ML21078A095: Difference between revisions
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{{#Wiki_filter:}} | {{#Wiki_filter:Risk Informed Completion Times Licensee Experience James T. Petty Director of Site Operations Braidwood Generating Station - Exelon Nuclear | ||
TSTF-505 Overview | |||
* TSTF-505 license amendment requests (LAR) approval for Braidwood in March 2020. | |||
* A new Risk-Informed Completion Time (RICT) program was added to the Administrative Controls section of TS | |||
* RICT is only applied in Modes 1 and 2 (Exelon does not have a Shutdown PRA so Modes 3 and 4 were not included) | |||
* RICT may not exceed 30 days | |||
* If TS LCO is not restored prior to reaching RICT, then TS requirements for plant shutdown or other remedial action become applicable | |||
* RICT is not permitted for a loss of TS safety function configuration or inoperability of all required safety trains | |||
* Impacts on baseline CDF and LERF are periodically monitored | |||
TSTF-505 Benefits | |||
* Emphasis on risk-significant configurations | |||
* Increased control of plant configuration during SSC unavailability | |||
* Avoided shutdowns = Avoided safety challenges | |||
* Reduced use of NOEDs | |||
* Increased flexibility in scheduling maintenance | |||
* Shorter, less-complex refueling outages - Outage work moved online | |||
* Reduced organizational stress with short work windows | |||
* Increased plant availability and capacity factors | |||
RICT Examples at Braidwood | |||
* Station Auxiliary Transformer (SAT) work window - Fall 2020 | |||
* Normally requires 3 separate 72-hour LCO windows to complete all PMs on both transformers. | |||
* Work window scope revision with RICT requires a single LCO window. | |||
* Results in less EDG and equipment manipulations. | |||
* Component Cooling Water (CC) system Heat Exchanger (HX) work - Winter 2021 | |||
* CC HX flange degradation identified in 2011 required repairs to ensure minimum wall criteria/maximum allowable wall stresses are maintained. | |||
* Outage work scope would have required an ~12-day work window that would be scheduled only 12 hours off outage critical path. | |||
* 51 hours of scope expansion contingency work would potentially challenge overall outage duration and goals. | |||
* Significant challenge to Shutdown Safety profile and Shutdown Cooling availability.}} |
Revision as of 19:16, 19 January 2022
ML21078A095 | |
Person / Time | |
---|---|
Site: | Braidwood ![]() |
Issue date: | 03/08/2021 |
From: | Petty J Exelon Nuclear |
To: | NRC/RGN-III |
References | |
Download: ML21078A095 (4) | |
Text
Risk Informed Completion Times Licensee Experience James T. Petty Director of Site Operations Braidwood Generating Station - Exelon Nuclear
TSTF-505 Overview
- A new Risk-Informed Completion Time (RICT) program was added to the Administrative Controls section of TS
- RICT is only applied in Modes 1 and 2 (Exelon does not have a Shutdown PRA so Modes 3 and 4 were not included)
- RICT may not exceed 30 days
- If TS LCO is not restored prior to reaching RICT, then TS requirements for plant shutdown or other remedial action become applicable
- RICT is not permitted for a loss of TS safety function configuration or inoperability of all required safety trains
TSTF-505 Benefits
- Emphasis on risk-significant configurations
- Increased control of plant configuration during SSC unavailability
- Avoided shutdowns = Avoided safety challenges
- Reduced use of NOEDs
- Increased flexibility in scheduling maintenance
- Shorter, less-complex refueling outages - Outage work moved online
- Reduced organizational stress with short work windows
- Increased plant availability and capacity factors
RICT Examples at Braidwood
- Station Auxiliary Transformer (SAT) work window - Fall 2020
- Normally requires 3 separate 72-hour LCO windows to complete all PMs on both transformers.
- Work window scope revision with RICT requires a single LCO window.
- Results in less EDG and equipment manipulations.
- CC HX flange degradation identified in 2011 required repairs to ensure minimum wall criteria/maximum allowable wall stresses are maintained.
- Outage work scope would have required an ~12-day work window that would be scheduled only 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> off outage critical path.
- 51 hours5.902778e-4 days <br />0.0142 hours <br />8.43254e-5 weeks <br />1.94055e-5 months <br /> of scope expansion contingency work would potentially challenge overall outage duration and goals.
- Significant challenge to Shutdown Safety profile and Shutdown Cooling availability.