ML19305B794
| ML19305B794 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 03/17/1980 |
| From: | Herbein J METROPOLITAN EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| TLL-117, NUDOCS 8003200395 | |
| Download: ML19305B794 (4) | |
Text
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Metropolitan Edison Company Post Office Box 480
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Middletown. Pennsylvania 17057 717 9444041 Writer's Direct C ai Nurnber March 17, 1980 TLL 117 Office of Nuclear Reactor Regulation Attn:
Mr. Harold R. Denton, Director U. S. Nuclear Regulatory Con ission Washington, D.C.
20555
Dear Sir:
Three Mile Island Nuclear Station, Unit I (TMI-1)
Operating License No. DPR-50 Docket No. 50-289 Response to NRC Letter Concerning the February 26, 1980 Incident at Crystal River Unit No. 3 Enclosed please find the responses to items 6 and 7 of your letter of March 6, 1980 to all operating B & W reactor licensees concerning the February 26, 1980 incident at Crystal River.
These responses are preliminary in nature and may be revised as a result af continued evaluation and better understanding of the Crystal River event.
Sincerely,/
y
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J. G. Herbein Vice President Nuclear Operations JGH:CFM: hah Attachments cc:
J. T. Collins kOO(
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METROPOLITAN EDISON COMPAW JERSEY CENTRAL POWER AND LIGHT COMPA.W AND PENNSYLVANIA ELECTRIC COMPANY THREE MILE ISLAND NUCLEAR STATION, UNIT I Operating License No. DPR-50 Docket No. 50-289 This letter is submitted in support of the Nuclear Regulatory Commission request concerning the February 26, 1980 incident which occurred at the Crystal River Unit No. 3 Nuclear Station.
The responses to items 6 and 7 of the NRC's letter of March 6, 1980 are attached.
- Further, all statements contained in these responses have been reviewed and all such statements made and matters set forth therein are true and correct to the best of my knowledge, information and belief.
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METROPOLITAN EDISON COMPANY By/
y
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Vice President Sworn and subscribed to me this 17th day of March, 1980.
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TLL-117 ITEM 6.
Address each CR-3 proposed corrective action in terms of applicability to your plant.
RESPONSE
6.
CR-3 Planned Corrective Actions, as given in Enclosure 2 of NRC letter dated March 6,1980, are being addressed as follows:
IMMEDIATE CR-3 CORRECTIVE MEASURES:
(1) Thorough testing of the NNI system to determine the cause of f ailure is Crystal River specific, and no action is being taken at TMI-1.
(2) The ICS/NNI design for TMI-1 is such that the PORV will not open on loss of power to ICS/NNI of loss of power internal to the ICS/NNI.
(3) The ICS/NNI design for TMI-1 is such that the pressurizer spray valve will fail as is and is normally closed on loss of any of the power feeds to or within the ICS/NNI.
(4) Positive indication of the PORV and Reactor Coolant System Safety Valves is being provided as described in the TMI-1 Restart Report, Section 2.1.1.2, and will be implemented before restart.
(5) Procedural control of the ICS/NNI instrument switches will be impl e-mented to minimize the number of instrument losses due to any partial powe r los s. This will be accomplished by preselecting instrument switchpositions for normal conditions.
(6) The TMI-l operators will be trained to respond to ICS/ NNI power failures as described in Response to Item 2 of TLL-114 dated March 13, 1980.
(7) The TMI-1 ICS/NNI is supplied from a 120 VAC vital bus as described in Response to Item 2 of TLL-114 dated March 13, 1980.
(8) TMI-1 does not have the type of events recorder used at Crystal Rive r.
TMI-1 relies rather on the originally supplied plant computer, plus a new "Modcomp" computer. These computers will be used contin-uously, and upon breakdown, corrective maintenance will be performed.
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(9) A s tudy is underway to determine the best means of providing indi-cation redundancy for certain essential plant parameters and to determine which parameters are essential (See Response to Item 2 of TLL-114).
c TLL-117 AT NEXT REFUELING CR-3 CORRECTIVE MEASURES:
(1) Suitable indication will be provided at TMI-1 to allow the operator to determine which ICS/NNI power supply has been lost such that appropriate corrective action can be taken.
(2) A review of fuse locations will be conducted to determine if faster access to essential ICS/NNI fuses at IMI-I is needed.
(3) Automatic start of the TMI-1 Emergency Feedwater (EFW) pumps is independent of the ICS/NNI.
IDNG-TERM CR-3 CORRECTIVE MEASURES:
(1) As described in our response to IE Bulletin 79-27, f urther review of the electrical distribution system for the ICS/NNI is being conducted to determine whether the reliability of the power supplies can be improved and to determine the best method of providing essential instrument redundancy (See response to IMMEDIATE (2) and (9) above).
(2) As part of the TMI-1 fire protection upgrading, a remote shutdown panel is being installed. This effort is currently scheduled for 4
completion by May 31, 1981.
(3) See response to LONG-TERM (1) above.
ITEM 7.
Expand your review under IE Bulletin 79-27 to include the implications of the CR-3 event.
Inform us of your schedule for completion of this expanded review as discussed on March 4,1980.
RESPONSE
7.
Our review of IE Bulletin 79-27 has been expanded as discussed in response to Items 2 and 6 of our March 13 letter (TLL-114) and is scheduled for ccmpletion by September 30, 1980 or as otherwise indicated above.
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