors, Office of Inspection and Enforce~ent, both headquarters and Region II and Stone &Webster on September 28, 1979, the Division of Operating Reactors questioned information previously furnished by Vepco with respect to design of piping not subjected to computer seismic analysis. Since this information had been used in the Safety Evaluation Report with respect to the Order to Show Cause for Surry Unit 1, the Division asked if the information was incorrect and requested confirmation of the response in writing.

The material questioned is Item 2, Enclosure I, Attachment to Vepco Letter, Serial No. 220/040279 of May 24, 1979, to Mr. Victor Stello, Jr. As stated in the conference call, the information contained in Item 2 *is not incorrect. We have been informed by Stone &Webster that there has been no new information that would cause us to alter this statement in any way.

I As a result of a req~est by NRC Region II personnel in their letter of September 7, 1979, a total of five sample problems were reviewed. These five problems involved portions of the safety injection system and the reactor coolant system (RTD lines) and were originally analyzed using simplified methods as explained in our May 24, 1979 letter.

The results of the review show that as-built differences have been determined to exist. A comparison was made of the field verified piping system configuration against the presently available design documents. This comparison indicated that the following supports are not installed in accordance with the presently available design documents:

  • Problem Line No.

3000 System SI Designation 3"-SI-147-1503 Present Day Original RH moved around r~\iO o\

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v Q elbow and changed to strut. ~O~~tV 3003 SI 3"-SI-146-1503 Original RH moved around ~

elbow and changed to strut. \j 7910100 ~s-2-_

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e e VIRGINIA ELECTRIC AND POWER COMPANY TO , Mr. Harold R. Denton, Director 2 Problem Line No. System Designation Present Da,Y 3001 RTD 211 -RC-146-1502 (1) VC/LC missing 211 -RC-148-1502 (1) LC missing/(1) vc added 311 -RC-147-1502 ( 2) VC/LC missing (1) VC/AC added 3002 RTD 311 -RC-116-1502 (1) Anchor mssing (1) VC/LC missing 211 -RC-117-1502 (1) VC missing (1) VC/LC missing 3004 RTD 211 -RC-132-1502 (2) LC missing 311 -RC-131-1502 (1) Anchor missing (1) VC/LC missing AC = Axial Constraint VC = Vertical Constraint LC = Lateral Constraint RH = Rod Hanger These five sample problems have been evaluated by computer analysis using procedures approved for the Show Cause Order and the results indicate some modifications will be required. These modifications will be made before the unit is returned to service.

A more detailed description of the analysis of the five problems will be provided in our response to Mr. O'Reilly's letter of September 7, 1979.

If you should desire additional information, please contact us.

Very truly yours,_,----

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W. L. Proffitt cc: Mr. Victor Stello, Director Office of Inspection and Enforcement Mr. James P. O'Reilly, Director Office of Inspection and Enforcement Region II