ENS 50207
ENS Event | |
---|---|
22:29 Jun 17, 2014 | |
Title | Technical Specification Shutdown Due to Loss of a and B Control Bay Chiller Trains |
Event Description | At 1729 [CDT] on June 17, 2014 Browns Ferry Units 1, 2, and 3 initiated actions to commence a reactor shutdown to comply with TS LCO [Technical Specifications Limiting Condition of Operation] 3.0.3. TS LCO 3.0.3 was entered at 1632 and was required due to the concurrent loss of 'A' and 'B' Control Bay Chiller units which resulted in loss of cooling to the U1 and U2 4kV Shutdown Board Rooms. Required actions for the loss of cooling to the U1 and U2 4kV Shutdown Board Rooms is to declare the electrical equipment in the 4kV Shutdown Board Rooms inoperable. The declaration of inoperability of the equipment supported by the U1 and U2 4kV Shutdown Boards resulted in TS LCO 3.0.3 for Units 1, 2 and 3. TS LCO 3.0.3 requires actions to be initiated within one hour to place the units in MODE 2 within 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br />; MODE 3 within 13 hours1.50463e-4 days <br />0.00361 hours <br />2.149471e-5 weeks <br />4.9465e-6 months <br />; and MODE 4 within 37 hours4.282407e-4 days <br />0.0103 hours <br />6.117725e-5 weeks <br />1.40785e-5 months <br />.
This event requires a 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> report IAW 50.72(b)(2)(i), 'The initiation of any nuclear plant shutdown required by the plant's Technical Specifications.' The NRC Resident Inspector has been notified. Service Request 899734 was initiated in the Corrective Action Program. The 'B' Control Bay Chiller train was operating when the control room entered the Loss of Chilling procedure. The 'A' Control Bay Chiller train was started to supply Control Bay cooling, and the 'A' train unit tripped during start. The failure affected unit-3 because each unit has a 50% capacity common standby gas treatment system. The loss of the the U1 and U2 4kV shutdown boards failed two of the three systems.
"'A' Control Bay Chiller declared operable at 2035 CDT. TS LCO 3.0.3 exited and plant shutdowns have been secured." The licensee will be notifying the NRC Resident Inspector. Notified R2DO (Haag) |
Where | |
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Browns Ferry Alabama (NRC Region 2) | |
Reporting | |
10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown | |
Time - Person (Reporting Time:+-0.73 h-0.0304 days <br />-0.00435 weeks <br />-9.99954e-4 months <br />) | |
Opened: | Todd Bohanan 21:45 Jun 17, 2014 |
NRC Officer: | Jeff Rotton |
Last Updated: | Jun 17, 2014 |
50207 - NRC Website
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Unit 1 | |
---|---|
Reactor critical | Critical |
Scram | No |
Before | Power Operation (100 %) |
After | Power Operation (98 %) |
Unit 2 | |
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Reactor critical | Critical |
Scram | No |
Before | Power Operation (96 %) |
After | Power Operation (94 %) |
Unit 3 | |
---|---|
Reactor critical | Critical |
Scram | No |
Before | Power Operation (100 %) |
After | Power Operation (98 %) |
WEEKMONTHYEARENS 536782018-10-21T05:00:00021 October 2018 05:00:00
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