ML19241B079
| ML19241B079 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 07/29/1975 |
| From: | Beratan L NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Thornburg H NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| Shared Package | |
| ML19241B068 | List: |
| References | |
| NUDOCS 7907110654 | |
| Download: ML19241B079 (2) | |
Text
l UN8 T E D STATES i
NUCLEAR REGUL ATORY COMMISSION nrcion si 230 PE ACHTR EE STR E ET, N. W.
LUITE 388 ATL AN T A, CEOH GI A 30333 JUL 2 91975
> t.
H. D. Thornburg, Chief, Field Support and Enforcement Branch, Office of Inspection and Enforcement, Headquarters IRU:
C. E. Murphy, Chief, Facilities Construction Branch, Office of M-Inspection and Enforec=ent; Region II PUMPHOUSE SETTLEMENT, KORTH N!NA 1/JiD 2 - VIRGINIA ELECTRIC & POWER COMPANY, DOCKET NOS. 50-338 RfD 50-339 In response to W. P. Ellis' request for additional information concerning stress in the service rater lines to L' nits 1 and 2 resulting from pucphouse cettlencat, attached is a copy of R. L. Ferguson's stur.ary of cceting between the licensee and his conr a ants and DRL and their consultants dated Tu'.y 17, 1975 and VEPC0 letter, Serial No. 521C, dated July 10, 1975.
The prelinicary data indicated that the stress level in the piping system from a one inch settlecent of the purphouse after the pipes were welded into position sould be only 2300 psi.
This value was challenged and the analysis was considered crude by this inspector since it did not adequately reflect the proper restraints, the pipe geocetry, or the soil pipe interaction.
In preparation for the July 8, 1975 ceeting, the licensee's consultant, Stone and Webster Engineering (SSU), reanalyzed the piping as beams on an clastic foundation factoring in the soil interaction and t_he system config-uration.
As a result of sore preliminary investigation, S&W stated at the meeting that the stresses in the pipe are above code allowable.
In addition, the reanalysis indicated that other stresses will be superimposed from a very large torque (esticated to be approxicately 1,100,000 ft. lbs.) that will result from the differential settlement.
The exact stress values are not available at this tice, but it was S6W's opinion that a redesign of the pipe systen nay be necessary.
Eased upon the reanalysis, this problem was considered by VEPCO to be a reportable
- cm under provisions of 10 CFR 50.55(c) as stated in their letter of July 10, 1975.
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L. L. Ecratan, Senior Inspector Engineering Section
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Enclosure:
O Su=ary of c:eeting cc w/cncl:
W. P. Ellis, IE:llQ G.
C.'
Cower, IE:IIQ R. L. Ferguson, Project Mgr. DRL 307 325
.