ML19323B109
| ML19323B109 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 05/01/1980 |
| From: | Peoples D COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8005090274 | |
| Download: ML19323B109 (3) | |
Text
_.
8 005090 2 N N Commonwealth Edison
) On3 First N;tional Plaza, Chiergo, lihnois C
C (j] Address Reply to: Post Othee Box 767 Chicago, linnois 60690 May 1, 1980 Mr. Harold R. Denton, Director Of fice of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
Zion Station Unit 2 Cycle 5 Reload NRC Docket No. 50-304
Dear Mr. Denton:
Zion Unit 2 is currently in its fourth cycle of operation with a refueling outage scheduled to commence on May 3, 1980.
Cycle 4 operation will be terminated within a cycle burnup range of 9000 to 10,500 MWD /MTU.
Startup for Cycle 5 is expected to occur in late June, 1980.
This letter is to advise you of Commonwealth Edison Company's review of and plans regarding the Zion Unit 2 Cycle 5 reload core.
The Zion Unit 2, Cycle 5 reload core was designed to perform under current nominal design parameters, Technical Specifications and related bases, and current setpoints such that:
1.
Core characteristics will be less limiting than those previously reviewed and accepted; or 2.
For those postulated incidents analyzed and reported in the Zion Final Safety Analysis Report (FSAR) which could potentially be affected by fuel reload, reanalysis has demonstrated that the results of the postulated events are within allowable limits.
Commonwealth Edison Company performed a detailed review at Westinghouse on the bases, including all the postulated incidents considered in the FSAR, of the Westinghouse Reload Safety Evaluation Report (RSER).
Based on this review and the Westin0 house RSER, safety evaluations were performed by Commonwealth Edison On-Site and Off-Site Review pursuant to the requirements of 10 CFR 50.59(a) and 10 CFR 50.59(b).
k h
Mr. Harold R. Denton, Director May 1, 1980 Page 2 The reload fuel mechanical and thermal-hyraulic design for the Cycle 5 reload core is unchanged from that of the previously reviewed and eccepted reload designs.
The current FN limit of H
less than 1.55 and penalties for rod bow ensure that the DNB ratio remains above 1.30.
In addition, based on the Westinghoue.e
" Eighteen Case" analyses, a total nuclear peaking f actor (Fg) of 2.13 could occur for the full range of power distributions, including load follow maneuvers (which are currently prohibited per the NRC ORDER of February 29, 1980), allowable under Constant Axial Offset Control (CAOC).
The re fo re, in order to accommodate the current Zion Station Fg peaking factor limit of 1.93, axial power distribution monitoring type surveillance will be utilized for power levels above 90.6% of rated power.
Should approval of the pending Fg peaking factor limit of 2.200 be received, this surveillance will not be required.
As in the past, the reload safety evaluation relied on previously reviewed and accepted analyses reported in the FSAR, fuel densification reports and previous reload safety evaluation reports.
A detailed review of the core characteristics was performed to determine those parameters affecting the postulated accident analyses reported in the Zion FSAR.
For those incidents whose consequences could potentially be affected by the reload core characteristics, the incidents were reanalyzed.
Commonwealth Edison verified that the reanalyses were performed in accordance with the Westinghouse reload safety evaluation methodology as outlined in the March 1978 Westinghouse topical report entitled " Westinghouse Reload Safety Evaluation Methodalogy" (WCAP-9272).
Commonwealth Edison also verified that the results of these reanalyses were within previously reviewed and accepted limits.
The reload safety evaluation demonstrated that Technical Specification changes are not required for operation of Zion Unit 2 during Cycle 5.
Commonwealth Edison On-Site and Of f-Site Review concluded that no unreviewed safety questions as defined by 10 CFR 50.59 are invovTed with this reload.
More specifically with this reload:
1.
There is no increase in the probability of occurence or l
the consequence of an incident or malfuncton of equipment important to safety previously evaluated in the safety analysis report; l
l
Mr. Harold R. Denton, Director May 1, 1980 Page 3 2.
No additional accident or malfunction of a dif ferent type than any evaluated prev!cusly in the safety analysis reported has been created; and 3.
There has been no reduction in the margin of safety as defined in the basis or any Zion Unit 2 technical specification.
Therefore, based on this review, application for amendment to the Zion Unit 2 operating license is not required.
Finally, verification of the reload core design will be performed per the standard startup physics tests normally performed at the start of each Zion reload cycle.
These tests will include but not be limited to:
1.
Control rod drive tests and drop time; 2.
Critical baron concentration measurements; 3.
Control rod bank worth measurements; 4.
Moderator temperature coefficient measurement; 5.
Power coefficient measurement; and 6.
Startup power distribution measurements using the incore flux mapping system.
Very truly yours,
.i. y O. L. Peoples Director of Nuclear Licensing cc:
Document Management Branch (NRC) 3510A l
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