05000424/FIN-2007006-03
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Finding | |
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Title | Ability to Satisfy TS SR 3.7.5.2. |
Description | The inspectors review of design calculation X4C1302S12, Auxiliary Feedwater Pump Discharge Line Orifice Sizing, Rev. 1 and calculation X4C1302V04, Auxiliary Feedwater Pumps Technical Specifications Verification, Rev. 5 identified the following concerns: The results of calculation X4C1302S12 were not incorporated into calculation X4C1302V04. Specifically, the resistance values for orifices currently installed in the system were not used in the calculation to determine if the system could satisfy the intended safety function by providing above the total minimum flow of 510 gpm. The inspectors determined that the failure to incorporate the results of calculation X4C1302S12 into calculation X4C1302V04 resulted in non-conservative acceptance criteria for the MDAFW pumps. The acceptance criterion for the TDAFW pumps was not based on a fluid specific gravity of 1.0. A lower value was used based on an assumed condensate storage tank (CST) temperature of 100 degrees F. This is a non-conservative assumption since the actual CST temperature was lower than this value on every test conducted over the last two years. The acceptance criteria for both TDAFW and MDAFW pumps did not include any allowances for instrument uncertainties. The inspectorss review of 20 completed pump surveillances 14810-1, TDAFW Pump Operability, Response Time and Check Valve IST, Rev. 36.2 and 14810-2, TDAFW Pump Operability, Response Time and Check Valve IST, Rev. 30.2 from March 2005 through April 2007 identified the following concerns: The results of the TDAFW surveillances were not corrected for an assumed CST temperature of 100 degrees F. The test results were not normalized to a required speed of 4230 rpm. The Terry turbine speed was changed from 4200 to 4230 rpm by a plant change MDD-91-V1M016, Auxiliary Feedwater Rated Speed Change, April 4, 1991 to increase the TS margin. The inspectors review identified that five surveillance tests had recorded the as-found turbine speed to be 4200 rpm. The licensee generated CR 2007105895 on May 23, 2007 to address this issue. The test results were not corrected for the applicable instrument error. The licensee generated a documentation of engineering judgment (DOEJ) DOEJSJ- C070401401-001, Channel Uncertainty AFW Pump Suction and Discharge Pressures P-5110, P-5107, dated May 7, 2007, which demonstrated that the combined instrument uncertainty for both suction and discharge gauges is 28.6 psig, when using information from the plant computer. The licensee also evaluated the effects of the temperature correction and concluded that the recent TDAFWP test results when corrected for both instrument uncertainty and temperature met the acceptance criterion. The licensee generated CR 2007105436 and CR 2007105713 to address the inspectors concerns. The inspectors review of completed pump surveillances 14807-1, Motor Driven Auxiliary Feedwater Pump and Check Valve In-Service and Response Time Test, Rev. 29.2 and 14807-2, Motor Driven Auxiliary Feedwater Pump and Check Valve In-Service and Response Time Test, Rev. 24.1 from March 2005 through April 2007 identified that similar to the TDAFW pumps, the test results for the MDAFW pumps were not corrected for the instrument error. |
Site: | Vogtle |
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Report | IR 05000424/2007006 Section 1R21 |
Date counted | Jun 30, 2007 (2007Q2) |
Type: | URI: |
cornerstone | Mitigating Systems |
Identified by: | NRC identified |
Inspection Procedure: | IP 71111.21 |
Inspectors (proximate) | R Berryman B Collins T Chandler S Shaeffer L Lake G Mccoy C Peabodym Shlyambergs Rose D Mas-Penaranda J Chiloyan R Berryman |
INPO aspect | |
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Finding - Vogtle - IR 05000424/2007006 | |||||||||||||||||
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Finding List (Vogtle) @ 2007Q2
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