ML19274E803

Forwards Addl Info to 790313 Request Re Nb Power District'S 790131 Reload License Application

ML19274E803
Person / Time
Site:	Cooper
Issue date:	04/16/1979
From:	Pilant J NEBRASKA PUBLIC POWER DISTRICT
To:	Ippolito T Office of Nuclear Reactor Regulation
References
NUDOCS 7904240456
Download: ML19274E803 (4)

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GENER AL OFFICE

' h) P. o BO X 499, COLUMBUS, NE B R ASKA 68601 33 Nebraska Public aw== Power D --==c==----------=-----------------------

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1<<< mo~ e <402, se.. sei April 16, 1979 Director, Nuclear Reactor Regulation Attention: Mr. Thomas A. Ippolito, Chief Operating Reactors Branch No. 3 Division of Operating Reactors U.S. Nuclear Regulatory Commission Washington, DC 20555

Subject:

Reload 4, Cycle 5 - Startup Physics Testing Cooper Nuclear Station NRC Docket No. 50-298, DPR-46

Dear Mr. Ippolito:

Your letter of March 13, 1979 transmitted a request for additional infor-mation relating to Nebraska Public Power District's January 31, 1979 Reload License application. The District's response to this request for information was transmitted Fbrch 22, 1979, and included as Attachment 2 the Startup Physics Test Program for Cooper Nuclear Station. Subsequent to that transmittal, a Startup Physics Test meeting was held March 29, 1979 with the Reactor Safety Branch of the Division of Operating Reactors.

At this meeting the utilities presented a comprehensive Startup Physics Test Program which meets the Staf f's objective of verifying that the core conforms to design. Based on this meeting with the Staff, attached please find a revised description of the startup physics testing to be performed at Cooper Nuclear Station following Reload 4 and subsequent refuelings.

If you have any questions or require clarification on any of the enclosed tests, please contact me.

Sincerely, M

., A. Pilant Director of Licensing and Ouality Assurance JDW/cmk

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Attachment

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790424095%

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l. CORE LOADING VERIFICATION

1. PURPOSE The purpose of this test is to visually verify that the core is loaded as intended.

II. DESCRIPTION An underwater television camera or suitable viewing device will be eniployed to verify both proper orientation and location of each fuel assembly in the reactor core. At least one independent person must also either participate in performing the verification or review a videotape of the verification prior to startup.

III. CRITERIA AND ACTIONS The as-loaded core must conform with the referenced core upon which the licensing analysis was performed. Any discrepancies discovered in the loading will be promptly corrected and the affected areas re-verified to be properly loaded prior to startup.

Conformance to the reference loading will be demonstrated by a permanent core serial number map, and documented by the signatures of the verifiers.

2. CONTROL ROD OPERABILITY AND SUBCRITICALITY CHECK I. PURPOSE This test is performed to assure that no gross local reactivity irregularities exist and that all operable control rods are functioning properly.

II. DESCRIPTION The control rod mobility test will be performed after the four bundles surrounding the given control rod are loaded. The subcriticality check will be performed after the core loading has been completed.

Performance of this test will provide assurance that criticality will not occur due to the withdrawal of a single rod. Each control rod in the core will be withdrawn and inserted one at a time to assure its mobility with drive pressure. Also, the nuclear instrumentation will be monitored during the movement of each control rod to verify sub-criticality.

III. CRITERIA AND A_CTIONS For those control rods that will not move under drive pressure, appropriate repairs or adjustments will be made so that the drive pressure criteria can be met or the rod will be declared inoperable as described in the technical specifications. If criticality were to be achieved by the withdrawal of a single control rod, the control rod would be inserted and all further rod movements would cease and an investigation would be conducted to determine the cause.

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3. TIP SIGNAL UNCLRTAIN'lY TEST I. PURPOSE The purpose of this test is to determine the Traversing In-Core Probe (TIP) system total uncertainty using a statistical analysis.

II. DESCRIPTION Total TIP signal uncertainty consists of geometric and random noise components. Data to perform the analysis is obtained at inte rmed iate power levels and/or power levels greater than 75% with the reactor operating at steady state in an octant symmetric rod pattern (if possible).

This, data will be additionally used to perform a gross TIP symmetry check, which is a comparison of integrated readings from symmetrically located TIP's.

III. CRITERIA AND ACTIONS A. The total TIP signal uncertainty (random noise plus geometric uncertaintica) obtained by averaging these uncertainties for all data sets should be less than 9%. A minimum of two or up to six data sets may be used to meet the above criterion. If the 9% criterion is not met and the calculations have been rechecked, the calibration of TIP system (e.g. axial alignment) shall be checked. It may be necessary to omit data pairs from the analysis if exact octant symmetry is not attainable in fuel loading or control rod patterns. In such cases, offline code predictions of exposure or control rod induced asymmetry may prove useful in explaining the uncertainty.

B. The gross check of TIP signal symmetry should yield a maximum deviation between symmetrically located pairs of less than 25%. If the criterion cannot be met, the cause of the asymmetry must he investigated and an explanation attempted as per Criterion A.