ML20008E732
| ML20008E732 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 02/27/1981 |
| From: | William Jones OMAHA PUBLIC POWER DISTRICT |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20008E733 | List: |
| References | |
| TASK-1.C.6, TASK-2.B.2, TASK-2.F.2, TASK-TM NUDOCS 8103090540 | |
| Download: ML20008E732 (5) | |
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Omaha Public Power District 1623 MARNEY s OMAMA, NE5RASMA 68102
- TELEPHONE 536 4000 ARE A CODE 402 February 27, 1981 N
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Mr. Darrell G. Eisenhet, Director 7
U. S. Nuclear Regulatory Comission gN kpr 4
Office of Nuclear Reactor Regulation
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Director of Licensing i -i 0
Washington, D.C.
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Reference:
Docket No. 50-285 A
Dear Mr. Eisenhut:
In a telephone discussion between f%ssrs. Morris and Patterson of Omaha Public Power District and Mr. Wagner of the Commission, the need for additional information on schedules or programs related to three TMI Action Plan tasks was identified.
Those tasks are:
I.C.6 - verifi-cation of correct performance of operating activities, II.B.2 - plant shielding, and II.F.2 - instrumentation for detection of inadequate core cooling. The attached information (Enclosures 1, 2, and 3) provides the requested information and supplements the District's letters dated December 12, 1980, and December 31, 1980.
Sincerely,
,y
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W. C. Jones Division Manager Production Operations WCJ/KJM/TLP:jmm Attachment cc: LeBoeuf, Lamb, Leiby & MacRae 1333 New Hampshire Avenue, N.W.
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Task I.C.6 Procedures to Verify Correct. Performance l
of Operating Activities j
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NUREG-0660 and clarification provided in NUREG-0737 require all I
licensees to review and/or revise procedures as necessary to ensure that i
an effective system of verifying correct performance of operating acti-vities is provided. The District has completed a review of the Fort i
Calhoun Station procedures. We believe the existing procedures provide assurance of correct performance of operating activities. A summary of the program in use at the Fort Calhoun Station is provided below.
The Fort Calhoun Station procedures presently require double verification of the proper line-up 3afety-related systems prior to plant l
l startup, as required by the nature of the outage.
The second verifi-l
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cation is performed by an individual who has been specifically qualified on the system being verified; e.g., en auxiliary operator who has been signed off on his system qualification book for the given system. These i
measures ensure that all safety-related systems are properly aligned for operation following a long term maintenance outage.
l Additionally, for maintenance of safety-related systems, prior to e
taking equipment out of service the redundant train is demonstrated to be operable. On completion of maintenance, the repaired / tested equip-l ment is tested to ensure proper operation.
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The District believes the program described above meets the re-i quirements for proper verification of operating activities, as defined l
1 in NUREG-0737.
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i Task 11.B.2 l
Modifications to Plant Shielding 4
NUREG-0737, Task II.B.2, requires all licensees to have available for review the final design details of all proposed shield modifications j
for spaces and systems that may be used for post-accident operations.
Final design information is ccmplete and available for review by the Commission.
In fact, the contract for wall construction had been re-leased for public bid and was then withdrawn when NUREG-0737 was issued.
4 Construction was expected to be completed by December 30, 1980.
The criteria used for design of the shielding m]difications was provided by NUREG-0578. NUREG-0660 and NUREG-0737 significantly relaxed the design criteria by eliminating the need to include noble gases as a source term in recirculating systems outside containment. Therefore, 4
the existing shielding design is conservative in relationship to the present design criteria. The District is presently evaluating the new criteria to determine whether ordinary concrete can be used in place of the high density concrete specified in the existing design. Use of ordinary concrete would significantly reduce the structural loading on existing walls and floors.
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The requirement of Task II.B.2 to have the final shielding design details available for review has been met by the District. We have a complete final design that bounds the criteria of NUREG-0737. Also, the j
shielding modifications will be completed by the required due date of January 1,1982; therefore, the District expects to meet the require-ments of this task in all respects.
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Task II.F.2 Instrumentation to Detect Inadequate Core Cooling The attached report provides the details of Omaha Public Power District's program to upgrade existing and add new instrumentation in order to provide an unambiguous indication of inadequate core cooling.
The report provides a description of the system's function, design requirements, procedures to be used with the equipment, and the analysis used to develop the procedures. A schedule for installing the equipment is dependent upon the teting results demonstrating the system's oper-ability.
Since early 1980, the C-E Owners Group has conducted an evaluation of response characteristics of instrumentation under conditions of inadequate core cooling. An outline of this evaluation was discussed with the Nuclear Regulatory Comission staff at a meeting in Bethesda,_
Maryland on May 28, 1980. The instruments whose response characteristics have been evaluated are the subcooled margin monitor, the heated junc-tion thermocouple system, core exit thermocouples, in-core thermocouples, self-powered neutron detectors, hot leg resistance temperature detectors, and ex-core neutron detectors. This evaluation was completed in December, 1980, and a preliminary draft of these results has been distributed to members of the C-E Owners Group. Omaha Public Power District is cur-i rently studying these results.
Omaha Public Power District has participated over the past year in the C-E Owners Group development of a technique for measurement of water level in the reactor vessel. The technique which has been selected by the C-E Owners Group is use of heated junction thermocouples (HJTC) distributed at various radial and axial locations in the reactor vessel above the fuel alignment plate. The design objective of this system is to provide a measurement of the water inventory in the reactor vessel above the fuel alignment plate. The details of this design activity were discussed with the Nuclear Regulatory Commission staff at a meeting in Bethesda, Maryland on May 28, 1980.
Since thr? tire, Combustion Engineering has issued a commercial proposal fr W MTC system. Omaha Public Power District is evaluating the HJTC A t e at a possible com-ponent of an instrumentation system for mr n c 1a, inadequate core j.
Cooling.
Attached is a Sumary Status Report on C-E Owners Group inadequate core cooling activities which includes a conceptual design description
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of an Inadequate Core Cooling (ICC) Detection System. Omaha Public Power District feels that this design requires further evaluation and development before the District can make a commitment to its use ir, the Fort Calhoun Station. Such evaluations, including the testing progrc for the HJTC system outlined in the attached report, are being conducted 2
l by the C-E Owners Group. Omaha Public Power District is a participating member.
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Omaha Public Power District is participating as a member of the C-E Owners Group to define appropriate generic and plant-specific document-ation of the ICC Detection System.
It is expected that this definition will be completed during the first quarter of 1981.
Following com-pletion of this C-E Owners Group effort, Omaha Public Power District will develop a plant-specific definition and schedule for further ICC j
Detection System documentation.
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