Pilgrim: Transitioning To A Low Capacity Factor Nuclear Plant

Sept 1 update

They wouldn’t let me talk to the Pilgrim inspector. Only the region public affairs guy. Nice conversation with Neil. The unistrut holding up the copper tube pulled out of the concrete with the copper tubing then falling on the main steam line. Its vibration caused the tube to crack or break.

What is a unistrut?   

Aug 27

Good job Pilgrim now at 100% power.

Aug 26

Oh brother, 24 hours and only 82% power level today? Got problems?

Aug 25

 ***Seems to be those knowledgeable with the design say there is little chance it being vibrations. Basically the steam pipes are hard attached to the concrete part of the containment. The vibrations in the main steam lines high up containment with the SRV makes sense. Although plants have had pipe attachments and restraints from the containment to the turbine repeated fail do to the vibration flow.   

What chances do you think they got of a smooth startup and return to 100% do they got. Less than 50/50?

I see Pilgrim started up last night.

Wow, we haven’t seen this all summer. The NE ISO grid price is now about $450 per megawatt hour. I can’t believe Pilgrim did this???

At 4pm it is only 83 degrees in my Hinsdale, NH area? It is 73 degrees in Boston today?   

***This just goes to show how pathetically weak the NRC is with letting Pilgrim get off the hook with prior scrams and enhanced inspections. Oh yea, the NRC fixed them with their heavy hand.   

Officials Investigating Automatic Shutdown at Pilgrim  

PLYMOUTH – An automatic reactor shutdown was triggered at the Pilgrim Nuclear Power Station late Saturday. 

Plant officials, plant-owner Entergy, and the Nuclear Regulatory Commission are investigating the cause of that shutdown. Officials are on-site today.

The Nuclear Regulatory Commission says the shutdown never created a threat to the public. It’s not clear when the plant will be back online. 

This is the third shutdown at the Plymouth plant this year. Pilgrim was under additional oversight by the NRC until the end of June as a result of the two earlier shutdowns. NRC inspectors found that the plant had addressed the areas of weakness responsible for the unplanned shutdowns during winter storms in January.

According to NRC spokesman Neil Sheehan, the NRC is continuing to review an apparent violation that was issued to Pilgrim on May 27. 

That finding involves the maintenance of the plant’s safety relief valves and stems from a special inspection conducted at the site after January’s shutdown.

I wished they disclosed what steam line the MSIV broke from. NRC event report:

REACTOR SCRAM DUE TO A SINGLE MSIV CLOSURE "On Saturday, August 22, 2015, at 1628 [EDT], with the reactor at 100% core thermal power (CTP) the Pilgrim Nuclear Power Station (PNPS) experienced an automatic reactor scram signal due to the rapid closure of one main steam isolation valve (MSIV). Other than the MSIV all other plant systems responded as designed. Plant cooldown is in progress using steam bypass to the main condenser.

"The plant is in hot shutdown. The cause of the MSIV closure is still under investigation. This event has no impact on the health and safety of the public. The licensee has notified the NRC Senior Resident Inspector.

"This notification is being made in accordance with 10 CFR 50.72(b)(2)(iv)(B), 'Any event that results in actuation of the reactor protection system (RPS) when the reactor is critical'.

"Subsequent to the reactor scram the plant experienced the following isolation signals:

- Group 2 Isolation: Miscellaneous containment isolation valves

- Group 6 Isolation: Reactor Water Clean-up

- Reactor Building Isolation Actuation

"This notification is also being made in accordance with 10 CFR 50.72(b)(3)(iv)(A), 'Any event or condition that results in valid actuation of any of the systems listed in paragraph (b)(3)(iv)(B) of this section' (B)(2) 'General containment isolation signals affecting containment isolation valves in more than one system or multiple main steam isolation valves (MSIVs).'"

Plant response was considered normal and the plant is in a stable shutdown / cooldown condition. The license will be notifying the Commonwealth of Massachusetts.

The copper tube makes sense. The problem is, the Safety Relief Valve broke because of abnormal vibrations on the main steam line valves line. The only sense with why these safety grade small copper tubing broke is through excessive vibration.

I request an evaluation on vibrations on all main steam lines and request they install temporary vibration monitors on main steam lines before start-up to detect any abnormal main steam line vibration.

I believe I asked the NRC if Pilgrim had installed Main Steam Line Isolation Valves vibration detectors...the NRC said they didn't require it. I was shocked they didn't.

Are there any associations with broken SRVs and the failed MSIV copper tube... 

Inquiry to begin over Pilgrim nuclear plant’s ‘safe’ shutdown

David L. Ryan/Globe Staff/File

The Pilgrim Nuclear Power Station in Plymouth went into automatic shutdown Saturday.

By Nicole Fleming Globe Correspondent August 23, 2015

The Pilgrim Nuclear Power Station on Cape Cod Bay in Plymouth remains closed Sunday after going into an automatic shutdown Saturday afternoon, according to station and government officials.

“The plant is currently in a safe, stable shutdown condition and there is no impact on the health and safety of the public or plant employees,” said Lauren Burm, a spokeswoman for Entergy Corp., the company that operates Pilgrim, in a statement.

Officials for the Nuclear Regulatory Commission, an independent government agency overseeing the safety of nuclear plants, reiterated Sunday afternoon that there were no safety concerns regarding the state’s only operating nuclear power station.

“There were no complications during the shutdown and no increased risks to plant workers or the public,” said Neil Sheehan, an NRC spokesman.

The reactor and associated systems were cooled down to allow for an investigation into what caused the emergency shutdown, which is also called a scram.

Nuclear reactors use steam to make electricity, operating “like a giant tea kettle, turning water into steam which spins giant turbines that power generators to make electricity,” according to an explanation on Pilgrim’s website.

The shutdown occurred at about 4:30 p.m. Saturday while the reactor was at 100 percent power, triggered by the closure of a single main steam isolation valve, Burm stated, with all other plant systems responding as designed.

‘There were no complications during the shutdown and no increased risks to plant workers.’

Neil Sheehan, Nuclear Regulatory Commission spokesman

The valves “would be used in the event of an accident to halt the flow of steam from the reactor to the turbine building and thereby help ‘isolate’ radioactivity to the containment building surrounding the reactor,” said Sheehan.

A copper tube about a half-inch in diameter, called an air/nitrogen line, broke, triggering the valve closure, said Chip Perkins, a nuclear engineer and the regulatory assurance manager for Entergy. While the repair of the line shouldn’t be that complicated, the plant will do an investigation into what they call “extended circumstances,” followed by other independent investigations.

“Once we find a problem, we go in and look around to see if there are any other problems like it and any other areas where we have similar conditions,” said Perkins.