ML12249A367: Difference between revisions
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{{#Wiki_filter:Date: September 5, 2012 | |||
PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE -- PNO-I-12-006A This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by the Region I staff on this date. | |||
Facility Licensee Emergency Classification Exelon Generation Company, LLC Three Mile Island Unit 1 Middletown, PA Docket: 50-289 License: DPR-50 | |||
_ Notification of Unusual Event | |||
_ Alert _ Site Area Emergency | |||
_ General Emergency X Not Applicable | |||
==SUBJECT:== | |||
UPDATE - THREE MILE ISLAND (TMI) SHUTDOWN DUE TO REACTOR COOLANT SYSTEM LEAK | |||
This Preliminary Notification updates information discussed in PNO-I-12-006, which described a plant shutdown on August 22, 2012 due to reactor coolant system (RCS) leakage. | |||
The plant reached cold shutdown on August 23, 2012, and the source of RCS leakage was confirmed to be from micro-cracks in the alloy 600 diaphragm for the upper pressurizer heater bundle. This heater bundle was subsequently replaced with a bundle that contained a stainless steel, non-alloy 600 heater diaphragm. An NRC specialist inspector, who was deployed to the site, confirmed the source of the RCS leakage and monitored pressurizer heater replacement activities. The licensee subsequently conducted extent-of-condition inspections on the other two pressurizer heater bundles and no indications of leakage were identified. The inspectors determined that the licensee's post-installation and extent-of-condition inspections were acceptable. | |||
Once all repair activities were completed, operators proceeded with reactor heatup and plant startup. No additional RCS leakage was observed. Reactor startup was commenced on September 3, 2012, and full power was achieved on September 5. The resident inspectors monitored licensee activities throughout the initial shutdown and subsequent startup. | |||
This information has been reviewed with TMI plant management. This preliminary notification is issued for information only and no further update by the staff is planned. | |||
ADAMS Accession Number: | |||
ML12249A367 CONTACT: Gordon Hunegs (610) 337-5046 | |||
: ML12249A367 SUNSI Review Non-Sensitive Sensitive Publicly Available Non-Publicly Available OFFICE RI/DRP RI/SLO RI/PAO RI/DRP RI/DRP RI/ORA NAME SBarber/ SB NMcNamara/ NM DScrenci/DS via email GHunegs/GKH DRoberts/ DJR WDean/DCL for DATE 09/ 05/12 09/05 /12 09/05/12 09/05 /12 09/05/12 09/05/12}} | |||
Revision as of 22:33, 1 August 2018
| ML12249A367 | |
| Person / Time | |
|---|---|
| Site: | Three Mile Island  |
| Issue date: | 09/05/2012 |
| From: | Hunegs G K NRC/RGN-I/DRP/PB6 |
| To: | |
| Hunegs G K | |
| References | |
| PNO-I-12-006A | |
| Download: ML12249A367 (2) | |
Text
Date: September 5, 2012
PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE -- PNO-I-12-006A This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by the Region I staff on this date.
Facility Licensee Emergency Classification Exelon Generation Company, LLC Three Mile Island Unit 1 Middletown, PA Docket: 50-289 License: DPR-50
_ Notification of Unusual Event
_ Alert _ Site Area Emergency
_ General Emergency X Not Applicable
SUBJECT:
UPDATE - THREE MILE ISLAND (TMI) SHUTDOWN DUE TO REACTOR COOLANT SYSTEM LEAK
This Preliminary Notification updates information discussed in PNO-I-12-006, which described a plant shutdown on August 22, 2012 due to reactor coolant system (RCS) leakage.
The plant reached cold shutdown on August 23, 2012, and the source of RCS leakage was confirmed to be from micro-cracks in the alloy 600 diaphragm for the upper pressurizer heater bundle. This heater bundle was subsequently replaced with a bundle that contained a stainless steel, non-alloy 600 heater diaphragm. An NRC specialist inspector, who was deployed to the site, confirmed the source of the RCS leakage and monitored pressurizer heater replacement activities. The licensee subsequently conducted extent-of-condition inspections on the other two pressurizer heater bundles and no indications of leakage were identified. The inspectors determined that the licensee's post-installation and extent-of-condition inspections were acceptable.
Once all repair activities were completed, operators proceeded with reactor heatup and plant startup. No additional RCS leakage was observed. Reactor startup was commenced on September 3, 2012, and full power was achieved on September 5. The resident inspectors monitored licensee activities throughout the initial shutdown and subsequent startup.
This information has been reviewed with TMI plant management. This preliminary notification is issued for information only and no further update by the staff is planned.
ADAMS Accession Number:
ML12249A367 CONTACT: Gordon Hunegs (610) 337-5046
- ML12249A367 SUNSI Review Non-Sensitive Sensitive Publicly Available Non-Publicly Available OFFICE RI/DRP RI/SLO RI/PAO RI/DRP RI/DRP RI/ORA NAME SBarber/ SB NMcNamara/ NM DScrenci/DS via email GHunegs/GKH DRoberts/ DJR WDean/DCL for DATE 09/ 05/12 09/05 /12 09/05/12 09/05 /12 09/05/12 09/05/12