ML20003A476

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Order Granting Extended Exemption from General Design Criterion 50 & Directing Licensee to Reassess Suppression Pool Hydrodynamic Loads.Mods Required by 820131
ML20003A476
Person / Time
Site: Peach Bottom Constellation icon.png
Issue date: 01/13/1981
From: Eisenhut D
Office of Nuclear Reactor Regulation
To:
PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
Shared Package
ML20003A477 List:
References
NUDOCS 8102040112
Download: ML20003A476 (7)


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O 7590-01 UNITED STATES OF AMERICA j

NUCLEAR REGULATORY COMMISSION In the Matter of

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PHILADELPHIA ELECTRIC COMPANY,

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ET AL

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Docket No. 50-277 (Peach Bottom Atomic Power

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Station, Unit No. 2)

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ORDER FOR MODIFICATION OF LICENSE AND GRANT OF EXTENSION OF EXEMPTICN I.

Philadelphia Electric Company (the licensee) and three other co-owners are the holders of Facility Operating License No. DPR-44 5 hich authorizes the operation of the Peach Botton Atomic Power Station, U nit No. 2, at steady state reactor power levels not in excess of 3293 mega vatts thermal (rated power). The facility consists of a boiling water reactor located at the licensee's site in Peach Bottom York County, Pennsylvania.

II.

On February 28, 1978, the Commission granted to the licensee an interim j

exemption from the requ*rements of General Design Criterion 50, " Containment

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Design Basis," of Appendix A to 10 CFR Part 50 (Federal Register Vol. 43, No. 61, March 29, 1978). This exemption is related to the demonstrated safety margin cf the Mark I containment system to withstand recently identified suppression pool hydrodynamic loads associated with postulated design basis los;-of-coolant accidents and primary system transients.

'si though there was a reduction in the margin of safety from that called fair by General Design Criterion 50, the Commission found that a sufficiant margin would exist to preclude undue risk to the health and safety of the public for an interim p'eriod while a more detailed review was being conducted.

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' 7590-01 The Commission's evaluation was documented in the NRC staff's " Mark I Containment Short-Tenn Program Safety Evaluation Report," NUREG-0408, dated December 1977, which concluded that the BWR facilities with the Mark I con-tainment design could continue to operate without undue ri;k to the health and safety of the public while a more comprehensive Long-Term Program was being conducted. The purpose of the Long-Tenn Program was to define design basis (i.e., conservative) loads that are appropriate for the anticipated life (40 years) of each BWR/ Mark-I facility, and to restore, the original intended design safety margins for each Mark I containment system. In order to provide uniform, consistent, and explicable acceptance criteria for the Long-Term Program, the Summer 1977 Addenda of the ASME Boiler and Pressure Yessel Code have been used as the basis for defining the interided margin of

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safety, rather than using the particular version of tre ASME Code which was applicable to the initial licensing of each facility. In some instances, the allowable stresses are higher under the later edition of the Code. The basis for acceptance criteria is described in the " Mark 1 Containment Long-Term Program Safety Evaluation Report," NUREG-0661, dated July 1980.

As a result of our review of the extensive experimental and analytical l

programs conducted by the Mark I Owners Group, the NRC staff has concluded that the Owners Group's proposed load definition and structural assessment 1

techniques, as set forth in the " Mark I Containment Program Load Definition Report," NED0-21888, dated December 1978, and the " Mark I Containment Program Structural Acceptance Criteria Plant Unique Analysis Application Guide,"

NE00-24583-1, dated October 1979, (subsequently referred to as NED0-21888 and NED0-24583-1) and as modified in certain details by the. staff's Acceptance t

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. 7590-01 Criteria, will provide a conservative basis for determining whether any struc-tural or other plant modifications are needed to restore the original intended margin of safety in the containment design. The staff's Acceptance Criteria are contained in Appendix A to NUREG-0661. The basis for the staff's requirements and conclusions is also described in NUREG-0661.

Ill.

In letters dated March 12, 1979, each BWR/ Mark I licensee was requested by the NRC to submit a schedule for carrying out an assessment of the need for plant modifications for each of the licensee's BWR/ Mark I units, based on the Owners Group's proposed generic load definition and assessment techniques, and for the subsequent installation of the plant modifications determined to be needed by such an assessment. In response to our letter, the licensee's letter dated June 20,1980 indicated its commitment to undertake plant-unique assessments based on the Owners Group's generic assessment techniques, to modify the plant systems as needed, and also indicated that its schedule for this effort would result in i plant shutdown to complete the plant modifications by January 31, 1982.

On October 31, 1979, the staff issued an initial version of its acceptance criteria t) the affected licensees. These criteria were subsequently revised in February 1980 to reflect acceptable alternative assessment techniques which would enhance the implementation of this program. Throughout the development of these acceptance criteria, the staff has worked closely with the Mark I Owners Group in order to encourage partial plant-unique assessments and modi-fications to be undertaken.

, 1590-01 The modification schedules submitted in response to the March 12, 1979 letter have subsequently been revised to reflect the development of the acceptance criteria and additional infornation concerning plant modift:ations that will be needed to demonstrate conformance with those criteria.

In consideration of the range of completion estima tes reflected by all of the affected licensees and the staff's assessment of the nature of the effort involved in the reas-sessment work and in the design and installation of the needed plant modifica-tions, the staff has concluded that the licensee's proposed completion schedule is both prompt and practicable.

Under the circumstances, the URC staff has determined that the licensee's commitment to undertake the reassessment of suppression pool hydrodynamic loads and to design and complete installation of the plant modifications, if any, needed to conform to the generic acceptance criteria by January 31, 1982 should be confirmed and formalized by Order.

IV.

The Commission hereby extends the exemption from General Design Criterion 50 28, 1978, of Appendix A to 10 CFR Part 50 granted to the licensee on February only for the time necessary to complete the actions required by Section V or Substantial improvements have already been made in the VI of the Order.

margins of safety of the containment systems and will continue to be improved during this period whenever practicable, and, in any event, all needed improve-ments, if any, must be completed in accordance with the provisions of Section V or VI of this Order.

. 7590-01 The Commission has determined that good cause exists for the extension of this exemption, that such exemption is authorized by law, will not endanger life or property or the common defense and security, and is in the public interest. The Commission has determined that the granting of this exemption will not result in any significant environmental impact and that, pursuant to 10 CFR 51.5 (d)(4), an enviromnental impact statement or negative declara-tion and environmental impact appraisal neea' not be prepared in connection with this action.

V.

Accordingly, pursuant to the Atomic Energy Act of 1954, as amended, and the Commission's regulations in 10 CFR Parts 2 and 50, IT IS HEREBY ORDERED THAT the license be amended to include the following conditions:

1.

the licensee shall promptly assess the suppression pool hydrodynamic loads in accordance with NEDO-21888 and NED0-24583-1 and the Acceptance Criteria :ontained in Appendix A to NUREG-0661.

2.

any plant modifications needed to assure that the facility conforms to the Acceptance Criteria contained in Appendix A to NUREG-0661 shall be designed and its installation shall be completed not later than January 31, 1982 or, if the plant is shutdown on that date, before the resumption of power thereafter.

VI.

The licensee or any person whote interest may be affected by the Order set forth in Section V hereof may request a hearing within thirty days of the date of publi-cation of this Order in the Fgleral Register. Any request for a hearing shall be addressed to the Director, Off'ce of Nuclear Reactor Regulation, U. S. Nuclear

- 7590-01 Regulatory Commission, Washington, DC 20555, and to Troy B. Conner, Jr., Esquire, 1747 Pennsy,,ania Avenue, NW, Washington, DC 20006, attorney for the licensee.

If a hearing is held concerning such Order, the issues to be considered at the hearing shall be:

1.

whether the Itcensee should be required to promptly assess the suppression pool hydrodynamic loads in accordance with the requirements of Section V of this Order; and, 2.

whether the liceriee should be required, as set forth in Section V of this Order, to complete the design and installation of plant modifications, if any, needed to assure that the facility conforms to the Acceptance Criteria contained in Appendix A to NUREG-0661.

The Order set forth in Section Y hereof will become effective on expiration of the period during which the licensee nay request a hearing or, in the event a hearing is held, on the date specified in an order issued following further proceedings on this Order.

VII.

For further details concerning this action, refer to the following documents which are available for inspection at the Commission's Public Docunent Room at 1717 H Street, NW, Washington, DC 20555 or through the Comnission':; local public document room at the Government Publications Section, State Library of Pennsylvania, Education Building, Commonwealth and Walnut Streets, Harrisburg, Pennsylvania 17126:

1.

" Mark I Containment Program Load Definition Report," General Electric Topical Report, NED0-21888, December 1978.

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" Mark I Containme..'_ Program Structural Acceptance Crite-ia Plant Unique Analysis Applications Guide," General Electric Topical ~eport, NEDO-24583-1, October 1979.

3.

" Mark I Containment Long Term Program Safety Evaluation Report,"

NUREG-0661, July 1980.

4.

Letter from J. S. Kemper, Philadelphia Electric Cocpany, to R. W. Reid, NRC, dated June 20, 1980.

5.

Letter to licensee dated January 13, 1981.

F R THE NUCLEAR REGULAT]RY COMMISSION M

Darrell G. E enhut, Di-e:ter Division of Licensinc Office of Nuclear Reactor Regulation Dated:

vanua ry 13, 1981 Bethesda, Maryland e

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