ML15069A185: Difference between revisions
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{{#Wiki_filter:PRELIMINARY NOTIFICATION | {{#Wiki_filter:PRELIMINARY NOTIFICATION March 10, 2015 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE-PNO-III-15-003 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. Some of the information may not yet be fully verified or evaluated by the Region III staff. | ||
Facility Prairie Island Nuclear Plant Northern States Power Co. Welch, MN Docket: 50-306 License: DPR-60 Licensee Emergency Classification X Notification of Unusual Event Alert Site Area Emergency General Emergency Not Applicable | |||
==SUBJECT:== | ==SUBJECT:== | ||
SHUTDOWN OF PRAIRIE ISLAND UNIT 2 DUE TO LOSS OF INSTRUMENT AIR TO CONTAINMENT BUILDING AND NOTIFICATION OF UNUSUAL EVENT | SHUTDOWN OF PRAIRIE ISLAND UNIT 2 DUE TO LOSS OF INSTRUMENT AIR TO CONTAINMENT BUILDING AND NOTIFICATION OF UNUSUAL EVENT Prairie Island Unit 2 was shut down on March 5, 2015, after a valve s upplying instrument air to the containment building failed. During the shutdown, a vent cap known as a "rupture disk" passed steam and water from a pressure tank inside the Unit 2 containment building, triggering a nearby fire alarm. The fire alarm resulted in the licensee declaring a Notification of Unusual Event. After the shutdown was completed, the licensee verified that no fire had actually occurred and subsequently exited the Notification of Unusual Event. | ||
Instrument air is used to operate many of the valves and components in the plant. Without instrument air, the plant was required to be shutdown by procedure. The licensee did so using the pressure tank inside containment. The rupture disk relieving water and steam was expected due to the length of time needed to complete the shutdown. Several thousand gallons of water drained into the Unit 2 containment building. This water was collected in the containment sump and was not released to the environment. After the shutdown, licensee staff and the NRC resident inspectors observed that the water had caused no significant damage to plant equipment. There was no risk to the public health and safety from this event. The NRC Resident Inspectors were promptly notified and were on site to monitor the shutdown of Unit 2. The Resident Inspectors and Region III staff will continue to monitor licensee's investigation of the event, the repair of affected equipment, and subsequent restart of the plant. This preliminary notification is issued for information only. State officials have been informed. | Instrument air is used to operate many of the valves and components in the plant. Without instrument air, the plant was required to be shutdown by procedure. The licensee did so using the pressure tank inside containment. The rupture disk relieving water and steam was expected due to the length of time needed to complete the shutdown. Several thousand gallons of water drained into the Unit 2 containment building. This water was collected in the containment sump and was not released to the environment. After the shutdown, licensee staff and the NRC resident inspectors observed that the water had caused no significant damage to plant equipment. There was no risk to the public health and safety from this event. | ||
The NRC Resident Inspectors were promptly notified and were on site to monitor the shutdown of Unit 2. The Resident Inspectors and Region III staff will continue to monitor licensee's investigation of the event, the repair of affected equipment, and subsequent restart of the plant. | |||
This preliminary notification is issued for information only. State officials have been informed. | |||
Region III received initial notification of this occurrence by the NRC Resident inspectors on site. The information presented herein has been discussed with the licensee, and is current as of 9:50 am CDT, on March 10, 2015. ADAMS Accession Number: ML15069A185 | Region III received initial notification of this occurrence by the NRC Resident inspectors on site. The information presented herein has been discussed with the licensee, and is current as of 9:50 am CDT, on March 10, 2015. | ||
ADAMS Accession Number: ML15069A185 CONTACT: Nirodh Shah 630-829-9821 | |||
Nirodh.Shah@nrc.gov}} | |||
Latest revision as of 04:17, 1 July 2018
| ML15069A185 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 03/10/2015 |
| From: | Nirodh Shah Division Reactor Projects III |
| To: | |
| References | |
| PNO-III-15-003 | |
| Download: ML15069A185 (1) | |
Text
PRELIMINARY NOTIFICATION March 10, 2015 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE-PNO-III-15-003 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. Some of the information may not yet be fully verified or evaluated by the Region III staff.
Facility Prairie Island Nuclear Plant Northern States Power Co. Welch, MN Docket: 50-306 License: DPR-60 Licensee Emergency Classification X Notification of Unusual Event Alert Site Area Emergency General Emergency Not Applicable
SUBJECT:
SHUTDOWN OF PRAIRIE ISLAND UNIT 2 DUE TO LOSS OF INSTRUMENT AIR TO CONTAINMENT BUILDING AND NOTIFICATION OF UNUSUAL EVENT Prairie Island Unit 2 was shut down on March 5, 2015, after a valve s upplying instrument air to the containment building failed. During the shutdown, a vent cap known as a "rupture disk" passed steam and water from a pressure tank inside the Unit 2 containment building, triggering a nearby fire alarm. The fire alarm resulted in the licensee declaring a Notification of Unusual Event. After the shutdown was completed, the licensee verified that no fire had actually occurred and subsequently exited the Notification of Unusual Event.
Instrument air is used to operate many of the valves and components in the plant. Without instrument air, the plant was required to be shutdown by procedure. The licensee did so using the pressure tank inside containment. The rupture disk relieving water and steam was expected due to the length of time needed to complete the shutdown. Several thousand gallons of water drained into the Unit 2 containment building. This water was collected in the containment sump and was not released to the environment. After the shutdown, licensee staff and the NRC resident inspectors observed that the water had caused no significant damage to plant equipment. There was no risk to the public health and safety from this event.
The NRC Resident Inspectors were promptly notified and were on site to monitor the shutdown of Unit 2. The Resident Inspectors and Region III staff will continue to monitor licensee's investigation of the event, the repair of affected equipment, and subsequent restart of the plant.
This preliminary notification is issued for information only. State officials have been informed.
Region III received initial notification of this occurrence by the NRC Resident inspectors on site. The information presented herein has been discussed with the licensee, and is current as of 9:50 am CDT, on March 10, 2015.
ADAMS Accession Number: ML15069A185 CONTACT: Nirodh Shah 630-829-9821
Nirodh.Shah@nrc.gov