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On December 21, 2011, at 1359 hours EST, i … On December 21, 2011, at 1359 hours EST, it was determined that the test instruction for the weekly groundwater level readings contained non-conservative acceptance criteria. The test instruction acceptance criteria for groundwater level exceeds the initial assumptions used in the Updated Safety Analysis Report (USAR) Chapter 15 accident analysis for 'Postulated Radioactive Releases due to Liquid Containing Tank Failures.' The issue was identified during the conduct of a prompt functionality assessment evaluating the plant underdrain system performance and to ensure all USAR described functions were being met.</br>The test instruction acceptance criteria is less than 575 feet. The calculation supporting the Chapter 15 accident analysis assumes an initial groundwater elevation of 568 feet in order to accumulate a sufficient volume of groundwater to dilute the tank inventory prior to exiting the underdrain system. The accumulation volume results in hold up time allowing for mixing and radioactive decay. With the degraded performance of the underdrain system pumps and high precipitation, the groundwater level had risen above 568 feet but was still less than 575 feet. A preliminary engineering evaluation has determined that significant margin exists in the calculation. A calculation revision is being pursued in parallel with this notification.</br>Compensatory actions involving the repair of 1 permanent non-safety pump and installation of temporary pumps were previously initiated and the groundwater levels are decreasing. Restoration of the remaining permanent plant pumps continues.</br>The NRC Resident Inspector has been notified.</br>* * * RETRACTION ON 2/15/12 AT 1315 EST FROM LLOYD ZERR TO ERIC SIMPSON * * *</br>The calculation supporting the USAR Chapter 15 accident analysis was reviewed and subsequently revised. The revised calculation verifies and initial groundwater elevation of 575 feet is consistent with the preliminary assessment that substantial margin existed in the calculation for the underdrain system. Because the condition reported in Event Number 47545 was not an event or condition that results in the nuclear power plant being in an unanalyzed condition that degrades safety, the condition is not reportable, and this notification is retracted. The evaluation for this condition is documented in condition report 2011-07169.</br>The NRC Resident Inspector and R3DO (Passehl) were notified.nspector and R3DO (Passehl) were notified.
18:59:00, 21 December 2011 +
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21:37:00, 21 December 2011 +
18:59:00, 21 December 2011 +
On December 21, 2011, at 1359 hours EST, i … On December 21, 2011, at 1359 hours EST, it was determined that the test instruction for the weekly groundwater level readings contained non-conservative acceptance criteria. The test instruction acceptance criteria for groundwater level exceeds the initial assumptions used in the Updated Safety Analysis Report (USAR) Chapter 15 accident analysis for 'Postulated Radioactive Releases due to Liquid Containing Tank Failures.' The issue was identified during the conduct of a prompt functionality assessment evaluating the plant underdrain system performance and to ensure all USAR described functions were being met.</br>The test instruction acceptance criteria is less than 575 feet. The calculation supporting the Chapter 15 accident analysis assumes an initial groundwater elevation of 568 feet in order to accumulate a sufficient volume of groundwater to dilute the tank inventory prior to exiting the underdrain system. The accumulation volume results in hold up time allowing for mixing and radioactive decay. With the degraded performance of the underdrain system pumps and high precipitation, the groundwater level had risen above 568 feet but was still less than 575 feet. A preliminary engineering evaluation has determined that significant margin exists in the calculation. A calculation revision is being pursued in parallel with this notification.</br>Compensatory actions involving the repair of 1 permanent non-safety pump and installation of temporary pumps were previously initiated and the groundwater levels are decreasing. Restoration of the remaining permanent plant pumps continues.</br>The NRC Resident Inspector has been notified.</br>* * * RETRACTION ON 2/15/12 AT 1315 EST FROM LLOYD ZERR TO ERIC SIMPSON * * *</br>The calculation supporting the USAR Chapter 15 accident analysis was reviewed and subsequently revised. The revised calculation verifies and initial groundwater elevation of 575 feet is consistent with the preliminary assessment that substantial margin existed in the calculation for the underdrain system. Because the condition reported in Event Number 47545 was not an event or condition that results in the nuclear power plant being in an unanalyzed condition that degrades safety, the condition is not reportable, and this notification is retracted. The evaluation for this condition is documented in condition report 2011-07169.</br>The NRC Resident Inspector and R3DO (Passehl) were notified.nspector and R3DO (Passehl) were notified.
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21:37:00, 21 December 2011 +
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18:59:00, 21 December 2011 +
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