ML20003E078
| ML20003E078 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 03/23/1981 |
| From: | Schwencer A Office of Nuclear Reactor Regulation |
| To: | Nichols T SOUTH CAROLINA ELECTRIC & GAS CO. |
| Shared Package | |
| ML20003E079 | List: |
| References | |
| NUDOCS 8104020207 | |
| Download: ML20003E078 (2) | |
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Local POR LB#2 File Docket No. S0-39S WKane ASchwencer GZeck Mr. T. C. Nichols, Jr.
Vice President & Group Executive Nuclear Operations South Carolina Electric & Gas Company P. O. Box 764 Columbia, South Carolina 29218
Dear Mr. Nichols:
SUBJECT:
ACRS REPORT ON VIRGIL C. SUMMER NUCLEAR STATION A copy of a letter to Chaiman Hendrie dated March 18, 1981 concerning the Advisory Corm 11ttee on Reactor Safeguards' review of your application to operate the Virgil C. Surmer Nuclear Station, Unit 1, is enclosed for your infomation.
Sincerely, original signed by A. Schwencer, Chief
[<'S--.,.*>'N Licensing Branch No. 2
' 'h Division of Licensing
Enclosure:
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1 Mr. T. C. Nichols, Jr.
.Vice President &' Group Executive Nuclear Operations South Carolina Electric & Gas Ceccany P. O. Box 764 Columbia. South Carolina 29218
- cc:. Mr. Henry _Cyrus Senior Vice.Fresident-South Carolina Public Service Authority 223 North Live Oak Drive LMoncks Corner, South Carolina' 29461
' J. B. Knotts, Jr., Esq.
Debevoise & Liberman 1200 17th Street, N. W.
Washington, D. C.
20036 Mr.- Mark B. Whitaker, Jr.
Group Manager - Nuclear Engineering & Licensing South Carolina-Electric & Gas Cc par.y P. O. Box 764-
'Colu=bia, South Carolina' 29218 Mr. Bre'tt Allen Bursey.
Route 1, Box 93C Little Mountain,' South-Carolina - 29076' Resident Inspector /Sumner NPS -
.c/o U. S. NRC Rcute 1, Box 15: -
Jenkinsville.iSouthCarolina. 29065 m
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/pn see UNITED STATES j }; ) g,ig. lt NUCLEAR REGULATORY COMMISSION ADVISORY COMMITTEE ON REACTOR SAFEGUARDS g+sp, WASMNGToN, D. C. 20555 s,*
March 13,1981 Honorable Joseph M. Hendrie Chairman U.S. Nuclear Regulatory Ccmmission Washington, DC 20555
SUBJECT:
REPORT ON VIRGIL C. SUMMER NUCLEAR STATION UNIT 1
Dear Dr. Hendrie:
Ouring its 251st meeting, March 12-14, 1981, the ACRS completed its review of the application of the South Carolina Electric and Gas Company for a license to operate the Virgil C. Summer Nuclear Station Unit 1.
This proj-ect was considered at subcommittee meetings on February 26-27, 1981 in Columbia, South Carolina, and on March 11, 1981 in Washington, D.C.
A tour of the f acility was made by members of the Subconnittee on February 26, 1981.
During its review the Committee had the benefit of discussions with repre-sentatives of the Applicant, the NRC Staff, the U.S. Geological Survey, and of the documents listed.
The Committee reported on the construction permit application for this plant in a letter
- to AEC Chairman Schlesinger dated November 15, 1972.
The Summer plant is located in Fairfield County, South Carolina, about 26 miles northwest of Columbia, South Carolina.
The nearest community with more than 1000 residents is Winnshore, about 15 miles to the northeast.
The plant is adjacent to the Monticello reservoir, which provides cooling water for the main condenser, as well as the ultimate heat sink.
The Summer plant employs a Westinghouse, three-loop, pressurized water, nu-clear steam supply system.
The containment is a cylindrical, carbon-steel-lined, prestressed concrete structure having a design pressure of 57 psig.
At the construction permit review stage, some of the ACRS consultants were reluctant to accept the position of the Regulatory Staff and its consul-tants that the 1886 Charleston earthquake could be clearly localized in the Charleston area with regard to recurrence and recommended that a somewhat increased seismic design basis be employed.
The ACRS supported the Regula-tory Staff position favoring a safe shutdown earthquake (SSE) acceleration of 0.15.
However, in separate reports to the AEC dated May 13, 1971 and 9 1973, the ACRS urged initiation of a seismic research program in-May 16, tended to provide a better understanding of the likely causes of earthquakes near Charleston as well as several other areas in the eastern United States.
Considerable research has since been undertaken in the Charleston area, and an improved understanding of the possible causes of earthquakes in the east-ern United States has been developed.
However, there still exists more than one theory with regard to the ' source of the 1886 Charleston earthquake.
T 4 7/01 h 430 ?
Honorable Joseph M. Hendrie March 18,1981 Since the construction permit stage, a new issue has arisen with regard to the choice of seismic design basis; namely, the potential for a moderate earthquake at the site resulting from reservoir-induced seismicity.
The Applicant has studied seismic activity in the vicinity of the Monticello reservoir since it was filled in 1977, and combined the results of those studies with information about the local geology and hydrology in arriving at the conclusion that a maximum near-field earthquake magnitude of 4.0 should be considered in evaluating plant safety.
The NRC Staff and its consultants have concluded that a near-field magnitude of 4.5 should be used.
However, one member of' the NRC Staff disagrees with the majority Staff position, suggesting that the available information does not rul e out a somewhat larger reservoir-induced earthquake, and that a near-field earthquake having a magnitude of 5.0 to 5.3 should be used for assessing seismic safety.
The ACRS consultants agree that there does not exist a very good basis for choosing a specific near-field event, and generally support the use of a -
near-field magnitude of about five for evaluation of the plant.
Because it is difficult to judge that the probability of significant exceed-ence of the original SSE is sufficiently small, the ACRS has requested, and the Applicant has provided, information that indicates there is sufficient margin in the original design to cope safely with accelerations considerably larger than the SSE of 0.15, including those which might arise from a near-9 field, magnitude 5 earthquake.
The Applicant's results to date regarding seismic design margin are reassur-ing.
The ACRS recommends that these studies by the Applicant be extended to include all systems and components whose function is important to the assurance of the continuing removal of shutdown heat.
Such studies need not be completed prior to operation of the Sommer plant.
The discussions relative to the seismic issues at the Summer Nuclear Power Station raise certain questions that we believe should be addressed.
These questions, which largely pertain to emergency preparedness, include the ability of certain key systems to function after a major seismic event.
Included among such systems are the emergency aiarm features to alert the public to an accident in the plant, meteorological and field radiation mon-itoring networks, communications, and emergency evacuation routes.
As a result of the continuing microseismic activity induced by the reservoir, the Applicant has,- at NRC request, agreed to continue seismic monitoring for at least the next two years.
We recommend that the NRC Staff assure that the monitoring program is not halted prematurely.
In its review of the Applicant's organization and management, the NRC Staff has identified several areas requiring attention, including the size of the engineering organization and the adequacy of ex::erience with nuclear power reactors within the company, including hands-on operating experience within
Honorable Joseph M. Hendrie March 18,1981 the operating organization.
The Applicant has taken steps to obtain the services of outside grouos to provide additional technical capability for the short term while the needed in-house capability is developed.
Care should be exercised that, as part of this effort, sufficient technical breadth and independence exists among the members of the Nuclear Safety Review Committee for the plant.
We have previously recommended that probabilistic safety analyses be per-formed for all plants in operation or under construction.
We believe that this reccmmendation is applicable to this unit, but that such studies need not be perforned prior to licensing of the plaat.
During construction of the essential service water intake structure and pump house, settlement well beyond that predicted was experienced.
While the settlement of the structures appears to have halted, the NRC Staff is still evaluating information addressing the stability of the subsurface materials and foundations of the intake structure and pumphouse.
This matter should be resolved in a manner satisfactory to tne NRC Staff.
The ACRS believes that, if due consideration is given to the items mentioned above, and subject to satisfactory completion of construction and preopera-tional testing, there is reasonable assurance that the Virgil C. Summer Nu-clear Station Unit I can be operated at power levels up to 2775 MWt without undue risk to the health and safety of the public.
Si ncerely,
J. Carson Mark Chairman
References:
1.
South Carolina Electric and Gas Company, " Final Safety Analysis Report, Virgil C. Summer Nuclear Station," Volumes I-XX and Amendments 1-22 2.
U. S. Nuclear Regulatory Commission, " Safety Evaluation Report Related to the Operation of Virgil C. Summer Nuclear Station, Unit No.1,"
USNRC Report NUREG-0717, dated February,1981 3.
Letter from J. Devine, USGS, to R. Jackson, NRC, in response to an NRC request for update on USGS information concerning occurrence of earthquakes similar to the 1886 Charleston event, dated December 30, 1980 4.
Memorandum from A. Murphy, Site Safety Research Branch, NRC, to R.
Jackson, Chief, Geosciences Branch, NRC,
Subject:
Recommendation of Maximum Reservoir-Induced Earthquake at the V. C. Summer Nuclear Station, dated February 6,1980 5.
" Comments from the Palmetto Alliance, Inc., by Michael Lcwe on V. C.
Summer Operating License Application Review by the NRC Advisory Com-
- mittee on Reactor Safeguarcs," dated February 26, 1981 6.
" Testimony Before the Advisory Committee on Reactor Safeguards Related to the Virgil C. Summer Nuclear Station," Ms. Ruth Thomas, received February 25, 1981