ML19338D222

Submits Addl Info Re IE Bulletin 79-14, Seismic Analysis for As-Built Safety-Related Piping Sys. Stress Calculation on Main Steam Line Outside Containment Was Calculated Using Proposed Mod Support Sys Instead of as-built Configuration

ML19338D222
Person / Time
Site:	Davis Besse
Issue date:	08/18/1980
From:	Crouse R TOLEDO EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
1-158, IEB-79-14, NUDOCS 8009220176
Download: ML19338D222 (2)

Text

N ('

di 10teoo E EDISON Docket No. 50-346 n.mue o cm a License No. NPF-3 CJf7"" '

ws o.w Serial No. 1-158 August 18, 1980 <

Mr. James G. Keppler Regional Director, Region III office of Inspection and Enforcement U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137

Dear Mr. Keppler:

In our June 16, 1980 letter (Serial No. 1-137) we reported the completion of the follow-on analysis of identified discrepancies for normally accessible safety related piping required by IE Bulletin 79-14 The results of this follow-on analysis supported our preliminary evaluation that the operability a of safety related systems was unaffected.

Subsequent to our letter, further review of the completed analysis for one stress calculation on the main steam line outside of containment (stress calculation 10A) revealed that the pipe support loads had been calculated

, utilizing a proposed modification support system instead of using the as-

built configuration. This propc cd pipe support was intended to be added to reduce the piping stress levels to below the long term acceptance levels.

Without this additional pipe support the stress level in the piping was still below our interim or short term acceptance levels. However, when the pipe support loads were recalculated using the current, as-built configuration it was discovered that the loads on three associated pipe supports were above the support's capacity. The system has therefore been declared inoperable.

This condition was pror ptly reported on August 1, 1980 under Section 6.9.1.8.1 of the Davis-Besse Nuclear Power Station Technical Specifications, Appendix A.

Additional details were provided in Revision 1 to our LER 80-048 fowarded on August 7, 1980.

The occurrence was reviewed with our architc_t engineer, Bechtel Power Corp-oration. An audit and review of all stress calculations used to assess the t

operability of normally accessible safety related piping systems was performed.

This condition was verified as the only isolated instance associated with this effort.

e

. THE TOLEDO EDISON COMPANY EDISON PLAZA 300 MADISON AVENUE TOLEDO OHIO 43652 800gggg \ l7f

Docket No.59-346 License No NPF-3 Serial No. 1-158 August 18, 1980 A new pipe support is being added to the system, prior to Mod 2 2 operation.

This will reduce the loads on the three affected suprorts to within acceptable levels.

Yours very truly,

/f RPC:CLM Sj cc:

U.S. Nuclear Regulatory Commission Office of Inspection and Enforcement Division of Reactor Operation Inspection Washington. D.C. 20555 U.S. Nuclear -6ulatory Commission Office of Nuclear Reactor Regulation Division of Operation Reactors Washington, D.C. 20555