Dresden Has Pilgrim's SRV Resonance Vibration Problem?

Note to Nuclear industry: You keep this shit up, we will go back to the bat upside the head philosophy or era in order to protect the politician (from you). 

Dresden NRC Senior

Again, a really technically impressive senior resident and a easy guy to talk to. Basically he talked about all corrective actions coming out the Quad Cities and Dresden since uprate working the electromatic Safety Valves. I chided him these guys are on welfare and need to not trust these guys. There poor as hell! My take, the primary responsibility is to not allow these components to degrade in the first where we don’t know what condition they are in. You all utterly failed in that job and I worry it will happen again and again. I told him the NRC and licensee works for me as a licensed operator. It is your job to provide me always with a pristine environment with no surprises in a transient or accident… without any component degradation or failure.

I told him I am still shocked that the licensee and NRC did not understand the main stream line vibration changes…to demand those sturdy valves were installed prior to the uprate. You primary duty is anticipate problems and fix it before problem are seen…not the primary job today of writing after incident reports on broken safety equipment. You work for me…that is how you got my back. 

In unit 3 he said the big headache is unexplainable high“B” steam line vibrations.

The rudimentary calculations would be: 

2957 megawatt thermal / 2527 = 1.17

That means a 17% power uprate. 

( 1.17) ^2 (squared) = 1.367 

That is possible 36% INCREASE IN vibration

Bottom line to the resident NRC staff: the problem is the NRC doesn't provide you with the proper tools to manage a plant like Dresden. I consider the NRC residents as our front line heroes! NRC Washington DC don’t give you a big enough bat to hit these guys squarely between the eyes and teach you how use force and influence in order to prevent chaos in these plants. 

Basically somewhere in here you shutdown a plant for six months for not doing proper engineering. Once the other plants see that, they will all straighten up on their own accord.   

Oyster Creek NRC Resident 

I just talked to the Oyster Creek senior resident. He was another good NRC senior resident. He says a in-depth inspection is going to be released within days. He say the fix is like Dresden and Quad Cities, more sturdy Electromatic Relief Valves. I said fine, but what caused it? The reliefs seemed to have good reliability through the years and then bam we ran into 2014. The Oyster Creek resident has worked closely with Dresden to develop the new inspection report. He told me to read the inspection. 

He reminded Dresden had another ERV failure.  I am trying to speak to the Dresden resident. He called once and I didn't answer the phone because I was busy. He left me recording he would  call back later today.  

First posted on 2/2/2015; Republished

All you need to know about Dresden: 

Dresden had 15 LERs in 2014.

Had about 6 in 2013.

Maybe 2001, 2003 and 2004 averaged 2 and 3 a year.

working on it!
remember check out Oyster Creeks Electromatic Relief Valve problems?

megalomaniac

Dinosaurnastic

http://articles.chicagotribune.com/2014-03-09/business/ct-exelon-closing-nuclear-plants-0308-biz-20140309_1_quad-cities-plant-byron-plant-exelon

As Exelon threatens to shut nuclear plants, Illinois town fears fallout

Profit eludes Clinton site, 5 others in state for years, Tribune analysis finds

March 09, 2014|By Julie Wernau and Alex Richards, Tribune reporters

Chicago-based Exelon, parent of Commonwealth Edison, and the nation's largest operator of nuclear power plants, said last month that unless market conditions improve, it will announce plant closings by the end of this year.

As recently as mid-2008, competing sources of generation had very high costs relative to nuclear plants, said Travis Miller, director of utilities research at Chicago-based Morningstar. "As those fossil fuel costs came down substantially from those peaks five years ago, nuclear has lost a lot of its cost advantage when you consider the amount of capital investment it requires."
The Tribune analyzed hourly power prices that Exelon's reactors in Illinois received over six years and determined the plants haven't made enough money to cover operating and ongoing capital costs since 2008. Among the newspaper's findings:
Exelon's plant in Clinton, the only one without a second reactor, is in the worst financial shape of the company's Illinois nuclear installations. The plant's power prices plummeted from $42 per megawatt-hour in 2008 to $22 in 2009 and have held below $29 on average each year since. Single-reactor plants like Clinton cost between $45 and $55 per megawatt-hour to operate, according to the NorthBridge Group.
•Exelon's Dresden plant is faring the best of the Illinois plants, but it still isn't profitable. In 2010 and 2011, the plant eked out $33 per megawatt-hour in sales, offset by operating costs ranging between $35 and $40 per megawatt-hour.
•Quad Cities and Byron have been hit the hardest by "negative" price conditions, meaning Exelon paid the operator of the electric grid to take its power. Because nuclear plants operate around the clock, they are continually producing power, and in 2012, the Quad Cities plant was paying the grid operator to take its power 8 percent of the time. In 2010, the Byron plant was paying out 7 percent of the time.


Lets establish some basic facts here.

1) It's the responsibility of the NRC and Exelon to make sure the power unrate doesn't wear out  or impair the Electromatic Relief Valve out or impair the operation of Dresden before the uprate. These are old style Safety Relief Valves.

2)Dresden is under severe financial pressure.

3) Exelon is financial impaired,

4) You know what sounds like crazy, doing a big uprate, then can't afford to uprate the main turbine.

5) Dresden's post EPU vibration level is 10 to 20 lower than Quad City justifying not sturdy ERV...while both plant's
 ERV immediately start.


January 29, 2014: DRESDEN UNITS 2 INSPECTION REPORT 05000237/2014005; 05000249/2014005 AND PRELIMINARY WHITE FINDING 

Failure to Ensure Continued Operability of Unit 3 Electromatic Relief Valve 3–0203–3E Following Implementation of Extended Power Uprate Plant Conditions

If Exelon is incapable of for fulfilling their licencing responsibilities, we pay the NRc to step in and make them comply. So this went through a licence amendment request, why didn't the NRC the NRC catch this? Is their something wrong with the way the NRC does verifying a LAR. It is almost like the NRC pats the licencees on the shoulder, go ahead with the illegal LAR, if the component fails with going to ding with a insignificant violation.

Introduction: A finding preliminarily determined to be of low to moderate safety significance (White) and an associated AV of 10 CFR 50, Appendix B, Criterion III, Design Control, was identified for the licensee’s failure to establish measures to ensure that the ERV actuator for 3–0203–3E remained suitable for operation at EPU power levels prior to fully implementing the Unit 3 EPU in November 2010.

Description: The licensee experienced a failure of the 3E ERV with the reactor shutdown in Mode 5 during surveillance testing in accordance with licensee procedure DOS 0250–07, “Electromatic Relief Valve Testing with the Reactor Depressurized” on November 6, 2014. During this surveillance, operators in the main control room (MCR) manually actuate open the

This is when it broke

ERV’s. When cycling the 3E ERV, MCR operators noted that the valve position indication did not change out of the closed condition, and locally assigned equipment operators heard a click when the demand signal was given but the actuator plunger did not move, therefore the ERV did not reposition open.

The ERV actuator is a solenoid assembly that energizes to reposition the ERV pilot valve. When an open signal is sent to the ERV actuator, its solenoid energizes causing a plunger to travel downward and contact the strike lever on the pilot valve assembly. The plunger causes the ERV pilot valve to mechanically reposition relieving pressure internal to the ERV main valve causing it to open and direct steam from the main steam system to the torus suppression pool. The ERVs serve as a component of the automatic depressurization system (ADS) designed to depressurize the RCS during certain loss of coolant accidents in order for the low pressure coolant injection and core spray systems to be able to inject make-up water to the RCS. In addition, the ERVs provide RCS over pressure protection in order to minimize the likelihood that the main steam safety valve will have to actuate to protect the RCS from over pressurization.

The licensee performed an Equipment Apparent Cause Evaluation (EACE 2407705) and determined the apparent cause of the ERV failure to be that the actuator design is susceptible to vibration induced wear in conjunction with the increased vibration on the Unit 3 ‘B’ main steam line near the 3E ERV. The increased vibration is associated with EPU steam flows as a result of

So me it sounds like it was the increased vibration EPU and some other mysterious forces.

full implementation of EPU plant conditions. Specifically, the actuator design installed on Unit 3 ERVs at the time of the event allowed for excessive movement of the solenoid plunger when vibrated. This excess movement resulted in friction wear on the solenoid plunger guides, spring guides, and springs. As a result of the wear on the spring and plunger guides, mechanical binding of the actuator occurred preventing the plunger from physically operating the ERV.

The licensee received a license amendment from the NRC to operate at EPU conditions

There is the LAR?

increasing licensed core rated thermal power (RTP) from 2527 MWth to 2957 MWth starting with fuel cycle D3C18 which went into effect following refueling outage D3R17 in the fourth quarter of 2002. Due to limitations of the main generator, Dresden operated at higher thermal output power but was not able to consistently operate at RTP conditions. Full RTP was achieved only for short durations in the warmer summer months when plant efficiency was poorest and full thermal power resulted in a lower steam/electrical plant output which was within the capacity of the main generator. During this time, Dresden and Quad Cities Generating Station, which also received a licensee amendment to operate at EPU power levels,

Quad cities got actuator damage from violation. The question yet to be answered is at what level of vibration does damage begin.

experienced steam dryer cracking. Quad Cities Generating Station also experienced vibration damage and failures of ERV actuators. As a result of this operating experience regarding the ERV failures at Quad Cities, the licensee performed main steam line vibration recording on Dresden Unit 3 at 2851 MWth on December 29, 2003, and 2951 MWth on October 8, 2004.

Ok, the base line vibration reading at the new max power. What is causing the high vibration QC?

The results indicated that steam line vibrations on Unit 3 were significantly lower (10–20 times)

This is so unethical...what the hell was the reading at Dresden. This is basically engineering malpractice by Dresden assuming there was a relation between the violation at Quad Cities and Dresden. Did the NRC eyeball the both the vibration reading of Dresden and  Quad Cities.

Something is really fishy here, Dresden says Quad City’s vibration is 10 to 20 times higher than Dresden…that justified not putting in sturdy reliefs like QC right after EPU. QC has problems with damaged ERVs right after the EPU with high vibration levels, while when Dresden’s finally goes into EPU with low vibrations, they immediately get ERV damage just like QC. We really don’t know the magnitude of the change of vibration and how it relates to power changes and valve damage. The engineers should know relative vibration levels and damage.

in magnitude than those experienced at Quad Cities and the licensee used engineering judgment to conclude that there was no expected increase in wear rate of the internal actuator components at Dresden.

On April 20, 2007, the licensee submitted a letter to the NRC entitled, “Request for Acceptance for Continuous Extended Power Uprate Operation.” This letter chronicled corrective actions taken at Dresden and Quad Cities Nuclear Plants with regards to steam line vibrations and committed to performing inspections of ERV actuators during the next Dresden refueling outage. Of note, was the installation of ERV hardened actuators at Quad Cities Nuclear Plant to address vibration induced failures of ERVs experienced immediately following implementation of EPU. The NRC responded to this letter on June 11, 2007, acknowledging

Quad Cities has EVRs failures right after EPU.

the corrective actions and inspection that had been completed at both sites and stated that the agency had no further objection to continuous operation at full licensed thermal power of 2957 MWth and that the licensee would be expected to fulfill the commitments made in their April 20, 2007 letter.

During refueling outage D3R21 in 2010, the licensee performed a main generator rewind on Unit 3 thus permitting the main generator to supply electrical output power sufficient enough for the reactor to operate at RTP during the entire operating cycle. This upgrade meant that the main steam lines would be operating at full steam flow during the entire two year operating

Did the Vibration at QC change from 203 to 2010?

cycle and would be, along with attached components including the ERVs, subject to higher vibrations for a significantly greater time period.

The inspectors reviewed the licensee’s inspection and maintenance records of the Unit 3 ERV actuators dating back to 2004. Following required surveillance testing of the ERVs each refueling outage, the licensee performed internal inspections of the ERV actuators to identify any components that were degrading due to vibration induced wear. During the time period between 2004 and 2010, the licensee experienced no surveillance failures and noted only minor vibration induced wear of ERV actuator internal components. The licensee proactively replaced all internal components showing wear following these inspections. During the surveillance testing and inspections that have occurred in the refueling outages following the two operating cycles ending in 2012 and 2014 since the generator rewind, the licensee has experienced two failures

Just at in Quad Cities, the Dresden ERVs failed right after full power operation.

of the 3–0203–3E, 3E, ERV, and noted significant wear damage to the actuator internals of the 3B and 3E ERV with notable but less significant wear to the 3C ERV. During refueling outage D3R22 in 2012, following multiple successful operations in the course of surveillance testing the 3E ERV actuator became mechanically bound due to significant wear induced damage and a loose bolt in the spring guide mechanism. As the ERV had performed successfully prior to that testing, the failure was considered to have occurred at the time of discovery and the licensee determined that the ERV would have performed its function during the previous cycle. The

How do you know it wouldn't have failed last operating period... maybe the failure is intermittent. Would the conservative judgement come to the conclusion to say it failed half way into the last operating period.

licensee made the decision to replace the actuator with a similar model actuator even though the wear degradation was significant as they planned to replace all four ERV actuators with the hardened design utilized at Quad Cities Generating Station since 2007 during the next refueling outage in 2014.

***

Doesn't that seem strange, four nuclear plants all of a sudden coming up with Vibration problem damaging safety relief valve or like.

All caused by vibrations. 

*Dresden...uprate related, but vibrations levels 10 to 20 times lower than Quad Cities 

Pilgrim...change in specs (reduction in quality) 

*Quad Cities...uprate related 

Oyster Creek...mysterious and no change in specs and or power

Plants with similar Dresser EMRVs: Nine Mile Point, Quad Cities, and Dresden.
*involved in EPU 

You get it, Dresden says the damage is related to uprate, Oyster Creek had no uprate, now sure what caused it. 

Different manufacturers Dressor Target Rock

Oyster Creek  

PART-21 REPORT - ELECTROMATIC RELIEF VALVE EXCESSIVE WEAR
The following report was received via e-mail: "This is a non-emergency notification from Oyster Creek Nuclear Generating Station (OCNGS) required under 10 CFR PART 21 concerning the design of Electromatic Relief Valve (EMRV) actuators.

"On June 20, 2014, during as-found bench (stroke) testing of the EMRV actuators removed from the plant during refueling outage 1 R24 (October 2012), two of five EMRV actuators failed to operate. Subsequent inspection of these actuators found unexpected wear of the posts (grooves approximately 1/2" from the top), springs (thinned and broken at the top), and guides (grooves inside), with one spring having a piece axially wedged between the post and the guide.

"The root cause of this failure was determined to be the inadequate design of the EMRV actuators in that when placed in an environment where the actuator is subject to the vibration associated with plant operation, the allowed installation tolerances between posts and guides can create a condition where the springs can jam the actuator plunger assembly by wedging between the guides and the posts. If the EMRV actuators are set up in a condition where the posts are not optimally aligned, preferential wear of the post is observed due to interaction of the post, spring, and guide. Additionally, the vendor guidance for refurbishment of the EMRV actuator does not provide the necessary acceptance criteria for alignment of the posts to guides to ensure that the springs, posts, and guides do not interact in a way that causes preferential wear of the post allowing the jamming mechanism to exist. "By OCNGS process, the EMRV actuators are refurbished with new springs, posts, guides, and microswitches every 24 months during refueling outages due to the known wear of these parts. The actuator inspection/refurbishment frequency of 24 months exceeds the manufacturer's (i.e., Dresser Industries)
V
09/25/2014 U.S. Nuclear Regulatory Commission Operations Center Event Report Page 2
recommended frequency of 36 months (per Vendor Manual VM-OC-0030, Installation and Maintenance Manual for Electromatic Relief Valves, Revision 1, Section VII, Ref. 4.5). In addition, in 2008, the station implemented the manufacturer's recommended material changes intended to minimize part wear, and prevent potential actuator failures.

It doesn't make since: why does it fail in 2014, but not in prior year.

Root Cause: The root cause of this failure was determined to be the inadequate design of the EMRV actuators in that when placed in an environment where the actuator is subject to the vibration associated with plant operation, the allowed installation tolerances between posts and guides can create a condition where the springs can jam the actuator plunger assembly by wedging between the guides and the posts. If the EMRV actuators are set up in a condition where the posts are not optimally aligned, preferential wear of the post is observed due to interaction of the post, spring, and guide. Additionally, the vendor guidance for refurbishment of the EMRV actuator does not provide the necessary acceptance criteria for alignment of the posts to guides to ensure that the springs, posts, and guides do not interact in a way that causes preferential wear of the post allowing the jamming mechanism to exist.