Millstone: Four Special Inspections Since Aug 2014. Just Junk!

Basically Millstone has had two special inspections within a year and a half…four since Aug 2014. What a wonderful record. Two on their inability to come to terms with maintenance problems on the Turbine Driven Aux feedpump, one on the dual plant trip caused by Dominion’s inability to maintain their switchyard and now on a leaking relief valve at 248 psig and degrees f. Way to go NRC?

Holy smokes 90 minutes. A steam leak like this can cause much grounding of electrical, fire detection and other instrumentation problems.

 The incident, which lasted 90 minutes, qualified as an "unusual event," which is the lowest of four levels of NRC emergency classifications.

I'l bet you they put shutdown cooling on at about 300 psig and the relief valve opened then.

That is a real lot of energy. What does greater than 25 gallons a minute mean? It is a really a lot of dangerous steam in a small room. They were lucky they didn't scald a employee to death.  

Current RCS temperature is 248 degrees F with RCS pressure at 248 psig. The declaration was based on reactor coolant system leakage of greater than 25 gallons per minute.

So how many gallons of steam? I'll bet you the relief discharged directly into room...maybe in the sump. They'd not be much difference?  

"...exceeding 25 gallons per minute [GPM], per EAL BU2, due to a relief valve leaking on the Shutdown Cooling System common header.

Are you going to find simulator fidelity issues here like Pilgrim and River Bend?  

 

Millstone is still in the refueling outage at zero percent power today. Usually they wait till they get back up at power to declare the special inspection. This must be a big deal. 

The special inspection notification today:  

NRC Initiates Special Inspection at Millstone Unit 2 Nuclear Power Plant 

The Nuclear Regulatory Commission has begun a Special Inspection at the Millstone Unit 2 nuclear power plant to review issues associated with an “Unusual Event” declared at the facility on Oct. 4. The two-member team arrived at the Waterford, Conn., plant today to begin the review. 

Operators at the plant declared an “Unusual Event” – the lowest of four levels of emergency classification used by the NRC – at about 9:30 a.m. on Oct. 4. The declaration was based on reactor coolant system leakage of greater than 25 gallons per minute. The leakage came from a relief valve on the plant’s shutdown cooling system, which is used to provide cooling to the reactor when it is out of service. 

The Dominion-owned and operated plant was preparing to enter a refueling and maintenance outage at the time of the event. 

In response to the leakage, the shutdown cooling system was isolated from the reactor coolant system, allowing repairs to be made and the return of the system to operational status. The emergency declaration was terminated at 11 a.m. All of the leakage was contained within other plant systems, as designed. 

After conducting a preliminary assessment of the event, the NRC has determined that it meets the criteria for a Special Inspection. Among other things, the team will review operator response to the event, equipment performance and immediate corrective actions. 

“Our initial review of the event has raised questions regarding operator performance,” NRC Region I Administrator Dan Dorman said. “We have determined that the use of a Special Inspection is appropriate in this case to help the NRC better understand Dominion’s response to the event.” A report documenting the team’s findings will be issued within 45 days after the conclusion of the inspection.

The event notification:

UNUSUAL EVENT DECLARED DUE TO IDENTIFIED RCS LEAKAGE > 25 GPM

At 0932 EDT on 10/4/15, the licensee declared an Unusual Event for identified RCS [Reactor Coolant System] leakage exceeding 25 gallons per minute [GPM], per EAL BU2, due to a relief valve leaking on the Shutdown Cooling System common header. The RCS leakage was within the capacity of the Charging System. At 0954 EDT the RCS leakage was terminated by isolating the Shutdown Cooling System. The cause of the relief valve failure is unknown and under investigation.

The RCS cooldown was terminated and both RCS loops were restored to service for decay heat removal using both Steam Generators and the Main Condenser. Current RCS temperature is 248 degrees F with RCS pressure at 248 psig. All offsite power and EDGs [Emergency Diesel Generators] are available.
The licensee intends to repair the relief valve to resume the RCS cooldown using the shutdown cooling system..

The licensee informed State and local agencies and the NRC Resident Inspector.

Notified DHS SWO, DHS NICC, FEMA, and Nuclear SSA via email.

* * * UPDATE AT 1115 EDT ON 10/04/15 FROM FRED PERKINS TO S. SANDIN * * *

The licensee terminated the Unusual Event at 1100 EDT, based on verification that the RCS leakage was stopped.

The licensee informed State and local agencies and the NRC Resident Inspector.

Notified R1DO (Bower), NRR EO (Morris), and IRD (Gott).

Notified DHS SWO, DHS NICC, FEMA, and Nuclear SSA via email.