ML20207E889
| ML20207E889 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood  |
| Issue date: | 06/02/1999 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20207E887 | List: |
| References | |
| NUDOCS 9906070193 | |
| Download: ML20207E889 (3) | |
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UNITED STATES u
j NUCLEAR REGULATORY COMMISSION j
i WASHINGTON, D.C. 90006 4 001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.109 TO FACILITY OPERATING LICENSE NO. NPF-37.
AMENDMENT NO.109 TO FACILITY OPERATING LICENSE NO. NPF-86.
AMENDMENT NO.' 102 TO FACILITY OPER/ TING LICENSE NO. NPF-72.
AND AMENDMENT NO.102 TO FACILITY OPERATINfi. LICENSE NO. NPF-77 COMMONWEALTH EDISON COMPANY BYRON STATION. UNIT NO'.1 AND 2 d
BRAIDWOOD STATION. UNIT NOS.1 ANQ2 DOCKET NOS. STN 50-454. STN 50-455. STN 50-456 AND STN 50-457
1.0 INTRODUCTION
I By letter dated March 22,1999, Commonwealth Edison Company (Comed, the licensee) requested Technical Specification (TS) changes to permit the use of the Gamma-Metrics Post Accident Neutron Monitors (PANMs) source range neutron flux detectors in addition to the Westinghouse source range neutron flux monitors to satisfy the TS 3.9.3 Limiting Condition for Operation (LCO) which requires two source range neutron flux monitors be operable during Mode 6 operations (refueling). Specifically, the proposed change would modify TS 3.9.3,
" REFUELING OPERATIONS, Nuclear Instrumentation," to insert the word " required" into Conditions A. and B. Condition A would now state: "One required source range neutron flux monitor inoperable." Condition B would now state: "Two required source range neutron flux monitors inoperable."
NUREG-1431, Revision 1, " Standard Technical Specifications Westinghouse Plants," dated April 1995, included use of the word " required" as an option for plants with more than the TS required minimum number of source range neutron flux monitors.
2.0 EVALUATION During refueling (Mode 6), two operable source range monitors are required to provide redundancy during fuel movement or other actions that may cause positive reactivity @anges, including rernoval of upper internal components. The proposed change would permk ce use of either the Gamma-Metrics PANM or the Westinghouse Boron Trifluoride (BF ) Proportional 3
Counter ncutron flux monitors.
The Gamma-Metrics PANM source range monitor is an enriched U-253 fission chamber detector which has a sensitivity of four cps / neutron-volts (eps/ny) for thermal neutrons and a 9906070193 990602 PDR ADOCK 05000454 P
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- sensitivity of two cps /nv for fast neutrons. The Westinghouse (BF ) source range monitor, on 3
the other hand, has a sensitivity of 13 cps /nv. The Gamma-Metrics PANM source range monitor has a comparable range and accuracy (1 E-1 to 1 E+5 cps with an accuracy of 2 percent of full scale) to that of the Westinghouse (BF ) source range monitor (1 E O cps to 3
1 E+6 cps with an accuracy of 3 percent of full scale). Although the Gamma-Metrics PANM source range neutron flux monitors do not have the ability to provide audible count rate indication, the current TS do not require audible count rate indication in the containment and the control room during operational Mode 6.' Both monitors satisfy the TS Bases background information of six decades of indication. Each portion of the Westinghouse source range neutron flux monitors has two trains, each is assigned to an independent engineered
- safeguards features (ESF) division. These trains are physically and electrically separated in 4
accordance with applicable IEEE Standards. Each portion of the Gamma-Metrics PANM instrumentation has two trains, each assigned to an ESF division. These trains are physically
- and electrically separated in accordance with applicable IEEE Standards.' The Westinghouse and Gamma-Metrice PANM source range neutron flux monitors are functionally equivalent and both are Safety Category I (Class 1E) systems. Based on the above, the proposed change will maintain two BF SR monitors for visually monitoring core reactivity as currently discussed in 3
the Bases for the affected TS.
The licensee did not propose.any changes to the current TS Required Action (s), Completion.
Time (s), Surveillance (s), or Surveillance Frequency (ies). As such, the licensee will be required
- to perform applicable sunreillances to ensure that the Gamma-Metrics PANM source range neutron flux monitors meet the same operability requirements as the Westinghouse source range neutron flux monitors.
Although both the Westinghouse and Gamma-Metrics PANM source range neutron flux monitors provide visual indication in the control room, this proposed change to the TS would result in a reduction in the alarming capabilities since the PANM source w.nge monitor does not have this capability. However, there are no specific requirements to have or maintain operability of alarming capability.' The primary safety function of the source ange monitors while shut down is to notify the operators of, and initiate compensatory actions for, inadvertent boron dilution. However, dilution during Refueling Mode has beEn precluded through administrative control of the. valves in the possible dilution flow paths. Therefore, this loss of redundancy is not considered to result in significant safety concems.
Based on the above, the staff considers the proposed changes to TSs to be acceptable.
3.0 STATE CONSULTATION
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 comments.
4.0 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. - The i
Commission has previously issued a proposed finding that the amendments involve no significant hazards consideration, and there has been no public comment on'such finding (64 FR 14944). Accordingly, the amendments meet the eligibility criteria for categorical exc!usion set forth in 10 CFR 51.22(c)(9). ' Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendments.
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5.0 CONCLUSION
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: John B. Hickman Date: June 2,1999 1
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