ML19260C429
| ML19260C429 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 12/04/1979 |
| From: | Harold Denton Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19260C428 | List: |
| References | |
| NUDOCS 7912260350 | |
| Download: ML19260C429 (6) | |
Text
- DD 79-23
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Ngyd UNITED STATES OF AMERICA E
NUCLEAR REGULATORY COMMISSION gG Yh 6
0FFICE OF NUCLEAR REACTOR REGULATION HAROLD R. DENTON, DIRECTOR 4
In the Matter of
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)
COMMONWEALTH EDIS0N COMPANY
)
Docket Nos. 50-373 (LaSalle County Station,
)
50-374 Units 1 & 2)
)
DIRECTOR'S DENIAL 0F REQUEST UNDER 10 CFR 2.206 By petition dated August 21, 1979, Jan L. Kodner, Esq., on behalf of Citizens Against Nuclear Power, et al., (hereinafter CANP), requested, pursuant to 10 CFR 2.206 of the Comission's regulations, that the Director of Nuclear Reactor Regulation and/or the Director of the Office of Inspection and Enforce-ment institute a proceeding to suspend or revoke Commonwealth Edison Company's construction pemits for the LaSalle County Station, Units 1 and 2.
Because the nature of the request is more appropriately within the jurisdiction of this office, I have considered the request for possible action.
I The basis of CANP's request is the fact that Commonwealth Edison did not explicitly consider, in the original design for the LaSalle facil.ity, the hydro-dynamic loads that result from the dynamic effects of drywell air and steam being rapidly forced into the suppression pool during a postulated loss-of-coolant 1618
.532 7012260 35G
. accident. CANP requested the construction permits be revoked until confirmatory review of design changes being implemented to accommodate these newly analyzed hydrodynamic loads are completed. Their concern is that construction of the reactors may be proceeding without a determination by the Licensee and the Nuclear Regulatory Commission as to exactly which " vital design specifications" t'e plant should be built.
n On the basis of the information submitted by CANP, I have conducted a review of our acceptance criteria for and the design modifications being made to the Mark II containment system in general and the LaSalle County Station in particular. For the reasons set forth below, I have determined that no suspension or revocation of the construction permits for the LaSalle County Station is presently justified.
II The containment system for the LaSalle Ccunty Station includes a Mark II type containment structure that utilizes the prasure suppression concept to mitigate the consequences of a postulated loss-of-coolant accident (LOCA), that is, a hypothetical accident which the plant is designed to withstand without causing ha m to the public health and safety.
During large scale testing of the Mark III containment system design in the period 1972 through 1974, new suppress-ion pool hydrodynamic loads associated with a postulated LOCA were identified.
These new loads had not been explicitly considered in the original design of the LaSalle or other Mark II containments.
In response to the identification of these new loads, the Nuclear Regulatory Commission, in April 1975, requested each 1618 333
. of the domestic utilities owning a boiling water reactor facility with the Mark II containment design to provide information which would demonstrate the adequacy of their containment designs. Commonwealth Edison Company, to-gether with the owners of all the other nuclear power plants using the Mark II design, formed a group which developea a program consisting of both analytical and experimental tasks to support' their pool dynamic loads application methods.
In November,1975, the Owners group submitted to the Coanission Revision 0 of the Dynamic Forcina Function Report (NED0-21062) describine the generic methodo-logy which would be used to determine the Mark II system pool dynamic loads.
In May 1977, the Owners group divided their ongoing program into two parts:
a Lead Plant Prog am (that includes the LaSalle, Zimmer and Shoreham facilities) and a Long Term Program that includes the remaining Mark II plar.s.
The purpose of the Lead Plant Program was to demonstrate that a sufficient understanding of the pool dynamic phenomena exists and to establish conservative estimates of the greatest hydrodynamic loads likely to be sustained by the Mark II system in the event of a LOCA.
Commonwealth Edison and the other Mark II owners have now com-pleted the Lead Plant Program and have established conservative estimates of the hydrodynamic loads of which the Mark II containmant systs.ns must be designed to withstanc..
The second part of the Mark II Owners group program to study hydrodynamic loads, the Long Term Program (scheduled for completion in October 1980), has two basic objectives. First, it is designed to provide additional confirmation 1618 334
. of certain loads developed and utilized in the Leaa Plant Program. Secondly, it is designed to develop information, by means of tests and analyses, to support possible reductions in selected design basis loads which were used by the Lead Plants. Preliminary results from the Long Term Program indicate that the bounding load specifications established for the design of the Lead Plant containment systems are, indeed, conservative (See Supplement I to NUREG-046; to be issued in December 1979. A copy of this report will be for-warded when it is available.)
These results also suggest that many of the conservative loads required for use in the evaluation of the adequacy of the Lead Plants containment systems can be reduced at the conclusion of the Long Term Program for plants utilizing Mark II type contaianent.
The staff has reviewed ano evaluated the information developed by the Mark II Owners group in its Leaf Plant Program.
The staff's evaluation and the acceptance criteria that were based on that evaluation are set forth in NUREG-0487, dated October 1978.
A copy of this document is attached to this Decision. ( A supplement to the above, Supplement 1 to NUREG-0487, will be issued in December of this year.) The LaSalle County Station, Units 1 & 2, is being designed to meet the Commission's acceptance criteria. Any modifications of the LaSalle facility will be reviewed by the staff and must be approved prior to issuance of the operating license.
1618 335
. III Based on the foregoing, I have concluded that sufficient acceptable information now exists to establish conservative hydrodynamic loads and to evaluate the adequacy of the response of the LaSalle facility to these loads.
The results of the Long Term Program confirmatory review are not required for an adequate evaluation of the Mark II design at the LaSalle facility. Conse-quently, CANP's request for suspension or revocation of the construction pennits held by Comonwealth Edison Company for the LaSalle County Station, Units 1 and 2 is denied.
A copy of this Decision will be placed in the Commission's Public Document Room at 1717 H Street, N. W., Washington, D. C. 20555 and the local public document room for the LaSalle County Station, located at Illinois Valley Coniaunity College, Rural Route #1, Oglesby, Illinois 16348.
A copy of this Decision will also be filed with the Secretary of the Commission for its review in accordance with 10 CFR 2.206(c) of the Comission's regulations.
As provided in 10 CFR 2.206(c) of the Commission's regulations, this Decision will constitute the final action of the Comission 20 days after the 1618 336
. date of issuance, unless the Comission on its own motion institutes the review of this Decision within that time.
FOR THE NUCLEAR REGUALT0RY COMMISSION Alf Y
Harold R. Centon, Director Office of Nuclear Reactor Regulation ed NM Dated at this WA. cay of Quwb
,1979.
Enclosure:
NUREG-0487 1618 337
.