ML19242B875

to Rept on Reanalysis of Safety-Related Piping Sys.

ML19242B875
Person / Time
Site:	Beaver Valley
Issue date:	08/03/1979
From:	STONE & WEBSTER ENGINEERING CORP.
To:
Shared Package
ML19242B872	List: ML19242B871 ML19242B875
References
NUDOCS 7908090483
Download: ML19242B875 (7)

Text

BEAVER VALLEY POWER STATION, UNIT 1 Revision 4

]NSTRUCTIONS FOR ADDING REVISION 4 TO Tile REPORT ON Tile REANALYSIS OF SAFETY-RELATED PIPING SYSTEMS The following listing will serve as a checklist for entering the attrched pages into the report. The items listed in the " REMOVE" c olt.mn should be removed from the report and replaced with the items in the " ENTER" column.

Vertical bara (cha1ge bars) have been placed in the outside margins of revised text pages and tables to show the location of any technical changes or'ginating with this amendment. Some pages bear a new amendment designation, but no change bars, because revisions on other pages in that section caused a text shift. A fev unrevised pages have been reprinteu because they fall within a run of closely spaced revised pages. No change bars are used on figures or on new sections, appendicee, questions and responses, etc. Change bars from previcus amendments have been deleted on pages revised by this amendment. The iratruction sheet and cover letter should be filed at the beginning of the report.

REMOVE ENTER Title Page Title Page p 1-1 p 1-1 p 5-1 thru 5-2 p 5-1 thru S-2 Table 5-1 (page 6 of 7) Table 5-1 (page 6 of 7)

Table 5-2 -

p 6-2 p 6-2 C.

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3EAVER VALLEY POWER STATION, UNIT 1 REPORT ON THE REANALYSIS OF SAFETY-RELATED PIPING SYSTEMS FOR BEAVER VALLEY UNIT 1 DUQUESNE LIGHT CO:!PANY ORIGINAL - JUNE 15, 1979 REVISION 4 - AUGUST 3, 1979 n' \ n JC Stone 8 Webster Engineering Corporation Boston, Massachusetts

BE AVEp. V ALLEY PC'JER d! ATION , UNIT 1 SECTION 1 SU.TfARY AND CONCLUSIONS In response to the Nuclear Regulatory Commission's Order to Show Cause, dated March 13, 1979, a reanalysis is being conducted of safety-related piping systems which were originally dynamically analyzed using the SHOCK 2 computer program. This program, which used an earlier load combination methodology, is no longer considered acceptable by the NRC. This report spacifically addresses the return to opera'. ion f or an interim period which is defined as the period during which the remaining 6 to 7 weeks of nuclear fuel in the first cycle is expended. T'te r.inor modifications required to ensure that all required pipe stresses are sithin licensed code allowables for the DBE case will be ccmpleted prior to startup for interim operation. Similarly, all modifications required te ensure that the stresses in all pipe supports are within acceptable allavables for the DBE case vill be completed prior to rtartup.

Any modifications to pipe supports that are required to satisfy the OBE requirements will be made during the refueling outage that vill commence as soon as the present nuclear fuel is expended.

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BEAVER VALLEY FOk'ER STATION, UNIT 1 SECTION 5 PIPE SUPPORT RESULTS Table 5-1 summarizes the pipe supports evaluated in the reanalysis program.

There are 1060 pipe supports on lines within the interim reanalysis effort; of these, 666 have been evaluated and found acceptable and 8 have been modified to be acceptable. A support is considered acceptable if all the load components ara lower in magnitude than those for which the support was originally designed. If some load components are greater than the original design load components, the support is reanalyzed using the new loads. Of the total 386 supports requiring reanalysis, all have been found to be acceptable based on DBEI+DL, or the use of one time load for snubbers.

If a support is unacceptable using either of the above approaches, a modification is required. Hardware modifications and additions are discussed in Section 6.

Support designs which are not in a with either of these criteria vill

^ i criteria of Table 3-1 prior be suitably modified against the am -r .s to interim plant operation.

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5-1 Revision 4

BE AVER VALLEY FO'JER STATION, UNIT 1 3ase plate design criteria and an: hor bolt pullout and shear allowable loads are addressed in Section 3. The seismic support icadings which will be utilized for the NT evaluation vill be the result of either SHOCK 3 or NUPIPE evaluations using SSI-ARS.

Summary The pipe support reanalysis effort which took place between the original issue of this report and this revision includes accepting 380 supports; 193 based on DDEI+DL and 187 based on long-term criteria. Also, one additional modification was necessary for the 14" RHR line off the reactor coolant loop, one additional support was required on the 24 inch header from the component cooling heat exchangers, and one support was deleted from the river water system.

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BEAVER VALLEY PO'JER STATION, UNIT 1 TABLE 5-1 (Cont)

No. Fresently Total No. Acceptable No. Acceptable Modifications Systen/ of Eased on for Interim or Additions Problen No. Supoorts Reanalysis Operation Reauired 2031 9 9 0 0 121 15 0 la I 122 19 0 19 0 165 1 0 1 0 152 8 8 0 0 652 1 0 1 0 65355' 2 0 2 0 Main Ste n 658 6 6 0 0 6590 3 3 0 0 101

• 4 0 0 659 2 2 0 0 660 7 7 0 0 3C63 0 0 0 0 Teeduater 204 15 15 0 0 783 9 9 0 0 784 6 6 0 0 785 3 3 0 0 261 6 6 0 0 p_i_esel Generatgr Exhaust 651 2 0 2 0 6 of 7 Revision 4 il g' ma Cp .

BEAVEF VALLEY PC'JER STATION, UNIT 1 Fc11 cuing reanalysis of Problem No. 833, an additional snubber was designed and vill be installed to alleviate a pipe overstress occurring under upset (nDE) and faulted (DBE) conditions.

Similarly, an additional snubber was designed and will be installed in Problem No. 21' to alleviate a pipe overstress occurring under the same conditions.

Three supports in Problem No. 123 vill be modified, one to make the as-built condition agree with the original design, one to strengthen a marginal original design, and one to alleviate an overstressed weld in the support resulting from scismic uplift forces.

9 Similarly, four supports in Problem No. 6533 vill be modified, three to make the as-built condition agree with the original design, and one to alleviate an overstressed member in the support resulting from seismic forces.

A new support is being added adjacent to an existing support in Problem No. 270 in order to relieve a local overstress in a lug.

One support in Problem 121 is being removed to permit the remaining supports to better accommodate the system's design loadings.

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(ll) 6-2 Revision 4