ML19345F578
| ML19345F578 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 01/27/1981 |
| From: | Dircks W NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO) |
| To: | Mark J Advisory Committee on Reactor Safeguards |
| References | |
| NUDOCS 8102180439 | |
| Download: ML19345F578 (2) | |
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."o UNtTED s1 ATES y A isoA h NUCLE /. 4 LATORY COMMISS ON e' 4 oN. o. c. 20sss i
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3 Dr. J. Carson Mark, Chairman C
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Advisory Committee on Reactor Safeguards
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U. S. Nuclear Regulatory Comission Washington, DC 20555
Dear Dr. Mark:
SUBJECT:
STATUS REPORT ON RESTART OF THE THREE MILE ISLAND NIICLEAR STATION, UNIT 1 In Dr. Plesset's letter to the Comission dated December 11, 1980, coments were provided regarding the continuing review of the status of the proposed restart of the Three Mile Island Nuclear Station, Unit 1 (TMI-1). These comments were based in part on infornation presented during the 248th ACRS meeting December 4-6, 1980 and an earlier Subcommittee meeting.
During the 249th ACRS meeting on the afternoon of January 9,1981, we provided our response to the c.wments highlighted in the December 11, 1980 letter. The following is a summary of our position on a few items specifically raised during the January 9th meeting.
The staff has taken the position that the requirements for restart of TMI-1 should contain the items required for near tenn operating licenses (NT0Ls). These requirements were delineated to the licensee by [[letter::05000320/LER-1980-049-01, /01L-0:on 801027,ASME Code Stamped UV Valve LTB-V171 Discovered Stamped by Unauthorized Valve Supply House.Caused by Unauthorized Use of ASME UV Code Stamp by North American Safety Valve Industries,Inc|letter dated November 25, 1980]] from D. G. Eisenhut, NRC, to R. C. Arnold, Met. Ed. These requirements are also listed in Enclosure 2 to NUREG-0737, " Clarification of TMI Action Plan Requirements."
In response to Dr. Plesset's request for a concise summary of the open issues, a consolidated listing of open issues requiring resolution prior to restart is in preparation by the staff. A meeting with the licensee to discuss the status of such open items was held on January 16, 1981. Our summary of open issues will be fealized upon receipt of the licensee's response to our request for commitments b the requirements of NUREG-0737. The ifcensee's response should include many of the requirements specified by the Orders of the Comission dated l
August 9,1979 and March 6,1980, as well as the requirements for NTCLs. This response should be received by February 1,1981.
j With respect to your comments regarding reliability assessments and system l
interaction reviews, the staff intends to pursue your comments in light of our discussions and to obtain cormnitments from the licensee in this area.
As discussed with the Committee, it would be possible to put a time imposition for the completion of these studies in the conditions of the license.
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-.. With regard to D. C. Power Supply Reliability, this topic was discussed on a ger,eric basis during an ACRS Subcommittee meeting on January 22, 1981.
The staff wi.
contue to discuss related site specific issues with the licensee, witn emoru :s on resolving the specific concerns raised by ACRS embers and will then du ide what additional requirements, if any, are warranted.
We believe the actions we are taking are responsive to the cannents outlined in the December 11, 1980 letter and we will be prepared to discuss resolution of these issues during the next ACRS meeting on TMI-1.
Sincerely, (Sig:s5 ?!2:a ]. ]R:2 William J. Dircks Executive Director for Operations
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December 11, 1980 Honorable John F. Ahearne Chairman U.S. Nuclear Regulatory Comission Washington, DC 20555
SUBJECT:
STANSREPORTONRESTARTOFTHETHREEMILEISLANDNUCLEARSTATION, UNIT 1
Dear Dr. Ahearne:
During its 248th meeting, December 4-6, 1980, the Advisory Committee on Reactor Safeguards continued its review of the status of the proposed restart of the Three Mile Island Nuclear Station, Unit 1 (TMI-1) with representatives of the Metropolitan Edison Company (Licensee), General Public Utilities Nuclear Group, the Babcock and Wilcox Company (B&W), and members of the NRC Staff. This matter was also the subject of Subcommittee meetings in Middletown, PA, on January 31 -
February 1,1980, and in '.4shington, DC, on November 28 and 29,1980.
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One of the primary res ltt if th se reviews is an indication of the need for a statement of policy % the NRC on how and when the various components of the Action Plan, the NTOL ';st, and items in the NRC order of August 9,1379, are
'to be applied in the enluation of the TMI-1 restart.
There is also a need for ;.he NRC Staff to prepare a concise summary of the issues tnat remain open on the TMI-1 review, a statement as to the status of each, the degree to which each is considered significant from the standpoint of health and safety, and an indication as to which items must be resolved prior to restart.
For those items whose resolution can be delayed until after restart, there is a need for the specification of a date' when their associated l
review and implementation must be completed.
Because of the importance the l
Committee attaches to this subject, we requested at our meeting on December 4, 1980, that the NRC Staff complete and submit such a summary to the Committee.
l In tems of the response of the Licensee, the ACRS was encouraged by their I
actions in several areas. These include:
(a) the qualifications of management personnel who have been brought into the organization; (b) the thorough, in-l depth training program they have established for their operators and plant support personnel; (c) the program they have developed for keeping up to date on operating experiences elsewhere within the nuclear power industry; (d) the l
degree to which liuman factors considerations have been used in modifying and upgrading the TMI-1 control room; and (e) the commitment of the Licensee to a restart testing program, which includes confirmation of natural circulation.
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2-December 11, 1980 Honorable John F. Ahearne On the basis of its review, the Committee offers the following comments: '
1.
In accordance with our previous recommendations, we believe that the Licensee should conduct reliability assessments of the plant as modified. Such assessments should accelerate the acquisition of potentially significant safety infomation and would expedite the development of the basis for further changes, should they be necessary. They would also provide the Licensee with additional technical insight into the safety of the plant.
In addition, we believe the Licensee should examine the plant from the standpcint of systems interactions that may degrade safety. Although both of these studies should be conducted on a timely basis, their completion should not be a condition for restart.
2.
The Committee has previously recommended that a means be consid-ered which would provide an unambiguous indication of water level in the reactor ;;ressure vessel. Although we do not believe.that installation of such a system should be a requirement for restart, we believe the Licensee should give additional consideration to this matter on a timely basis.
3.
The Committee believes there is a need for instrumentation to mon-itor the position (i.e., opened or closed) of the pressurizer PORV and safety valves in an unambiguous manner. The sensitivity of the currently proposed method to monitor valve position remains an open issue between the Staff and the Licensee. This matter should be resolved in a manner acceptable to the Staff prior to restart.
4.
The Licensee reported on the thermal / mechanical effect of high pres-sure injection on reactor pressure vessel integrity for a small break LOCA with no emergency feedwater flow. This concern, raised by the Bulletins and Orders Task Force, showed a possible conflict between the need for keeping the fuel cool during bleed-and-feed cooling versus keeping the vessel within 10 CFR 50, Appendix G limits.
Although B&W personnel have perfomed calculations relative to this matter, their calculations were limited to the small break LOCA bleed-and-feed procedure. There may be certain accident combina-tions which result in much more severe chilling of the pressure vessel coincident with vessel repressurization. The Committee be-lieves that the Licensee should review a broader spectrum of accident scenarios to assure better bounding of the range of possibilities.
Although these studies should be completed on a timely basis, they need not be a condition for restart.
5.
The Licensee has discussed the consequences of DC power failure at TMI-1 and has evaluated them in a manner similar to that outlin'ed in NUREG-0305, " Technical Report On D.C. Power Supplies In Nuclear Power Pl ants." The Licensee is perfoming additional studies to identify possible events which might lead to the loss of both battery trains.
We encourage completion of these studies on a timely basis.
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Honorable John F. Ahearne December 11, 1980 We will schedule follow-up Subcommittee meetings as soon as practicable and will arrange for the Licensee and NRC Staff to meet with the full Committee when progress warrants.
Additional comments by Messrs. D. Moeller and D. Okrent are presented below.
Sincerely, Milton S. Plesset Chairman Additional Comments by Messrs. D. Moeller and D. Ok-ent In its letter dated December 13, 1979 entitled, " Report on TMI-2 Lessons Learned Task Force Final Report," concerning the topic entitled " Design Features for Core-Damage and Core-Melt Accidents," the ACRS said, "The ACRS supports this i
recommendation. However, the Committee believes that the recommendation should be augmented to require concurrent design studies by each licensee of possible hydrogen control and filtered venting systems which have the potential for mit-igation of accidents involving large scale core damage or core melting. in-ciuding an estimate of the cost, the possible schedule and the potential for reduction in risk."
In its letter dated September 8,1980 entitled " Additional ACRS Comments on Hydrogen Control and Improvement Of Containment Capability," the ACRS reit-erated this recommendation, stating its belief that it, "should be adopted and given priority by the NRC."
We believe that this recommendation is especially applicable to a higher popu-lation density site such as TMI, and that the prior history of an accident at this site reinforces the desirability of examining design measures which have the potential for reducing significantly the quantity of radioactive material released for a range of postulated serious accidents leading to severe core damage or a molten core. We recommend that the restart of Three Mile Island Nuclear Station, Unit 1 be made contingent on a commitment by the Licensee to perform, within a reasonable period following restart, a study such as that recommended in the ACRS letter of December 13, 1979 referred to above.
References:
1.
Metropolitan Edison Company, " Report in Response to NRC Staff Recom-mended Requirements for Restart of Three Mile Island Nuclear Station Unit 1," Volumes 1-3, and Amendments 1-22.
2.
U.S. Nuclear Regulatory Commission, "TMI-1 Restart, Evaluation of Licensee's Compliance with the Short-and Long-Term Items of Section II of the NRC Order Dated August 9,1979, Metropolitan Edison Company, et al., Three Mile Island Nuclear Station Unit 1, Docket 50-289,"
l NUREG-0680, June 1980.
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1 Honorable John F. Ahearne December 11, 1980 References Cont'd:
3.
U.S. Nuclear Regulatory Commission, "TMI-Related Requirements for New Operating Licenses," NUREG-0694, June 1980.
4.
U.S. Nuclear Regulatory Commission, " Clarification of TMI Action Plan Re-quirements," NUREG-0737, November 1980.
5.
U.S. Nuclear Regulatory Commission, "NRC Action Plan Developed as a Result of the TMI-2 Accident" NUREG-0660, Volumes 1 and 2, May 1980 (Revised:
T.ugust 1980).
6.
Letter from Marvin Lewis, member of the public, to Richard Major, ACRS Staff, regarding the restart of the Three Mile Island Nuclear Station Unit 1, dated November 16, 1980.
7.
Letter from E3 Lehmann, GPU Service Corporation, to Richard Major, ACRS Staff, transmitting Testimony outlines - TMI-1 Restart Proceeding, dated October 29, 1980.
8, Letter from H. Dieckamp, President, General Public Utilities Corporation, to J. Ahearne, Chairman, U.S. Nuclear Regulatory Commission, regirding raquest that the Commission reconsider and modify its Orders of.luly 2, 1979 and August 9,1979 dealing with the restart of Three Mile Island Unit No.1, dated December 1,1980.
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