ML20091E079
| ML20091E079 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood  |
| Issue date: | 04/06/1992 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20091E068 | List: |
| References | |
| NUDOCS 9204130330 | |
| Download: ML20091E079 (3) | |
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UNITED STATES
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NUCLE AR REGULATORY COMMISSION
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e SAFETY EVAllLATION BY THE OFFICE OF N1!j; LEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 45 TO FACllITY OPERATING LICENSE NO. NP.E-32 AND AMENDMENT NO. 34 TO FACILITY OPE &BTING LlifNSE NO. NPF-72
[0MMONWEALTH EDISON COMPANY BYRON STATIDN. UNIT NO. 1 BRAIDWOOD STATION. UNIT N0 _1 1
DOCKET NQS. STN 50-454 AND STN 50-456
1.0 INTRODUCTION
In 'a submittal dated October 26, 1990, as supplemented April 23, 1991, November 18, 1991, and February 6, 1992, the Commonwealth Edison Company (Ceco) described proposed changes to the low-low steam generator (SG) level reactcr trip / auxiliary feedwater initiation setpoints for the Unit 1 Model D-4 steam generators.
These setpoints are contained in Technical Specification (TS) Tables 2.2-1 and 3.3-4, Reactor Trip System Instrumentation Trip Setpoints and Engineered Safety Features Actuation System Instrumentation Trip Setpoints, respectively. These proposed changes resulted from a reassessment of the setpoints using an updated setpoint methodology and will allow operation of the Unit I steam generators over a greater range during operational transients.
The February 6, 1992, submittal provided additional clarifying information that did not change the initial proposed no significant hazards consideration deters.ination.
The submittals also addressed the impact of the changes on the Updated Final Safety Analysis Report (UFSAR) Chapter 15 analyses, and proposed TS changes to reflect the modifications.
2.0 STAFF EVALUATION 2.1 Setpoint Changes The Byron and Braidwood TSs express tha SG low-low water level trips in terms of percent of narrow range water level instrument span (NRS). The SG recirculation flow velocity head is included in the consideration of revised setpoints. Velocity head effects result in indicated levels for any given power less than or equal to the actual level, with the amount of discrepancy varying directly but not proportionally with power.
The low-low SG level trip setpoints for the proposed Byron and Braidwood No.1 Units TS changes account for the above considerations, and are based on consistency with safety analysis assumptions and with the setpoint methodology described in the Westinghouse Topical Reports WCAP-12583 and WCAP-12523.
92o4130330 920406 DR ADOCK 0500 4
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This methodology, incorporating the above considerations, has been used in previous Byron and Braidwood applications and was approved by the staff.
Since the basic methodology has not been changed for this use, we also find it applicable to Byron and Biaidwood Units 1 for the current setpoints determination.
2.2 Chapter 15 Analyses 2.2.1 Non-LOCA Event Analyses The submittals provided an assesssment of the impact of the changes on UFSAR Chapter 15 analyses and on Anticipated Transients Without Scram (ATWS) considerations.
For Chapter 15 events and ATWS considerations, the licensee found that the calculated results for existing Byron and Braidwood analyses, performed assuming Model D-4 SGs, would be unaffected by the modified trip settings. The staff finds this acceptable.
2.2.2 LOCA Analyses The licensee's submittals indicated that LOCA analyses were not adversely affected by the changes because analysis assumptions were not changed. We find this acceptable.
3.0 TECHNICAL SPECIFICATION CHANGES The licensee's submittal proposed changes to two TS pages to be implemented in the operating cycle after SG modification for each unit (Byron Unit I and Braidwood Unit 1) to reflect the setpnint modifications discussed in Section 2.1 of this report. These are:
(a) TS page 2-5, Table 2.2-1, Item 13.a., SG Water Level Low-Low reactor 4
prote tion system (RPS) trip - values for total allowance (TA),
parameters not measured on a 3eriodic basis (Z), and sensor error (SE) are identified as not applica)1e (N.A.).
The new trip setpoint is 33.0%
of NRS and the new allowable value is 31.0% of HRS.
(b) TS page 3/4 3-26, Table 3.3-4, Item 6.c.1, SG Water Level-Low-Low-Start Auxiliary Feedwater Motor-Driven Pump and Diesel-Driven Pump - the new values are the same as in (a) above.
The licensee's submittals based their justification of these modified setpoints on consistency with UFSAR Chapter 15 analyses assumptions and ATWS considtrations, as discussed in Section 2.2 of this report.
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. We find the licensee's submittal, describing low-low SG 1evel trip setpoint-changes and analytical justifications acceptable based on use of a'setpoint methodology which had been previously used in an approved application, and on justifications citing applicable UFSAR analyses using approved methodologies.
4.0 STATE CONSULTATIQN f
In accordance with the-Commission's regulations, the Illinois State official was-notified of the proposed issuance of the amendments. The State official
- had 'no coments.
5.0- ENVIRONMENTAL CONSIDERATION The amendments change a requirement with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. The NRC staff has determined that the amendments involve no significant increase in the amounts, and no significant change in the types, of-any effluents-that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure, sThe Commission has previously issued a proposed finding that the amendments involve no significant hazards consideration, and there has been no public comment onssuch finding (57 FR 2588)..Accordingly, the amendments meet
- the eligibility criteria for categorical exclusion-set forth.in 10 CFR-
.51.22(c)(9).
Pursuant to 10-CFR 51.22(b), no environmental impart statement or environmental-assessment need be prepared in connection with the issuance-of the amendments.
6.0- CONCLUSION 1
The Commission ~has concluded, based on the considerations discussed above, that:- (1)--there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner,-(2) such-
- activities will be conducted in compliance with the Commission's-regulations, and-(3) the-issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
F. Orr L
Date:. March 25, 1992 L
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