ENS Event | |
|---|---|
14:18 Nov 12, 2010 | |
| Title | Control Room Outside Air Intake Noble Gas Channel Setpoints Non-Conservative |
| Event Description | At 0818 CST, 11/12/10, Radiation Protection determined that the setpoints for the Control Room Outside Air Intake Noble Gas channels are non-conservative. This affects Tech Spec 3.3.7 required monitors 0PR31B, 0PR32B, 0PR33B and 0PR34B (Noble gas channels). The current setpoints for 0PR31B, 0PR32B, 0PR33B and 0PR34B are High Alarm 9.55E-05 microCi/cc and Alert Alarm 9.55E-06 microCi/ml. The calculated required setpoints are High Alarm 6.61E-05 microCi/cc and Alert Alarm 6.61E-06 microCi/cc. This is approximately a 30% decrease in setpoints from the current setpoints. LCO 3.3.7 conditions A and B were entered at 0818, 11/12/10. LCO 3.3.7 conditions A and B required actions completion time is 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. All required actions were complete at 0900 11/12/10, less than 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />.
This report is being made per 10 CFR 50.72(b)(3)(v), Event or condition that could have prevented fulfillment of a safety function, 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> non-emergency notification. Both trains of radiation monitor setpoints were non-conservative and actuate control room ventilation in emergency mode. The margin available in the control room dose analysis will be reviewed to confirm impact on safety function. The setpoints have been non-conservative since 1999. The licensee notified the NRC Resident Inspector.
At 0818 CST, 11/12/2010, Radiation Protection determined that the setpoints for the Control Room Outside Air Intake Noble Gas channels are non-conservative. This affects Tech Spec 3.3.7 required monitors 0PR31B, 0PR32B, 0PR33B, 0PR34B (Noble Gas channels). ENS notification was made under ENS 46414 under 10 CFR 50.72(b)(3)(v)(D). The design basis accidents do not credit automatic actuation of the Control Room Outside Air Intake system to the Emergency mode from a high radiation signal. Therefore, the high radiation signal is not needed to mitigate the consequences of an accident and this event did not result in a safety system functional failure. Therefore, ENS notification 46414 is being retracted. The licensee notified the NRC resident inspector. Notified R3DO (Bloomer) |
| Where | |
|---|---|
Braidwood  Illinois (NRC Region 3) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
| Time - Person (Reporting Time:+1.43 h0.0596 days <br />0.00851 weeks <br />0.00196 months <br />) | |
| Opened: | Mike Deboard 15:44 Nov 12, 2010 |
| NRC Officer: | Donald Norwood |
| Last Updated: | Jan 20, 2011 |
| 46414 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Braidwood with 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | |
WEEKMONTHYEARENS 519592016-05-25T19:15:00025 May 2016 19:15:00
[Table view]10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Discovery of Non-Conforming Conditions During Tornado Hazards Analysis ENS 464142010-11-12T14:18:00012 November 2010 14:18:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Control Room Outside Air Intake Noble Gas Channel Setpoints Non-Conservative ENS 462032010-08-24T16:40:00024 August 2010 16:40:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident, 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition Essential Service Water Placed in a Line-Up That May Have Prevented Its Safety Function ENS 443542008-07-17T16:41:00017 July 2008 16:41:00 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident Degraded Control Room Ventilation Envelope 2016-05-25T19:15:00 | |