ML20010F583
| ML20010F583 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 07/31/1981 |
| From: | Nelson T LAWRENCE LIVERMORE NATIONAL LABORATORY |
| To: | Chen P Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20010F580 | List: |
| References | |
| SM-81-206, NUDOCS 8109100382 | |
| Download: ML20010F583 (3) | |
Text
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ENCLOSURE 2
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l Lawrenca Livermora National Laboratory 1
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July 31, 1981 SM 81-206 Mr. P. Y. Chen Systematic Evaluation Program Branch Division of Licensing Office of Nuclear Reactor Reg.
U.S. Nuclear Regulatory Commission Washington, D.C.
20555
Dear P. Y. :
I have enclosed two letters from W..J. Hall regarding continued operation of Yankee Rowe and Haddam Neck plants. The seismic input issue raised in the Yankee Rowe letter is being reviewed by Don Bernreuter of LLNL. He will be corresponding with the SEP Branch Staff on this issui. in the next few days.
In addition, I am transmitting D. A. Wesley's latest evaluation of Haddam Neck's program plan.
Sincerely, Thomas A. Nelson Structural Mechanics Group Nuclear Test Engineering Division TAN /mg 0077m Enclosure 8109100382 810904 gDRADOCK 05000029 PDR An EM Ooow:mitEnctryv e ltuvs.tiof Cah!xn,a PO Bax SOE Lamare Ca'ttna 945S0
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WILLIAM
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July 25, 1981 Mr. T. A. Nelson L-90 Lawrence Livermore Laboratory P. O. Box 808 Livermore, CA 94550 Re:
Yankee Rowe Nuclear Power Plant -- Docket No. 50-29 LLL Agreement 1523501
Dear Mr. Nelson:
Comments arising from my further review of the Yankee Rowe Nuclear Power Plant and in particular topics pertaining to its ability to accommodate
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seismic effects follow.
Reference is made to a letter of 11 Noyember 1980 from Dr. Newmark and me in which we listed the reports that we had in hand at that time and asked a number of questions pertaining'to the forthcoming site visit and meetings to be held with the licensee.
Subsequently on 12 December 1980 I made a visit to the site of Yankee Rcwe for purposes of inspecting the facility and held brief discussions with the Yankee Atomic Electric Company personnel and their consultants.
Shortly thereafter on 17 December 1980 Dr. Newmark and I attended a meeting in Washington', D. C. at which time the Yankee Atomic Electric Company personnel and their consultants presented the status of their current studies with regard to the Yankee Rowe Plant.
The This past week I received a copy of Report YAEC-1263 dated ' June 1981.
composite spectrum presented therein appears deficient in both the acceler-ation and velocity controlled regions. This deficiency may be due to the use of median centered coefficients, which to me do not seem appropriate in this case, and possibly to the lack of recorded effects from distant earth-It is 'my belief that distant earthquakes need careful consideration
' quakes.
at sites such as this one, especially in view of the nature of the facility.
For example, while in Canada last week discussing the design of the Alaska-Canada gasline I was told that the recent northern Kentucky earthquake led With to significant shaking of high-rise buildings in Toronto, Canada.
regard to the composite spectrum it is difficult for me to understand the basis for employing superposition of two different approaches, as described on P. 30 and elsewhere in Report YAEC-1263. Over and above the foregoing, I have great concern in accepting a spectrum anchored at 0.1 g for this It is important to n'o'te site for full-tenn nuclear power plant operation.
that the plant site falls in Zone 2 of the 1979 tlBC and in Map Zone 3 of Although these standards are not applicable to nuclear power ATC-03.
plants they do indicate the need for significant seismic resistance for even routine structures.
g In the very near tenn, in my view, it is imperative to resolve the signifi-cant differences between the site specific seismic studies reported by the licensee in Report YAEC-1263 and those of USNRC/ TERA.
At present it is my belief that the 0.19 g ZPA spectrum anchor pois.t associated with the USNRC/
TERA criteria is more closely characteristic of the value that should be employed for the longer term upgrading.
I am aware that it is believed'that the site has apparently experienced o11y light seismic excitation during the past 200 years or so.
It is my understanding from the discussion at the 17 December 1980 meeting and sub-sequent discussion with NRC staff that the reactor building columns and the steam generator supports were modified (retrofitted) recently to cri-teria corresponding to Reg. Guide 1.60 spectra (84.1 percentile) anchored to 0.1 g.
This spec +. rum fails to achieve the levels of response of the site specific spectra approved by USNRC in June 1981 for this site. With appreciation for the basis upon which the USNRC/ TERA site specific spectra were generated, I do wish to note that Dr. Newmark (prior to his death) and I expressed concern to W. Russell and T. Che'g of USNRC verbally that in some cases (including this case) the amplified acceleration and velocity regions appeared to be low when compared to standard Reg. Guide 1.60 or NYREG CR/0098 spectra that we normally would recommend for use. As a re-sult of this observation, and also since this is an older operating plant, whe' reviewing the physical resistance of critical safety systems in such cases as this, I recomend that particular attention be paid to the strength margins that may be present to resist overloading from seismic effects.
f The studies summarized in the 17 December 1980 meeting suggest some inherent j
seismic strength exists in the piping systems that had been analyzed for the interim seismic hazard.
Modifications have been completed on the reactor building supporting columns and the steam generator supports as noted above.
Further I am advised that safety related electrical equipment has been exam-ined and anchored.
On the basis of the foregoing observations, and on the assumption that a comprehensive upgrading program for structures, equipment and piping is established and is carried forward promptly and on schedule, to acceptable criteria, I see no reason at this moment why this plant should not be per-mitted to continue in operation in the near term. The technical details of.
upgrading and the upgrading program progress should be monitored carefully by USNRC staff.
Sincerely yours,
/QI/ct(
W. J. Hall WJH:efh cc:
W. T. Russell e