ML20140B534

Recommends That Facility Continue Operation While Upgrading SEP Program.W/O as-built Analyses,Estimation of Margins for Seismic Overload Cannot Be Made

ML20140B534
Person / Time
Site:	La Crosse File:Dairyland Power Cooperative icon.png
Issue date:	06/18/1981
From:	Hall W AFFILIATION NOT ASSIGNED
To:	Russell W Office of Nuclear Reactor Regulation
Shared Package
ML20140B532	List: ML20140B527 ML20140B534
References
NUDOCS 8109140230
Download: ML20140B534 (5)

Text

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r WILLIAM J. HALL 3 805 VALLEY OROOK DR CHAMPAIGN (LLINOIS 6 5 020 217 356 0663

June 18, 198.1 Mr. William T. Russell, Chief Systematic Evaluation Program Branch Division of Licensing Office of Nuclear Reactor Regulation '

U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Re: Lacrosse BWR -- Docket No. 50-409 LLL Agreement 1523501 .

Dear Mr. Russell:

In early March 1981 I received the failowing material for review or information purposes:

1. " Seismic Evaluation of the Lacrosse Boiling Water Reactor" Prepared by Gulf United Services, Elmsford, N. Y. for Dairyland Power Cooperative, Lacrosse. Wisconsin, Jan. 11,1974

2. " Seismic and Stress Analysis of LACBWR Main Steam Piping System " .

Prepared by Nuclear En'ergy Services for Dairyland Power Coopera-tive, August 1, 1975

3. " Seismic and Stress Analysis of the LACBWR High Pressure Core Spray Suction Line Piping System," ibid, July 1976

- 4. " Seismic and Stress Analysis of the LACBWR High Pressure Core Spray Discharge Line Piping System," ibid, May 1977 i 5. Letter of September 7,1978 from R. A. Milos, NES, Inc., to R. E.

Shimshak, Dairyland Power Cooperative, re Seismic Analysis Flow Chart

6. " Licensee's Answers to Order to Show Cause," Dairyland Power Cooper-l ative, an answer to USNRC Show Cause Order of February 25, 1980 (Re: Liquefaction) *

7. " Response to NRC Concerns on Liquefaction Pot 6ntial at Lacrosse Boiling Water Reactor (LACBWR) Site near Genoa, Vernon County, j9140230a'io904 p ADOCK 05000409

. PDR

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2 Wisconsin," Prepared by Dames and Moore, Washington, D. C.,ffarch 21, 1980

8. Transcript of Ilearings in the Matter of Dairyland Power Cooperiitive, Docket No. 50-409, llearing dates December 16 and 17,1980, at Lacrosse, Wisconsin ,,

i More recently I received a copy of a letter dated April 21, 1981, directed to Mr. R. E. Shimshak from Mr. Craig Finnan of Nuclear Engineering Services (NES) replying to certain questions raised by the U. S. Nuclear Regulatory Conmission, as well as a copy of a te?cphone conversation record ,

dated 4/29/81 by Jim Shea, USNRC, covering a discussion with Dairyland Power Cooperative (DPC) personnel. Subsequently on May 22, 1981 Dr. T. Cheng and I made a site visit to the Lacrosse Nuclear Power Plant, where we had dis-cussions with the DPC and NES personnel about the ongoing seismic analyses and related studies, and the seismic retrofitting (hardening) that is in progress.

My comments on the foregoing items follow. In reviewing the earlier reports it is important to note the time frame during which the studies were rude, namely 1973-74 and 1975-77. The first study of some of the critical

' systems (Ref.1) indicated that the piping systems were overstressed and that .

The they needed additional supports to accommodate the seismic loadings.

location and amount of overstressing were not clearly evident from the ,eport.

f Another difficulty in interpreting the information presented in Ref.1 arises

)' c frcm the fact that the seismic analyses were made independently without.,om--

bination of normal dead load, live load, other applicable loads and seismic loads. In Summary, as far as can be ascertained, the state of rtress in the ,

as-tuilt piping when subjected to norral and seismic loading is unknown.

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3 Careful review of the later piping system analysis reports (Ref. 2, 3, and 4) indicates that these analyses were made with modified piping systems in that snubbers and restraints were assumed to be added at strategic loca-tions to make the piping systems fall within code allowables. Even so these reports are difficult to evaluate in terms of the amount of stress at crit-ical regions that can be attributed to the seismic input. It is to be noted

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that these analyses were made in the 2-D framework, as noted in the reports and as cited in the letter of April 21, 1981, but that the combination of stresses was by straight addition; thus in many cases one suspects a three dimensional analysis with SRSS combination may meet code allowables in many cases, but this fact remains to be demonstrated.

Unfortunately, without comprehensive as-built analyses, and with the status of later analyses as they. were made, it is difficult at present to evaluate detailed compliance with current SEP upgrade criteria or to esti-mate the margins for seismic overload (over and above the 0.12 g criterion employed.)

As for other factors that might affect the seismic evaluation it was ,

noted in Section 1.2 of Ref. I that the two stacks could possibly collapse or be damaged in the upper level earthquake, but it was concluded that this would not affect safe shutdown; this conclusion'may need checking.

Also it was noted in the same report that bracing may be required in the turbine building outer steel framework, although it is not clear that this would affect safe shutdown.

As the telephone memorandum cited above notes, and as confirmed at /

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4 the time of our visit on llay 22, 1981, on the llPCS system seven of the new pipe restraints have been installed and another 18 are in various stag,es of design, fabrication or installation. We were advised that many of these supports will be installed during the scheduled shutdown"in fiay and June, 1981. At the time of our visit it was indicat,cd that analysis of other piping systems and design of additional restraints, preparatory to up-grading, is currently underway.

It was encouraging at the time of the visit to witness the ongoing activity pertaining to seismic upgrading which includes not only installa-tion of hardware for supporting such items as batteries, piping, valves and gas bottles, but also consists of an ongoing review of electrical equipment and its mounting. In addition a discussion and review of the steam release paths, and alternate sources of cooling water and power (including emer-gency gasoline motor driven water pumps which are on site at the moment) indicate that the plant has some reasonable degree of redundancy in safety systems to enable it to cope with an incident.

The limited inspection suggests a plant that was carefully ergineered B

and constructed with attention to details. As such, the existing facility -

without installed restraints clearly possesses some level of inherent strength to resist earthquake motions. Admittedly there are no analyses to indicate what that level of strength may be.

In view of the recent historical seismic quiescence of the region kn which the site is located, the inherent capacity of the as-built plant to withstand at least some degree of modest shaking, and the ongoing progress e

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5 being made on the SEP program by the owners, it is my reconunendation insofar i

as seismic aspects are concerned, that the owner be permitted to continue operation while the upgrading program is in progress. Clearly the upgrading program should be carried forward rapidly to its full conclusion and should receive careful review by the USNRC. .

Sincerely yours, N-}HA W. J. Hall

/

WJH:pe cc:t. T. Cheng T. A. Nelson l

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