05000352/FIN-2009006-02
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Finding | |
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| Title | TS Requirements for MOV Thermal Overload Bypass Feature |
| Description | An unresolved item (URI) was identified because additional NRC review and evaluation is needed to determine if Exelon is meeting Technical Specification (TS)3.8.4.2b. and/or TS Surveillance Requirement (SR) 4.8.4.2.2. The team questioned whether Exelon was meeting the licensing requirements for bypassing thermal overloads for all Class 1E MOV\'s with spring-to-normal control switches during an accident and/or whether testing used to satisfy the requirements for a Channel Function Test of the MOV circuit was adequate related to alarm testing. TS Section 3.8.4.2b states that the thermal overload protection of all Class1E MOVs shall be bypassed under accident conditions for all valves with spring-to normal control switches. The team referenced Regulatory Guide (RG) 1.106, Thermal Overload Protection for Electric Motors on Motor-Operated Valves, which describes acceptable methods to ensure that thermal overload devices will not prevent MOVs from performing their safety related function. An acceptable method to ensure completion of a safety related function is to ensure that thermal overload protection devices that are normally in place during plant operation be bypassed under accident conditions and should be tested periodically. Section 8.1.6.1.19 of the UFSAR states that RG 1.106 is not applicable to Exelon per the implementation section, but concludes Exelon is in conformance with RG 1.106. In addition, Section 8.1.6.1.19a states that MOVs with spring-to-return control switches, during manual operation, the thermal overload is normally in the trip circuit; however, the thermal overload can be bypassed by holding the control switch in the appropriate open or close position. The team verified that operators were not expected to hold the switch in order to bypass the thermal overload during an accident condition. The team questioned if Exelon was meeting the intent of TS 3.8.4.2 because thermal overloads are not bypassed during an accident unless the overloads have been actuated and operators reposition the switch and hold it in the open or closed position. Exelon initiated issue report (IR) 985060 to review the issue and concluded in a position paper that they are in compliance with TS 3.8.4.2b. Additionally, the team questioned the adequacy of testing of the thermal overload bypasses for spring-to-return control switches for manually operated Class 1E MOVs in accordance with SR 4.8.4.2.2. The surveillance requires a Channel Functional Test to be performed to verify that the thermal overload protection will be bypassed under accident conditions. Exelon\'s TS, Section 1.6a, defines Channel Functional Test for analog channels as the injection of a simulated signal into the channel as close to the sensor as practicable to verify operability including alarm and/or trip functions. The test performed to satisfy the SR cycles the valve remotely with the control switch to check the continuity of the bypass circuitry but does not verify operation of the alarm associated with a thermal overload condition. The team questioned whether Exelon was required to verify the alarm function associated with the thermal overloads. In response to the team\'s questions, Exelon supported a position that standard operating practice includes verification of valve position by the operators using valve indication lights and that the alarm function does not need to be tested. This issue will be opened as a URI pending further NRC review in order to determine if LGS Units 1 & 2 are in compliance with their TS section 3.8.4.2 and SR 4.8.4.2.2 for thermal overload bypass operation in accident conditions and testing of the thermal overload alarm function. (URI 05000352,353/2009006-02, TS Requirements for MOV Thermal Overload Bypass Feature) |
| Site: | Limerick  |
|---|---|
| Report | IR 05000352/2009006 Section 1R21 |
| Date counted | Dec 31, 2009 (2009Q4) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.21 |
| Inspectors (proximate) | J Richmond K Mangan E Huang L Hajos S Spiegelman M Balazik L Doerflein J Hawkins J Rady M Orr |
| INPO aspect | |
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Finding - Limerick - IR 05000352/2009006 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Limerick) @ 2009Q4
Self-Identified List (Limerick)
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