ENS 52253
ENS Event | |
|---|---|
20:50 Sep 19, 2016 | |
| Title | Control Room Emergency Ventilation Charcoal Not Meeting Acceptance Criteria |
| Event Description | At 1550 [CDT] on September 19, 2016, Dresden received the Methyl Iodide Penetration test results for the Control Room Emergency Ventilation (CREVS) charcoal. The test results did not meet technical specification acceptance criteria. This results in the inoperability of CREVS. CREVS is a single train system and therefore is reportable per 10CFR50.72(b)(3)(v)(D). The Air Filtration Unit (AFU) is required to operate during a design basis accident to maintain Main Control Room habitability. This places unit 2 and unit 3 in a 7 day LCORA [Limiting Condition of Operation Required Action] per Tech Spec 3.7.4 Required Action A.1.
The licensee notified the NRC Resident Inspector.
The licensee is retracting this report based on the following: The purpose of this notification is to retract ENS notification 52253 made on September 19th, 2016, for Dresden Nuclear Power Station. After further evaluation and testing, it has been determined that the Control Room Emergency Ventilation System (CREVS) charcoal would have fulfilled its safety function given the Methyl Iodide Penetration test results. The initial tests were performed with a 2 inch bed depth due to a difference in batches used in each charcoal filter, but testing at a 4 inch bed depth is the correct testing methodology for Dresden's configuration. At a 4 inch bed depth, the test results met the Technical Specification acceptance criteria with significant margin. Therefore, this event does not meet the criteria of 10 CFR 50.72(b)(3)(v)(D) and the ENS report is being retracted. The NRC Resident Inspector has been notified. Notified R3DO (Orlikowski). |
| Where | |
|---|---|
Dresden  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:+0.83 h0.0346 days <br />0.00494 weeks <br />0.00114 months <br />) | |
| Opened: | Henry Waters 21:40 Sep 19, 2016 |
| NRC Officer: | Vince Klco |
| Last Updated: | Mar 23, 2017 |
| 52253 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Unit 3 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (87 %) |
| After | Power Operation (87 %) |