ML20080M448
| ML20080M448 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 02/10/1984 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20080M446 | List: |
| References | |
| NUDOCS 8402170526 | |
| Download: ML20080M448 (2) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION o
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENTS NOS. 91 AND 93 TO FACILITY CPERATING LICENSES NOS. DPR-44 AND DPR-56 PHILADELPHIA ELECTRIC COMPANY PUBLIC SERVICE ELECTRIC AND GAS COMPANY DELMARVA POWER AND LIGHT COMPANY ATLANTIC CITY ELECTRIC COMPANY PEACH BOTTOM ATOMIC POWER STATION, UNITS 2 AND 3 DOCKETS NOS. 50-277 AND 50-278 INTRODUCTION By letter dated May 26, 1982, the Philadelphia Electric Company (the licensee) requested that the Technical Specifications 'for Peach Bottom Atomic Power Station, Units 2 and 3, be changed to provide an increase in the minimum number of required operable instrument channels for the Average Power Range Monitor (APRM) Rod Block Trip System from two to four and the Intermediate Range Monitor (IRM) Rod Block Trip System from three to six. The changes would also add a new " Action" statement (Table 3.2.C) to correspond to changes in the required number of operable channels. These changes involve specific control rod withdrawal blocks which are intended to inhibit control rod with-drawals when an unsafe condition is being approached by a specific monitored parameter.
EVALUATION The licensee requested the increase in the minimum number of required operable instrument channels for the APRM and IRM Rod Block. Trip Systems in response to a concern raised by the NRC staff and conveyed to the licensee by the NRC Project Manager (" Misinterpretation of Number of Operable Instrument Channels for APRM Control Rod Withdrawal Block", December 29, 1981, T. Novak, NRC, to NRC Project Managers).
It was indicated to the licensee that there had been misinterpretations of the Technical Specifications regarding the minimum number of APRM operable channels required for this specific control rod block function. The APRM rod withdrawal block function for the Peach Bottom facilities is divided into two circuits of three channels each. Any one of the six APkM channel inputs will result in the actuation of the rod withdrawal bl ock. As presently written, the Peach Bottom Technical Specifications state that two out of three channels are required for each of the two trip circuit systems to accomplish the rod block action. However, this is not 8402170526 840210 PDR ADOCK 05000277 p
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. the intent of this Technical Specification because only one APRM signal input is needed to initiate a rod withdrawal block (memo from T. Novak to ORPMs, December 29,1901).
Furthermore, it is the NRC staff's position that Technical Specifications should permit any two of the six APRM channels to be bypassed for the rod withdrawal block function. The proposed amendment would require that the minimum number of operable channels for the APRM Rod Block Trip System (Table 3.2.C) be four. This change, including the proposed " Action" statement, is responsive to the staff's concern expressed to the licensee as well as being fully consistent with the Standard Technical Specifications for Boiling Water Reactors (NUREG-0123, Rev. 3).
In a similar manner, the Peach Bottom IRM Rod Block Trip System is also actuated by any single IRM instrument channel trip. There are four channels per trip system for a total of eight instrument channels. For the IRM Rod Block Trip System, the proposed amendments would reqeire six operable channels out of the eight available. This change and the accompanying " Action" statement are fully consistent with the Standard Technical Specifications for Boiling Water Reactors covering the minimum number of operable channels per trip function for IRM Rod Withdrawal Block Instrumentation.
We, therefore, conclude that the proposed chances in the minimum number of operable channels for the APRM and IRM Rod Withdrawal Block Trip Systems are acceptabic.
ENVIRONMENTAL CONSIDERATION We have determined that the amendments do not authorize a change in effluent types or total amounts nor an increase in power level and will not result in any significant environmental impact. Having made this determination, we have further concluded that the amendments inv.olve an action which is insignificant from the standpoint of environmental impact and, pursuant to 10 CFR [51.5(d)(4), that an environmental impact state-ment, or negative declaration and environmental impact appraisal need not be prepared in connection with the issuance of these amendments.
CONCLUSION We have 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 mannar, and (2) such activities will be conducted in compliance with the Commission's regulations and the issuance of tLese amendments will not be inimical to the common defense and security or to the health and safety of the pubiic.
Dated: February 10, 1984 The following NRC personnel have contributed to this Safety Evaluation:
G. Gears, B. Siegel.
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