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Pacific Gas and Electric (PG&E) is supPacific Gas and Electric (PG&E) is supplying this information as a voluntary report. On March 8, 2012, at 1850 PST, Diablo Canyon Power Plant (DCPP), Unit 1, declared the steam generator (SG) 1-1 narrow-range, low-low, water level channels for level transmitters LT-517 and LT-519 inoperable. This resulted from DCPP determining that the low-low setpoints were non-conservative as a result of its evaluation of the Rosemount Nuclear's 10 CFR Part 21 notification titled 'Notification Under 10 CFR Part 21 on Certain Rosemount Model 1154 Series H Pressure Transmitters,' dated March 2, 2012. </br>PG&E determined that the following SG narrow-range level transmitters having reactor protection and emergency safeguards actuation functions are affected:</br>Unit 1:</br>- two channels on SG 1-1 </br>- one channel each on SGs 1-2 and 1-4</br>Unit 2:</br>- one channel each on SGs 2-1, 2-2, 2-3 and 2-4</br>The Part 21 notification identified that the high temperature/pressure accuracy specification changed for certain transmitters which have higher impedance resistors installed in their temperature compensation circuitry. PG&E's evaluation concluded that narrow range SG low-low level setpoint uncertainty increased by as much as 2 percent of span due to the revised specification. Under the most limiting conditions, this deficiency could result in a short delay in relay actuation.</br>At 1953 PST, DCPP personnel declared the LT-517 and LT-519 water level low-low channels for SG 1-1 to be operable after adjusting the low-low setpoints from 15 percent to 17 percent on SG 1-1. DCPP also changed the low-low setpoints on SG 1-2 and SG 1-4 on March 8, 2012, and is changing this setpoint on all four of the Unit 2 SGs.</br>PG&E plans to submit a Licensee Event Report on this issue.</br>Plant personnel notified the NRC Resident Inspector.ssue. Plant personnel notified the NRC Resident Inspector.  +
02:50:00, 9 March 2012  +
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19:17:00, 9 March 2012  +
02:50:00, 9 March 2012  +
Pacific Gas and Electric (PG&E) is supPacific Gas and Electric (PG&E) is supplying this information as a voluntary report. On March 8, 2012, at 1850 PST, Diablo Canyon Power Plant (DCPP), Unit 1, declared the steam generator (SG) 1-1 narrow-range, low-low, water level channels for level transmitters LT-517 and LT-519 inoperable. This resulted from DCPP determining that the low-low setpoints were non-conservative as a result of its evaluation of the Rosemount Nuclear's 10 CFR Part 21 notification titled 'Notification Under 10 CFR Part 21 on Certain Rosemount Model 1154 Series H Pressure Transmitters,' dated March 2, 2012. </br>PG&E determined that the following SG narrow-range level transmitters having reactor protection and emergency safeguards actuation functions are affected:</br>Unit 1:</br>- two channels on SG 1-1 </br>- one channel each on SGs 1-2 and 1-4</br>Unit 2:</br>- one channel each on SGs 2-1, 2-2, 2-3 and 2-4</br>The Part 21 notification identified that the high temperature/pressure accuracy specification changed for certain transmitters which have higher impedance resistors installed in their temperature compensation circuitry. PG&E's evaluation concluded that narrow range SG low-low level setpoint uncertainty increased by as much as 2 percent of span due to the revised specification. Under the most limiting conditions, this deficiency could result in a short delay in relay actuation.</br>At 1953 PST, DCPP personnel declared the LT-517 and LT-519 water level low-low channels for SG 1-1 to be operable after adjusting the low-low setpoints from 15 percent to 17 percent on SG 1-1. DCPP also changed the low-low setpoints on SG 1-2 and SG 1-4 on March 8, 2012, and is changing this setpoint on all four of the Unit 2 SGs.</br>PG&E plans to submit a Licensee Event Report on this issue.</br>Plant personnel notified the NRC Resident Inspector.ssue. Plant personnel notified the NRC Resident Inspector.  +
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Modification date"Modification date" is a predefined property that corresponds to the date of the last modification of a subject and is provided by <a rel="nofollow" class="external text" href="https://www.semantic-mediawiki.org/wiki/Help:Special_properties">Semantic MediaWiki</a>.
02:04:40, 2 March 2018  +
19:17:00, 9 March 2012  +
false  +
0.685 d (16.45 hours, 0.0979 weeks, 0.0225 months)  +
02:50:00, 9 March 2012  +
Inoperable Steam Generator Narrow Range Level Transmitters Due to Part 21 Concern  +
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