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Nuclear Events: Automatic Reactor Scram – Susquehanna Nuclear Power Plant, Pennsylvania

2015/11/13

Technological Hazard – Nuclear Event: Reactor Shutdown

Susquehanna Nuclear Power Plant

Susquehanna Nuclear Power Plantt operated by PPL Susquehanna LLC., Luzerne County, Pennsylvania. Photo: Nuclear Power International

North America – USA | State of Pennsylvania, Berwick – Susquehanna Nuclear Power Plant
Location: 41°05’20.0″N 76°08’56.0″W
Present Operational Age: ~33 years
Emergency Level: RPS ACTUATION – CRITICAL – POT UNCNTRL RAD REL

Nuclear Event in USA on Thursday, 12 November, 2015 at 11:32 [EST].

Current Event Notification Reports

AUTOMATIC REACTOR SCRAM

“At 1132 hours [EST] on November 12, 2015, Susquehanna Steam Electric Station Unit 1 reactor automatically scrammed due to one Main Steam Isolation Valve (MSIV) unanticipated closure causing a High Pressure RPS [Reactor Protection System] trip.

“All control rods inserted and both reactor recirculation pumps tripped due to reactor water level 2. Reactor water level lowered to -37 inches causing Level 3 (+13 inches) and level 2 (-38 inches) (Division 2 only) isolations. RCIC [Reactor Core Isolation Cooling] automatically initiated and was overridden by control room operators after RPV [Reactor Pressure Vessel] water level was restored to the normal band with feedwater. All isolations and initiations occurred as expected. No main steam relief valves opened. Pressure was controlled via main turbine bypass valve operation. All safety systems operated as expected.

“The Unit 1 reactor is currently stable in Mode 3. Investigation into the cause of the MSIV closure is underway.

“Unit 2 was unaffected and continues power operation.

“The NRC Resident Inspector has been notified. A voluntary notification to PEMA [Pennsylvania Emergency Management Agency] and press release will occur.”

The plant is in its normal shutdown electrical lineup.

Source: NRC  Event Number:  51532


SECONDARY CONTAINMENT INOPERABLE

“On November 12, 2015 at 1132 hrs. [EST], Secondary Containment became inoperable due to failure to meet SR 3.6.4.1.1 requirements on Unit 2.

“The inoperability was caused when RB [Reactor Building] Zone II differential pressure [D/P] oscillated between 0.23 and 0.43 inches WG [water gauge] (less than SR 3.6.4.1.1 requirement of greater than or equal to 0.25 inches WG). The oscillations subsided at 1501 [EST] and RB Zone II D/P continues to be maintained at approximately 0.35 inches WG.

“This event is being reported under 10 CFR 50.72(b)(3)(v)(c) and per the guidance of NUREG 1022 Rev 3 section 3.2.7 as a loss of a Safety Function. There is no redundant Susquehanna Secondary Containment system.”

The licensee notified the NRC Resident Inspector.

Source: NRC  Event Number:  51533


Nuclear Event in USA on Friday, 13 November, 2015 at 03:36 (03:36 AM) UTC.

Officials are investigating the cause of the automatic shutdown Thursday of Unit 1 at Talen Energy Corp.’s Susquehanna nuclear power plant. Talen spokesman Todd Martin said a cause of the shutdown had not been determined. He also said it was premature to speculate when the unit would return to service. No one was injured inside the plant, and the public is not in any danger, he said. “Susquehanna’s nuclear professionals are investigating the exact cause of the shutdown and have confirmed that all systems are responding as expected,” Jon Franke, Susquehanna site vice president, said in a news release. “Our operators followed established procedures and kept the unit in a safe and stable condition. We will ensure the cause of the shutdown is corrected prior to restarting Unit 1.” Martin added that all appropriate federal and state agencies have been notified, including the U.S. Nuclear Regulatory Commission. NRC Spokesman Neil Sheehan said a preliminary review indicated that the reactor tripped due to high pressure levels. During testing on a main steam line, it apparently resulted in an “isolation valve closing,” Sheehan said. NRC inspectors were monitoring the company’s investigation, Sheehan added. Talen said Unit 1 shut down at 11:32 a.m. Thursday. Unit 2 was operating safely at full power. The Susquehanna plant is in Salem Township, Luzerne County, about 75 miles northwest of Allentown. It is owned jointly by Susquehanna Nuclear LLC and Allegheny Electric Cooperative Inc.

Source: RSOE EDIS

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