05000456/FIN-2012003-07
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Finding | |
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| Title | Removal of TRM 3.3.y Requirement Via 10 CFR 50.59 Evaluation |
| Description | On May 28, 2012, the 1A MSIV active-side hydraulic accumulator pressure was found at 3450 psig, which was below the operability limit of 4800 psig. This prevented manual isolation of the 1A steam line via the main control room switch, which required the active-side accumulator and was required by TRM 3.3.y Condition D. Each MSIV also had a standby-side accumulator that could redundantly close the valve if an ESFAS signal was received, but not from the individual isolation control switch. The 1A MSIV standby accumulator pressure was 5400 psig, thus the 1A MSIV could have been closed by an ESFAS signal and therefore remained operable. The action statement for TRM 3.3.y Condition D required restoration of the individual steam line isolation capability within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />. If that was not done, Condition D required the MSIV to be declared inoperable and TS 3.7.2 Condition A.1 to be entered, which required the MSIV to be operable within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> or enter Condition B.1, which required the Unit to be in Mode 2 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. During troubleshooting of the 1A MSIV active-side accumulator pressure issue, the licensee became concerned that they would not find and repair the active-side hydraulic problem prior to the requirement to enter Mode 2. As a result, the licensee elected to remove TRM 3.3.y Condition D from the TRM through the 10 CFR 50.59 evaluation process. As a result, the licensee would not be required to declare the 1A MSIV inoperable provided the standby-side accumulator pressure was within operability limits. The inspectors reviewed the 10 CFR 50.59 evaluation of this change and questioned the licensees response to Question 2, which asked, Does the proposed activity result in a more than minimal increase in the likelihood of occurrence of a malfunction of an SSC important to safety previously evaluated in the UFSAR? The licensee concluded that it did not. However, the inspectors noted that TRM 3.3.y Condition D was the only requirement for any particular MSIV accumulator, standby or active, to be operable. The inspectors were concerned that removing the requirement increased the likelihood that an active-side hydraulic accumulator would be inoperable, which increased the likelihood that the hydraulic system would fail to operate the 1A MSIV, which would constitute an increase in the likelihood of a malfunction of the 1A MSIV. Furthermore, the inspectors noted that the licensees response to Question 2 credited the redundancy of the hydraulic system (active and standby accumulators) in coming to the conclusion that the change does not increase the likelihood of a malfunction of an SSC, despite removing the only requirement which helped ensure that redundancy. At the end of the inspection period, the inspectors had not completed their review of the 10 CFR 50.59 evaluation. As a result, this URI will remain open pending a full review of the applicable documentation. |
| Site: | Braidwood  |
|---|---|
| Report | IR 05000456/2012003 Section 1R15 |
| Date counted | Jun 30, 2012 (2012Q2) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.15 |
| Inspectors (proximate) | M Perry R Ng R Walton T Go A Garmoe A Shaikh B Metrow E Duncan J Benjamin M Holmbergm Learnm Perry N Feliz Adorno R Edwards R Ng T Daun T Go V Meghani A Dahbur A Dunlop A Garmoe A Sallman E Duncan J Benjamin J Neurauter J Robbins |
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Finding List (Braidwood) @ 2012Q2
Self-Identified List (Braidwood)
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