ML20024D061

Addresses Cycle 8 Reload SER Concerns Re Fuel Assembly Seismic Analysis,Worst Case ECCS Assumptions & High Burnup Fuel.Schedule for Submittals Re Cycle 9 Reload Also Provided

ML20024D061
Person / Time
Site:	Fort Calhoun
Issue date:	07/28/1983
From:	William Jones OMAHA PUBLIC POWER DISTRICT
To:	Clark R Office of Nuclear Reactor Regulation
References
LIC-83-184, NUDOCS 8308030100
Download: ML20024D061 (3)

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Omaha Public Power District i 1623 Harney Omaha, Nebraska 68102 402/536-4000 July 28, 1983 LIC-83-184 Mr. Robert A. Clark, Chief U. S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation i

Division of Licensing l

Operating Reactors Branch No. 3 Washington, D.C. 20555

Reference:

Docket No. 50-285

Dear Mr. Clark:

Response to Concerns Contained in the Cycle 8 Reload SER and Cycle 9 Reload Schedule The Cycle 8 reload SER request.ed the District address concerns related to fuel assembly seismic analysis, worst case ECCS assumptions, high burnup fuel, and documentation of the District's reload methodology. This letter addresses these concerns and also provides a schedule for submittals re-lated to the Cycle 9 reload.

Fuel Assembly Seismic Analysis The District has reviewed the seismic analysis contained in Appendix F of the USAR to determine the type of analysis performed for the first core.

This type of analysis would be performed on a core containing CE and ENC l or ENC fuel, since it is the licensing basis for core seismic analysis.

Based on the information contained in Appendix F, the District concludes that a dynamic seismic analysis was not performed for the fuel assemblies.

It is the District's position that an analysis to show that compliance with the fuel assembly structural criteria in Appendix A of SRP-4.2 for the design seismic event is outside the scope of design basis for the Fort Calhoun Station Unit No. 1 and that an unreviewed safety question does not exist for a core of CE and ENC fuel or ENC fuel with respect to the design seismic event. Therefore, it is the District's position that such an l

analysis is not required.

Worst Case ECCS Assumptions t

1 The SER required that the assumption of a worst single failure in the ECCS be reviewed and verified as more limiting than an assurption of no single failure. In response to the District's request, Exxon Nuclear Company has performed a sensitivity study of the Fort Calhoun Cycle 8 ECCS analysis to determine which assumption provided the most restrictive results.

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,Mr. Robert A. Clark LIC-83-184 Page Two.

1 The worst single failure assumption was the loss.of a low pressure safety

. injection pump. When the ECCS analysis was redone, due to the Fort.

Calhoun ECCS configuration, the estimated full safety-injection flow re-sulted-in a higher reflood rate with no significant effect on containment pressure. Assuming the single failure, the analysis predicted lower re-flood rates and a higher peak cladding temperature. .Therefore, the Fort Calhoun Cycle 8 ECCS analysis provides the most limiting prediction with the assumption of a single. failure.

l High Burnup Fuel 4

The Cycle 8 reload SER stated that batch average burnups exceeding 38,000 MWD /MTU in future cycles.would involve an unreviewed safety question re- -

lated to radiological consequences. Based on a May 16, 1983 telephone conversation between the Commission and District staffs, it is.our under-standing that these high burnup concerns will be addressed.in the extended burnup topicals submitted by the nuclear fuel vendors. In response to i .your request made during the May 16, 1983 telephone conversation, the anticipated discharge batch burnups for future cycles are provided in

. Table 1.

TABLE 1 FORT CALH0UN STATION UNIT NO. 1

. ANTICIPATED BATCH DISCHARGE BURNUP *

(All fuel manufactured by ENC)

Anticipated Batch Average Cycle Shutdown Cycle No. of Discharge Burnup Discharged Date Loaded Assemblies (MWD /MTU) 1 9- Sept 1985 6 24 34,000 9 Sept 1985 7 19 35,500 10 Mar 1987 7 17 40,000 10 Mar .1987 8 23 36,000

- 11 Sept 1988 8 5 39,000 11 Sept 1988 9 8 44,000 4 11 Sept 1988 9 31 39,500 Documentation of Reload Methodoloqy

'The Cycle 8 reload SER requested the District submit methodology reports

- well-in advance of the Cycle 9 reload application date. The scope of these methodology reports was discussed in a May 11, 1983 telephone con-i versation between members of the Commission and District staffs. Based on requests made by members of the Commission staff during these conver-

. sations, the District will submit methodology reports on reactor physics and transient analyses. In addition, the District intends to submit a reload methodology report which will provide an overview of the analyses performed during a reload core analysis and the interfaces between these

. analyses.

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Mr. Robert A. Clark LIC-83-184 Page Three

.The District also intends to utilize a Statistical Combination of Uncer-tainties'(SCU) in the Cycle 9 reload analysis. The SCU analysis is being performed by Combustion Engineering utilizing the methodology previously submitted and approved on the Calvert Cliffs and St. Lucie 1 dockets. The schedule for submittals and events related to Cycle 9 reload licensing is given in Table 2.

TABLE 2 CYCLE 9 RELOAD SCHEDULE Event Date Submit Reactor Physics and Transient September 23, 1983 Analysis Methodology Reports Submit Statistical Combination of Uncer- October 21, 1983 tainties Report Submit Cycle 9 Technical Specifications February 10, 1984 Start of Refueling March 19, 1984 Cycle 9 Startup May 14,1984 The District believes this letter addresses all Commission staff concerns discussed in the Cycle 8 reload SER. The submittal of the methodology re-ports will satisfy all requirements discussed in the SER.

Sincerely, e

r, Cb Division / Manager Production Operations WCJ/JKG:jmm cc: LeBoeuf, Lamb, Leiby & MacRae 1333 New Hampshire Avenue, N.W.

Washington, D.C. 20036

, Mr. L. A. Yandell, Senior Resident Inspector

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