View source for NUREG-0408, Discusses Review of Generic Mark I Containment Short Term Program Conducted by Owners Group.Info Avaiable in NUREG-0408

{{Adams
| number = ML20127P301
| issue date = 02/28/1978
| title = Discusses Review of Generic Mark I Containment Short Term Program Conducted by Owners Group.Info Avaiable in NUREG-0408
| author name = Stello V
| author affiliation = NRC OFFICE OF NUCLEAR REACTOR REGULATION (NRR)
| addressee name = 
| addressee affiliation = AFFILIATION NOT ASSIGNED
| docket = 05000263
| license number = 
| contact person = 
| document report number = GL-78-8, NUDOCS 9212020183
| document type = CORRESPONDENCE-LETTERS, GENERIC LETTERS, GENERIC LETTERS &amp; IE LETTERS TO MULTIPLE PLANTS., OUTGOING CORRESPONDENCE
| page count = 7
}}

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                                     *%'.....                     J'                          february 28, 1978                                      ('
All Operating BWR Licensees (Except for Humboldt)
Gentlemen:
The HRC staf f has completed its review of the generic Mark 1 Containment                        '
Short Term Program conducted by the tiark 1 Owners Group and the associated plant-unique information which you provided with respect to your facility's containment system. The results of our review are documented in the staff's
                                                           " Hark 1 Containment Short Tenn Program Safety Evaluation Report," NUREG-0408, December 1977. A copy of this document is enclosed for your inf ormation.
Based upon our review, we have concluded that licensed Mark I BWR facilities can continue to operate safely, without undue risk to the health and safety of the public; during_ an interim period of approximately two years while a methodical, comprehensive Long Term Program (LTP) is conducted. This conclu-sion has been made based on our determination (1) that the magnitude and character of each of the hydrodynamic loads resulting from a postulated de-sign basis loss of coolant accident (LOCA) have been. adequately defined for use in the Short Tenn Program (STP) structural assessment of the fiark I containment system; and (2) that, for the most probable loads induced by a postulated design basis LOCA, a safety f actor to failure of at least two exists for the weakest structural or mechanical component in the contain-ment system for each operating liark I BWR f acility.
As described in Section IV of NUREG-0408, our evaluation of the capability of your facility's Mark 1. containment system to withstand the recently                         5 identified LOCA-related hydrodynamic suppression pool loads indicates that, although each of the structural and nechanical components of your contain-ment system meet the STP structural acceptance criteria (i.e., a safety factor to f ailure of at least two). the-demonstrated safety margins .of certain components under these loading conditions is less than that which ry to satisfy the requirements of Section III of the AStiE Boiler                :
is ne-and Pressure Vessel Cade. Consequently, we have concluded that the 1
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9212O20183 780228 PDR                ADOCK 05000263                      -,-                                                                    i P                                           PDR                                                                             !
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l                                                                                           demonstrated safety margin of your facility's containment system with respect to such loading conditions does not comply with our current interpretation of " sufficient margin" as prescribed in General Desion Criterion (GDC) 50, " Containment Design Basis", of Appendix A to 10 CFR Part 50. For long term operation of your facility, we will require that the structural and nechanical compor.ents of your facility's con-tainnent systen neet the acceptance criteria of the ASME Boiler and Pressure Vessel Code to the maximum extent practicable for the loads and loading combinations identified in the 11 ark 1 Containment Long Term Program and approved by the NRC staf f.
l                        However, we find that:              (1) your facility's containment system design still retains sufficient margin under present conditions to preclude J
failure and thus provides reasonable assurance of no undue risk to the 1                        health and safety of the public (2) the objective of the flark 1 Con-tainment LTP, i.e. , to restore the originally intended design safety margins for each Mark I containment system, is acceptable, and (3) the 11 ark 1 Owner's Program Action Plan for the LTP is raasonably designed l
to satisfy the LTP objectives. Therefore, we find that operation of your f acility, in conformance with the conditions specified in NUREG-0408, will not endanger life or property or the common defense and security.
In the absence of any safety problem associated with operation of your f acility until the LTP is completed, there appears to be no public interest consideration favoring restriction of the operation of your f ac ili ty. Accordingly, pursuant to 10 CFR Part 50, Section 50.12, you are hereby granted an exemption from GDC-50, with respect to LOCA-related hydrodynamic suppression pool loads, for an interim period until completion of the LTP (approximately two years), provided that the conditions specified in NUREG-0408 and any resulting Technical Specification requirements are maintained. To this extent, this exemp-tion encompasses any related requirements of 10 CFR Part 50, Section 50.55(a), and GDC-1.
A sample FEDERAL REGISTER Notice related to this action is also enclosed
!                         The Notice that is filed with the Of fice of the Federal Register for each individual plant will be provided at a later date.
As discussed in Section Ill.C. of NUREG-0408, operating and surveillance
;                         requirements on drywell/wetwell differential pressure and torus water levels will be incorporated, by license amendment, into your facility Technical Specifications in the near/future,fA)
Vk               ,J              rector Division of 1p                . Reactors Of fice of Nucl     r Reactor ReQulation

==Enclosures:==

j                         See Page 3 I

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==Enclosures:==
: 1. NUREG-0408, '' Mark I Containment                                                                                                           I Short Term Program Safety                                                                                                       )
 '-                                                              Evaluation Report"                                                                                                               i
 ;                                                  2.       federal Register Notice
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SAMPLE FEDERAL REGISTER NOTICE UNITED STATES NUCLEAR REGULATORY COMMISSION
  '                                                                        00CKET NO.
i j                                                                              LICENSEE i
NOTICE OF GRANTING AN EXEMPTION FROM THE I                                               REQUIREMENTS OF GENERAL DESIGN CRITERION 50, 4                                                  " CONTAINMENT DESIGN BASIS" OF APPENDIX A
  '                                                                       10 10 CFR PART 50
!                                 The U.S. Nuclear Regulatory Commission (The Commission) has aranted an
;                                  exemption from the requirements of General Design Criterion 50, "Contain-ment Design Basis", of Appendix A to 10 CFR Part 50 to                                         (Licensee)
                  *                (the Licensee). This exemption relates to the demonstrated safety maroin of the Mark I containment system for                            (Facility Name) for recently identified hydrodynamic supppression pool loads associated
!                                  with a postulated design basis loss of coolant accident and provides for i
j                                  operation under the conditions specified in the NRC staff's " Mark 1 Con-R l                                  tainment Short Term Program Safety Evaluation Report" and under any h                                                                                                            To this extent, this l
resulting Technical Specification requirements.
\
exemption encompasses any related requirements of 10 CFR Part 50, Sec-l                                   tion 50.55(a), and General Design Criterion 1.                          This exemption is effective l
i                                   as of the date of its issuance.
I The Commission has evaluated the demonstrated safety margin of the containment system for                       (Facility Name)              under present-I l
1

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                                  \                                                                    ,
2 conditions and has concluded that sufficient margin exists to preclude undue risk to the health and safety of the public. This evalua-tion is documented in the staf f's " Mark 1 Containment Short Term Program Safety Evaluation Report," NUREG-0408, December 1977.
This exemption is granted for an interim period of approximately two years while a more detailed review is conducted. At the conclusion of this re-view, the design safety margin of the containment systen for               (Facility Name will be restored to that which was originally intended at the time (Facility Name)     was licensed for operation. The basis for this
-          exenption is set forth in the letter to the licensee granting the exemption, dated February         , 1978.
The Commission has determined that the granting of this exemption will not result in any significant environmental impact and that pursuant to 10 CFR Section 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.
For further details with respect to this action, see (1) the Commission's letter to the licensee dated February         , 1978, and (2) the Commission'.
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:                                                                                           3                                                                              .
i                                 " Mark 1 Containment Short Term Program Safety Evaluation Report," NUREG-                                                                !
l                                 0408, December 1977.
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?                                 These items are available for public inspection at the Comission's i
j                                 Public Document Room,1717 H Street, N.W., Washington, D. C. and at the                                                                   -
i j                                                  (LPDR)                               . A copy of item (1) may be obtained i
upon request addressed to the U.S. Nuclear Regulatory Commission, Washino-                                                               ,
l l                                 ton, D.C. 20555, Attention: Director, Division of Operating Reactors.                                                                    .
4                                 A copy of item (2) may be obtained upon request addressed to the National i                                 Technical Information Service, Springfield, Viroinia 22161.
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Dated at Bethesda, Maryland this                                                                           .
l                                                                                    FOR THE NUCLEAR REGULATORY C0titilSS104 1
j'                                                                                                                      , Chief                                            ,
Operating Reactors Branch l
Division of Operatino Reactors i                                                                                                                                                                          ;
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Northern States Power Company CC Gerald Charnoff, Esquire                            The Environmental Conservation Library Shaw, Pittman, Potts and                            Minneapolis Public Library Trowbridge                                       300 Nicollet Mall 1800 M Street, N. W.                                Minneapolis, Minnesota 55401 Washington, D. C. 20036 Arthur Renquist, Esquire Vice President - Law Northern States Power Company 414 Nicollet Mall Minneapolis, Minnesota 55401 Mr. L. R. Eliason Plant Manager Monticello Nuclear Generating Plant Northern States Power Company Monticello, Minnesota 55362 Russell J. Hat 11ng, Chairman Minnesota Environmental Control Citizens Association (MECCA)
Energy Task Force 144 Melbourne Avenue, S. E.
Minneapolis, Minnesota 55414 Mr. Kenneth Dzugan Environraental Planning Consultant Office of City Planner Grace Building 421 Wabasha Street St. Paul, Minnesota 55102 Sandra S. Gardebring Executive Director Minnesota Pollution Control Agency 1935 W. County Road B2 Roseville, Minnesota 55113 i
Mr. Steve Gadler 2120 Carter Avenue St. Paul, Minnesota 55108 Anthony Z. Roisman Natural Resources Defense Council 917 15th Street Washington,D.d.N.W. 20005 f
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