ML20206B553
| ML20206B553 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood  |
| Issue date: | 04/23/1999 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20206B549 | List: |
| References | |
| NUDOCS 9904290288 | |
| Download: ML20206B553 (3) | |
Text
.U utz g
- 4 UNITED STATES g
j NUCLEAR REGULATORY COMMISSION o
WASHINGTON, D.C. 30086 4001
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.107 TO FACILITY OPERATING LICENSE NO. NPF-37.
AMENDMENT NO. 107 TO FACILITY OPERATING LICENSE NO. NPF-66, AMENDMENT NO.100 TO FACILITY OPERATING LICENSE NO. NPF-72.
AND AMENDMENT NO.100 TO FACILITY OPERATING LICENSE NO. NPF-77 COMMONWEALTH EDISON COMPANY BYRON STATION. UNIT NOS.1 AND 2 BRAIDWOOD STATION. UNIT NOS.1 AND 2 DOCKET NOS. STN 50-454. STN 50-455. STN 50-456 AND STN 50-457
1.0 INTRODUCTION
By letter dated December 29,1998, the Commonwealth Edison Company (Comed, or the licensee) requested changes to the Technical Specifications (TSs) for Byron Station, Units 1 and 2, and Braidwood Station, Units 1 and 2. The changes would revise the Allowable Values (AVs) for 12 functions of the Reactor Trip System (RTS) and Engineered Safety Features Actuation System (ESFAS).
2.0 EVALUATION The AVs are used as a basis for checking instrument channel operability when performing instrument loop calibrations. AVs account for uncertainty, calibration tolerances and instrument drift, which is assumed to occur between calibrations, to verify that the trip or actuation will occur within the limits assumed in the safety analyses. The use of AVs for determining instrument operability is based on industry standards and practices.
The licensee proposed to change the AVs for twelve RTS and ESFAS functions. The changes result from updated calculations that use revtied plant-specific parameters and reflect Comed's use of more accurate Measurement and Test Equipment (M&TE). The licensee proposed to change the following AVs:
Reactor Trip System Allowable Values (Table 3.3.1-1)
Function 2.a.
Power Range Neutron Flux High Function 2.b.
Power Range Neutron Flux Low Function 3.a.
Power Range Neutron Flux Rate High Positive Rate 9904290288 990423 PDR ADOCK 050004 4 P
,,5e l 4\\ Function 3.b.
Power Range Neutron Flux Rate High Negative Rate Function 4.
Intermediate Range Neutron Flux Function 6.
Overtemperature AT Function 7.
Overpower aT Function 8.a.
Pressurizer Pressure Low Function 15.a.
Turbine Trip, Emergency Trip Header Pressure Engineered Safety Feature Actuation System Allowable Values (Table 3.3.2-1)
Function 1.d.
Safety injection Pressurizer Pressure - Low Function 5.b.2 Turbine Trip and Feedwater Isolation Steam Generator Water Level -
{
High High (P-14) Unit 2 j
Function 8.c.
ESFAS Interlocks Tm - Low Low The revised AVs were determined in accordance with the Westinghouse methodology described in WCAP-12583, " Westinghouse Setpoint Methodology for Protection Systems, Byron /Braidwood Stations," dated May 1990, except for Tabfe 3.3.1-1, Function 15a, " Turbine Trip, Emergency Trip Header Pressure." The NRC has previously reviewed and approved the Westinghouse methodology for use at Braidwood and Byron Stations, as is documented in the Sefety Evaluation for License Amendment No. 42 for Braidwood and License Amendment No. 53 for Byron, dated April 13,1993. The methodology used to determlae the proposed AV for Table 3.3.1-1, Function 15a, " Turbine Trip, Emergency Trip Header Pressure," is consistent with the Instrument Society of Arnerica (ISA) standard, ISA-S67.04-1994, "Setpo!nts for Nuclear Safety-Related instrumentation Used in Nuclear Power Plants" and Regulatory Guide 1.105,
" Instrument Setpoints for Safety-Related Systems," Revision 2, dated February 1986. The staff has previously accepted this methodology for LaSalle County Station, Unit 1, as is documented in the safety evaluation for Amendment No.129 for LaSalle County Station, dated July 6,1998.
Based on this, the staff finds the use of this methodology at Braidwood and Byron to be acceptable.
The licensee stated that no changes were made to the trip setpoints or the analytical limits used in the safety analyses. The only changes were to the AVs used as the basis for determining instrument channel operability, which have been derived from the analytical limits. In all cases, the difference betweer' the trip setpoints and the AVs has been reduced, which increases the margin with respect to the analyzed cafety limits.
The licensee used acceptable methodologies and updated, plant-specific input parameters, including M&TE, to determine the proposed AVs. Based on the above, the staff finds the proposed changes 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.
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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 Commission has previously issued a proposed finding that the amendments involve no j
significant hazards consideration, and there has been no public comment on such finding (64 FR 9186). 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 impact statement or environmental assessment need be prepared in connection with the issuance of the amendments.
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 Stewart Bailey Date: April 23, 1999 l
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