ML19341B110
| ML19341B110 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 01/13/1981 |
| From: | Eisenhut D Office of Nuclear Reactor Regulation |
| To: | COMMONWEALTH EDISON CO. |
| Shared Package | |
| ML19341B111 | List: |
| References | |
| NUDOCS 8101300244 | |
| Download: ML19341B110 (7) | |
Text
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7590-01 UNITED STATES OF. AMERICA NUCLEAR REGULATORY COMMISSION In the Matter of
)
. COMMONWEALTH EDISON COMPANY
)
(Dresden Nuclear Power Station,
)
Docket No. 50-237 Unit 2)
)
)
ORDER FOR MODIFICATION OF LICENSE AND GRANT OF EXTENSION OF EXEMPTION I.
Commonwealth Edison Company (the licensee) is the holder of Provisional Operating License No. DPR-19 which authorizes the operation of the Dresden Nuclear Power Station, Unit 2 at steady state reactor power levels not in excess of 2527 megawatts thermal (rated power). The facility consists of a boiling water reactor located at the licensee's site in Grundy County, Illinois.
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II.
f On February 28, 1978, the Commission granted to the licensee an interim exemption from the requirements of General Design Criterion 50, " Containment 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 of the Mark I containment syster to withstand recently identified suppression pool hydrodynamic loads associated with postulated design basis loss-of-coolant accidents and primary system transients. Although there was a reduction in the margin of safety from that called for by General Design Criterion 50, the Commission found that a sufficient margin would exist to preclude undue risk to the health and safety of the public for an interim perio.d while a more detailed review was being conducted.
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i 7590-01 The Commission's evaluation was documented in the NRC staff's " Mark I Containment Short-Term Program Safety Evaluatio' 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 risk to the health and safety of the public while a more comprehensive Long-Term Program was i
being conducted. The purpose of the Long-Term 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 Vessel Code have been used as the basis for defining the intended margin of safety, rather than using the particular version of the ASME Code which was applicable to the initial licensing of each facility.
In some instances, the allowable stresses are higher un er t e later edition of the Code. The d
h basis for r.cceptance criteria is described in the " Mark I Containment Long-Term Program Safety Evaluation Report," NUREG-0661, dated July 1980.
As a result of our review of the extensive experimental and analytical I
programs conducted by the Mark I Owners Group, the NRC staff has concluded that the Owners Group's proposed load definition and structural assessment 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,"
NED0-24583-1, dated October 1979, (subsequently referred to as NEDO-21888 and NED0-24583-1) and as modified in certain details by the staff's Acceptance
. 7590-01 Criteria, will provide a conservative basis for determining whether any struc-tural o* other plant modifications are needed to restore the original intended nargin 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.
III.
In letters dated March 12, 1979, each BWR/ Mark I licensee was requested by the NRC to submit a schedule for carrying out an assessraent 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 letters dated May 11, 1979 and July 2,1980 indicated a commitment to undertake plant-unique assessments based on the Owners Group's generic assessment techniques, to nodify the plant systems as needed, and also indicated.that its schedule for this effort would result in a plant shutdown to complete the plant modifications by January 31, 1983.
On October 31, 1979, the staff issued an initial version of its acceptance criteria to the sffected 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 ccceptance 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.
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L 4-7590-01 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 information concerning plant modifications that will be needed to demonstrate conformance with those criteria. In consideration of the range of completion estimates reflected by all of the affected ifcensees 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 NRC 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, 1983 should be confirmed and formalized by Order.
IV.
The Commission hereby extends the exemption from General Design Criterion 50 l
of Appendix A to 10 CFR Part 50 granted to the licensee on February 28, 1978, only for tha time necessary to complete the actions required by Section V or l
VI of this Order.
Substantial improvements have already been made in the margins of safety of the containment systems and will continue to be improved j
during this period whenever practicable, and, f r. any event, all needed improve-l ments, if any, must be completed in accordance with the provisions of Section V or VI of this Order.
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. 7590-01 The Commission has determined that good cause exists for the extension of this extmption, 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 wil.1 not result in any significant environmental impact and that, pursuant to 10 CFR 51.5 (d)(4), an environmental impact statement or negative declara-tion and environmental impact appraisal need not be prepared in connection with this action.
V.
Accordingly, pursuant to the Atomic Energy Act of 1954, as amended, and the Commissions regulations in 10 CFR Parts 2 and 50, IT IS HEREBY ORDERED THAT the license be amended to include the following conditions:
the licensee shall pranptly assess the suppression pool hydrody.,amic 1.
loads in accordance with NEDO-21888 and NEDO-24583-1 and the Acetptance Criteria contained in Appendix A to NUREG-0661.
any plant modifications needed to assure that the facility conforms to 2.
the Acceptance Criteria contained in Appendix A to NUREG-0661 shall be designed and its installation shall be completed not later than January 31, 1983 or, if the plant is shutdown on that date, before the resumption of power thereafter.
VI.
The licensee or any person whose ir,terest 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 Federal Register.
Any request for a hearing shall be addressed to the' Director, Office of Nuclear Reactor Regulation, U. S. Nuclea.r
. 759C 1
Regulaton/ Comt.ission, Washington, DC 20555, and to Isham, Lincoln & Beale, Counse-lors at Law, One First National Plaza, 42nd Floor, Chicago, Illinois 60603, 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 licensee should be required to promptly assess the suppression pool hydrodynamic loads in accordance with the requirements of Section V of this Order; and,
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2.
whether the licensee 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
.eptance Criteria contained in Appendix A to NUREG-0661.
The Order set forth in Section V hereof will become effective on expiration of the period during which the licensee may 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 Document Room at 1717 H Street, NW, Washington, DC 20555 or through the Commission's local public document room at the Morris Public Library, 604 Liberty Street, Morris, Illinois 60451.
" Mark I Containment Program Load Definition Report," General Electric Topical 1.
Report, NED0-21888, December 1978.-
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.- 7590-01 2.
" Mark I Containment Program Structural Acceptance Criteria Plant Unique Analysis Applications Guide," General Electric Topical Report, NED0-24583-1, October 1979.
3.
" Mark I Containment Long Term Program Safety Evaluation Report,"
NUREG-0661, July 1980.
4.
Letter from C. Reed, CECO, to D. G. Eisenhut, NRC, dated May 11, 1979.
5.
Letter from C. Reed, CECO, to D. G. Eisenhut, NRC, dated July 2,1980.
6.
Letter to licensee dated January 13, 1981.
F}R THE NUCLEAR REGULATORY COMMISSIO Darre
'se hu,
irector Division o Licensing Office of Nuclear Reactor Regulation Dated: January 13.19B1 Bethesda, Maryland 1
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