Sequoyah Fried Two Worker...

This indicates something is deeply wrong with management. Prolonged death by electrocution is a horrible way.  

Power Reactor	Event Number: 53270
Facility: SEQUOYAH Region: 2 State: TN Unit: [1] [2] [ ] RX Type: [1] W-4-LP,[2] W-4-LP NRC Notified By: CAL ATCHLEY HQ OPS Officer: JEFF HERRERA	Notification Date: 03/19/2018 Notification Time: 02:27 [ET] Event Date: 03/19/2018 Event Time: 00:30 [EDT] Last Update Date: 03/19/2018
Emergency Class: NON EMERGENCY 10 CFR Section: 50.72(b)(2)(xi) - OFFSITE NOTIFICATION	Person (Organization): REBECCA NEASE (R2DO) CHRIS MILLER (NRR) JEFFERY GRANT (IRD)

Unit	SCRAM Code	RX CRIT	Initial PWR	Initial RX Mode	Current PWR	Current RX Mode
1	N	Y	100	Power Operation	100	Power Operation
2	N	Y	100	Power Operation	100	Power Operation

Event Text

TWO CONTRACTORS INJURED BY ARC FLASH "On 3/16/2018 at approximately 1630 EST, an industrial safety accident occurred at Sequoyah Nuclear Plant that involved an Arc Flash injury of two contract employees. While performing work near a non safety related 6.9kV electrical bus, an arc occurred injuring the two employees. Both personnel were transported to an offsite medical facility for treatment. Neither were contaminated. "The cause of the arc flash is not understood at this time, an accident investigation has been initiated by TVA. The SQN [Sequoyah Nuclear] NRC Senior Resident Inspector has been notified. No safety related systems required to establish or maintain safe shutdown were affected. Both Unit 1 and 2 remain at 100 [percent] power. "TVA has received and responded to media inquiries concerning this event. As a result, this event is considered reportable under 10CFR50.72(b)(2)(xi).

Junk Plant Pilgrim: Is An Terrorist Attack in Progress

Two suspicious incidents just outside the plant in six hours. Or are terrorist planning a attack. It sounds like the community around the plant are nervous...  

March 5 police report

8:05 a.m.: Suspicious activity was reported on Bradstreete Crossing.

2:06 p.m.: Suspicious activity was reported at Pilgrim Nuclear/Entergy on Rocky Hill Road.

Junk Plant Pilgrim: Could Cape Cod Be Evacuated After The Current Blizzard

Update

NRC resident seem extremely rushed for time when I called. Said the NRC is trying to deal with the loop. It seems strange this busyness so many days after the LOOP and reconnected to the grid. She said the LOOP went pretty well. She said it was the switchyard that caused it and it was Entergy's gear.  

Pilgrim has had massive historic problems with the grid around their Plant. Its trips them many times and isolates them from outside power. Though shutdown this blizzard, they had very serious grid problems this blizzard.

Watching Pilgrim over the years, you can clearly see both Entergy and the grid owners haven't kept up with maintenance. These insufficient funding of maintenance and updating equipment issues have massively impacted Pilgrim's reliability and safety.  

Excerpts from the most Current Blizzard:   

“It’s been a pretty crazy couple of weeks for everyone down here on the Cape and across the Commonwealth,” he said.

Secretary of Energy and Environmental Affairs Matthew Beaton said the region has been dealing with an, “an unprecedented volume of outages in recent weeks.”

Several of the state representatives said in addition to the problem with the power failures, many Cape Codders lost cell service, specifically AT&T customers.

Hunt, who represents portions of the Upper Cape and Plymouth, said we can’t accept the excuse that being an ocean-side community leads to more outages.,

“You have to build your utility to withstand the conditions wherever your utility is,” Hunt said. 

“It does make me wonder if there’s probably a larger conversation we should be having about trees,” Baker said.

“The biggest question I have that needs to be answered is what is the state of the utility and electric supply out there with old telephone poles, old transformers and other things that have not been updated,” Cyr told the Herald. “When you have a stress like this — when it’s older equipment — it’s not as resilient.”

Cyr said in addition to keeping an eye on Eversource Energy’s power restoration efforts, he wants to know what is being done now to make sure the electric system stands up better to the next storm, especially with the expectation that the weather could grow worse as the climate changes. 

“Why do we have this failure?” he asked. “I think that’s what we are going to be working at. We have to have an electric supply system that can stand up in the environment we have out there.”

Eversource spokesman Mike Durand said the company has a comprehensive tree-trimming program and equipment upgrade plan.

“The reason for the devastation that we have seen in this storm and previous storms is the severe weather” that brought a foot of snow and hurricane-force winds to the Cape, Durand said.

Junk Plant Grand Gulf: BIG NEWS!!!

Grand Gulf has been up to 100% power for two weeks :)

Vogtle 3&4: Statement Of NRC on Registered Professional Engineers

Crutchley, Julie	Mar 13 (1 day ago)
to me, Sara, Sarenee, Sean, Stella, Dori

Dear Mr. Mulligan:

The U.S. Nuclear Regulatory Commission (NRC) has completed its review of the concerns you raised relating to Westinghouse and Vogtle Units 3 and 4.  Our letter describing our review and conclusions is attached.  Please acknowledge your receipt of this message and its attachment via return email or phone call.  We would like to keep a copy of your receipt for our records.

Thank you for bringing these matters to our attention.  If you have any questions or comments on the attached letter, please contact a member of the NRC Headquarters Allegations Team via our group email, HQ_Allegations@nrc.gov, or contact us individually:

·         Ms. Dori Willis, Senior Office Allegation Coordinator (Dori.Willis@nrc.gov), 301-287-9423

·         Mr. Sean Meighan, Office Allegation Coordinator (Sean.Meighan@nrc.gov), 301-287-9094

·         Ms. Sarenee Hawkins, Office Allegation Coordinator (Sarenee.Hawkins@nrc.gov) , 301-287-9292

·         Ms. Sara Bernal-Taylor, Allegation Specialist (Sara.Bernal-Taylor@nrc.gov), 301-287-9296

·         Ms. Stella Opara, Allegation Specialist (Stella.Opara@nrc.gov), 301-287-9286

Regards,

Julie Crutchley

I wonder if this is a wave off in the FBI and others are investigating this? 

STATEMENT OF CONCERN ALLEGATION NO. NRO-2017-A-0015

CONCERN
 You received a call from an engineer who works at Vogtle.  This engineer claimed that he has “the same problem as what is going on at V.C. Summer,” which is that non-licensed engineers are signing off on safety-related diagrams/paperwork that should be signed off by licensed engineers.

NRC Response:
 In order to evaluate the concern, the NRC staff (1) evaluated the pertinent regulations; (2) reviewed the associated Post and Courier news article, the letter from the National Society of Professional Engineers (NSPEs), and the Westinghouse Electric Company LLC’s (WEC’s) legal opinion on the use of Registered Professional Engineers (RPEs); (3) reviewed specific drawings that the reporter of the news article believed required a RPE’s approval; (4) compiled a list of American Society of Mechanical Engineers (ASME) Code requirements specifying RPE review of design reports and design specifications; (5) reviewed Regional and Vendor inspection reports associated with design reports and design specifications; (6) interviewed a sample of inspectors on the practice of ensuring whether a design report or design specification has been approved by a RPE; (7) reviewed excerpts from the State of South Carolina’s requirements regarding a utility’s use of RPEs; and (8) reviewed NRC guidance in inspection procedures (IPs) to determine if review of RPE documentation approval and personnel qualification are adequately addressed.

Regarding regulatory requirements, Criterion II, “Quality Assurance Program,” of Appendix B, “Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants,” to Title 10 of the Code of Federal Regulations (10 CFR) Part 50, “Domestic Licensing of Production and Utilization Facilities,” states in part, “The program shall provide for indoctrination and training of personnel performing activities affecting quality as necessary to assure that suitable proficiency is achieved and maintained.”  This regulation would apply to engineers involved in the development of the AP1000 nuclear power plant safety-related design activities.  The NRC’s inspectors routinely assess the training and qualification of engineers.  

 The staff also reviewed the ASME Code to determine when a RPE’s approval is required to be verified by the NRC.  The AP1000 Final Safety Analysis Report, Chapter 5.2.1.1, requires compliance with 10 CFR 50.55a, “Codes and standards.”  In 10 CFR 50.55a(a)(1)(i), all ASME Boiler and Pressure Vessel Code, Section III additions and addenda are incorporated by reference.  10 CFR 50.55a(b)(1) places certain conditions on Section III of the Code, but none of these regulatory conditions are associated with RPEs. 

 As an example, NRC staff would be required under 10 CFR 50.55a to verify a RPE’s approval on an ASME Code Form N5 associated with components manufactured to Code requirements.  This form is required to be signed by a RPE and is reviewed by the NRC as part of its inspection of the Inspections, Tests, Analyses, and Acceptance Criteria (ITAAC) related to that Code component. 

 Regional and Vendor inspectors only look for RPE approval when required to do so by applicable ASME Code requirements, but normally do not document it in an inspection report unless an associated issue is identified.  The associated Regional and Vendor related inspection procedures do not specifically require the NRC inspector to identify whether a design report or design

Is the NRC telling me we got no problem with RPEs because we don't inspect none qualified RPEs.

specification has been approved by a RPE.2  However, the NRC staff did identify one integrated inspection report (ADAMS Accession No. ML17226A0343) which documented in the Inspection Scope that the inspectors reviewed the qualification records for the RPEs that developed the squib valve and piping design specifications.  There was no further discussion as no qualification records issues were identified.  

With regards to the Post and Courier article, the NRC noted that information used to support the author’s position in the article did not state that WEC was using unlicensed or unqualified engineers.  The documents referenced by the reporter focused on the fact that WEC was not requiring a RPE’s approval of certain documents.  However, based on its review, the NRC staff concluded that not all documents need a RPE’s approval.  The specific drawings relied upon for the news article are examples of documents not requiring a RPE’s approval to meet NRC’s requirements.

In addition, when NRC inspections are performed, it is routine to review the qualifications of individuals performing the work.  Also, NRC inspectors often interview personnel in detail on specific work being performed.  These interviews ensure personnel are knowledgeable in their tasks.  There was no indication from the NRC inspection reports that unqualified individuals from WEC or its contractors were involved in the performance of work related to the AP1000 design.

Based on the NRC staff’s review, the NRC staff concluded that (1) there was no evidence of inspection report findings for unqualified personnel preparing design documents, and (2) design reports and design specifications that were required by NRC regulations to have RPE approval did so.  However, because the State of Georgia also has requirements related to professional licensure, you may wish to contact the Georgia Board of Professional Engineers and Land Surveyors directly regarding your concern (http://sos.ga.gov/index.php/licensing/plb/22). 

As stated in our cover memo, we feel that our actions in this matter have been responsive to your concern and plan no further action.   Thank you for contacting the NRC. 

                                                 1 The ITAAC identified in the combined license are those inspections, tests, analyses, and acceptance criteria necessary and sufficient, when successfully completed by the licensee, to provide reasonable assurance that the facility has been constructed and will operate in conformity with the combined license, the provisions of the Atomic Energy Act, as amended, and the Nuclear Regulatory Commission’s rules and regulations. 2 The NRC staff is currently evaluating the value of adding a specific step in NRC inspection procedure(s) that ensures a RPE has appropriately approved the document (if required by the applicable ASME Code) when inspectors are reviewing design reports and design specification documents. 3 Public documents can be found on the NRC’s Agencywide Documents Management System (ADAMS) at https://www.nrc.gov/reading-rm/adams.html.

More Fleet Wide Ethics Training for Entergy: History Shows It Don't Work

Entergy has had hundreds of falsification and other ethical problems over recent years ending in Confirmatory Orders demanding fleet wide ethical training.  Fleet wide ethical training and scapegoating the little guys has been proven not to work. We need a investigation on is ethics training effective.

NRC Issues Confirmatory Order to Entergy  

The Nuclear Regulatory Commission has issued a Confirmatory Order to Entergy Nuclear Operations, Inc., and Entergy Operations, Inc., documenting actions they have agreed to take to implement programs designed to prevent willful misconduct at their fleet of seven operating nuclear power plants. 

As a result of investigations at the Grand Gulf nuclear power plant in Port Gibson, Miss., Entergy identified that (1) an examination proctor deliberately compromised examinations by providing inappropriate assistance to trainees; (2) workers did not perform required rounds to check equipment and plant conditions; and (3) workers deliberately provided inaccurate documentation indicating they had done so. Three apparent violations of NRC requirements are described in a Nov. 20, 2017, inspection report.  

Entergy requested the Alternative Dispute Resolution process with the NRC to discuss corrective actions. The process uses a neutral mediator with no decision-making authority to assist the NRC and its licensees in coming to an agreement.  Following a meeting on Feb. 6 with Entergy officials, the NRC issued a Confirmatory Order documenting actions the company agreed to take. In addition to Grand Gulf, the Entergy fleet includes Arkansas Nuclear One in Russellville, Ark., Indian Point 2 and 3 in Buchanan, N.Y., Palisades in Covert, Mich., Pilgrim in Plymouth, Mass., River Bend in St. Francisville, La., and Waterford in Killona, La.
 

Junk Plant Pilgrim: Leaking Feedwater Heaters And Another Total Loss Of Offsite Power

That 23 line is interesting. It is piss ass small line and extremely unreliable. But it plays a disproportional role in any violation levels if it stays operational. Of course, if the plant was operational, they would have had another hard trip.

The industry and NRC basically believes a plant at shutdown is more risky than at power. So they might be required to shutdown, the utilities will justify staying at power on it more risky to be shutdown.   

Facility: PILGRIM Region: 1 State: MA Unit: [1] [ ] [ ] RX Type: [1] GE-3 NRC Notified By: MICHAEL HETTWER HQ OPS Officer: DONG HWA PARK	Notification Date: 03/13/2018 Notification Time: 15:54 [ET] Event Date: 03/13/2018 Event Time: 10:00 [EDT] Last Update Date: 03/13/2018
Emergency Class: NON EMERGENCY 10 CFR Section: 50.72(b)(3)(v)(B) - POT RHR INOP	Person (Organization): MARC FERDAS (R1DO) JEFFERY GRANT (IRD)

Unit	SCRAM Code	RX CRIT	Initial PWR	Initial RX Mode	Current PWR	Current RX Mode
1	N	N	0	Cold Shutdown	0	Cold Shutdown

Event Text

OFF-SITE POWER UNAVAILABLE DUE TO WINTER STORM "On March 13, 2018 at 1000 hours [EDT], with the reactor in Cold Shutdown condition, both 345kV incoming power lines and 23 kV Shutdown Transformer became unavailable during the Northeast winter storm. Per procedures, the emergency on-site emergency power supplies (Emergency Diesel Generators) were running and providing power to essential systems. In addition, the back-up Diesel Air Compressor was in service and one Reactor Protection System bus was on the back-up power supply prior to the loss. "With both 345kV incoming power lines and 23 kV Shutdown Transformer unavailable, Pilgrim Nuclear Power Station procedures direct a report be made to the NRC per the requirements of Title 10 Code of Federal Regulations 50.72(b)(3)(v), any event that could have prevented the fulfillment of the safety function. No actual loss of safety function has occurred since the on-site emergency power supplies are maintaining the reactor in a safe shutdown condition and removing residual heat. "The loss of incoming power is under investigation. "This event had no impact on the health and/or safety of the public. "The NRC Resident Inspector has been notified."

PSEG Starving Funding For Troubled Hope Creek and Salem

PSEG Canceling Nuclear Plant Spending Due to Stalled Bailout 

The state's biggest utility says it's canceling funding for capital projects at a nuclear plant because of a stalled legislative effort to financially rescue the state's nuclear industry.

March 2, 2018, at 2:49 p.m.

PSEG, Exelon cancel capital projects at Salem nuke after legislation stalls

Public Service Enterprise Group and Exelon Corp. have axed multiple capital projects at their jointly-owned Salem nuclear plant after the New Jersey legislature failed to pass a bill to support the state's nuclear generation.

The bill would have supported PSEG's nuclear plants but the legislation was shelved in the Senate. The subsidies would have added about $350 million annually over 10 years, to the plants' revenue

The spending would have included New Jersey gets about 40% of its electricity from nuclear generation, but owners of the state's plants now say they will not make further investments beyond requirements from the Nuclear Regulatory Commission and other regulations. 

The decision means PSEG will stop working to make the plants more efficient and reliable. NJ.com frames it as a "threat" from generation owners of "dirtier air, higher bills," if subsidies are not provided.

In a Form 8-K filed with the U.S. Securities and Exchange Commission, PSEG said that "funding of these projects may be restored when and if legislation is enacted in New Jersey that sufficiently values the attributes of nuclear generation and Salem benefits from such legislation."…

The bill included both efficiency and solar initiatives, along with hundreds of millions in support for nuclear

The Scale Of The Problem in A Million Components System: SRV

If this is how they treat all the components in their plants, they are going to be overrun with problems.

UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF NUCLEAR REACTOR REGULATION WASHINGTON, DC  20555-0001

February 26, 2018

NRC INFORMATION NOTICE 2018-02: TESTING AND OPERATIONS-INDUCED DEGRADATION OF 3-STAGE TARGET ROCK SAFETY RELIEF VALVES 

ADDRESSEES
 All holders of an operating license or construction permit for a nuclear power reactor under Title 10 of the Code of Federal Regulations (10 CFR) Part 50, “Domestic Licensing of Production and Utilization Facilities,” except those that have permanently ceased operations and have certified that fuel has been permanently removed from the reactor vessel.

All holders of and applicants for a power reactor early site permit, combined license, standard design certification, or manufacturing license under 10 CFR Part 52, “Licenses, Certifications, and Approvals for Nuclear Power Plants.”  All applicants for a standard design certification, including such applicants after initial issuance of a design certification rule.  

 PURPOSE
 The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice (IN) to make addressees aware of recent operating experience related to Target Rock Model 0867F 3-stage safety relief valves (SRVs).  Operating experience has shown that limited flow testing of these valves can result in damage to internal valve components.  This damage can be exacerbated when the valves are re-installed in the plant following testing and subjected to normal plant operating conditions, including steam flow-induced vibrations.  The resultant internal damage has affected valve operability at low steam pressure.  It is expected that addressees will review the information for applicability to their facilities and consider actions, as appropriate, to avoid similar problems.  Suggestions contained in this IN are not NRC requirements.  Therefore, no specific action or written response is required.  

DESCRIPTION OF CIRCUMSTANCES
 Pilgrim Nuclear Power Station

On February 8, 2013, and January 27, 2015, severe winter storms caused loss of offsite power (LOOP) events at Pilgrim Nuclear Power Station (Pilgrim).  These LOOP events resulted in complicated reactor trips, with operators using various systems to lower plant pressure.  In each event, operators noted an unexpected plant response from one of the plant’s four main steam SRVs (Target Rock Model 0867F 3-stage valves) while using the valves to reduce pressure.  During the 2013 event, the “A” SRV did not properly open when it was manually actuated at low plant pressure (i.e., below 300 psig).  Similarly, during the 2015 event, the “C” SRV did not properly open when manually actuated at low plant pressure.  In each case, operators were able to control plant pressure by manually cycling the “B” and “D” SRVs.  

IN 2018-02 Page 2 of 8

Subsequent to the plant reaching cold shutdown following the 2015 event, the licensee removed SRVs “A” and “C” from the plant and sent them—along with a third valve which had been removed from the plant in 2013—to an offsite testing facility for limited flow testing.  The valves were replaced with spare Model 0867F SRVs, and the plant restarted on February 8, 2015.  During limited flow testing at the offsite test facility, the valves consistently opened when exposed to steam pressure at the lift setpoint (approximately 1100 psig) but did not fully close.  The valves were disassembled to allow inspection of the main stage internal components.  This inspection revealed: (1) damage to the threaded connection between the valve stem and the main piston caused by axial displacement of the main piston; (2) fretting damage to the walls of the main cylinder caused by impingement of the main piston rings; (3) loss of torque on the lock nut and deformation of its locking tab; and (4) shortening of the free height of the main valve spring.  The damaged threads and axial displacement of the main piston created a gap between the stem and piston shoulders, allowing the piston to wobble and/or rotate within the cylinder.  During operation, plant vibrations caused the rings on the loose piston to fret against and eventually wear grooves in the walls of the main cylinder.  These grooves affected piston movement and valve operation at low plant pressure during the 2013 and 2015 Pilgrim events.  On March 16, 2015, Curtiss Wright, parent company of Target Rock, issued a report in accordance with 10 CFR Part 21, “Reporting of Defects and Noncompliance” (Part 21), indicating that Model 0867F 3-stage SRVs are susceptible to internal damage that is caused by limited flow testing (Agencywide Document and Management System (ADAMS) Accession No. ML15077A422). 

The NRC chartered a special inspection team in February 2015 to evaluate the licensee’s performance in response to the LOOP event on January 27, 2015.  Following the inspection, NRC staff issued a finding of low to moderate (White) significance for the licensee’s failure to take appropriate corrective actions for a significant condition adverse to quality associated with the “A” SRV during the 2013 LOOP.  The licensee’s failure to take corrective action to preclude repetition resulted in the failure of the “C” SRV during the January 27, 2015, LOOP event.  The NRC staff subsequently published a special inspection report on May 27, 2015 (ADAMS Accession No. ML15147A412).  On September 1, 2015, the NRC staff issued the final determination and a notice of violation to Pilgrim (ADAMS Accession No. ML15230A217).  

During an April 2015 refueling outage, Pilgrim replaced all four of their Model 0867F 3-stage SRVs with Model 7567F 2-stage Target Rock SRVs.  Curtiss Wright issued interim 10 CFR Part 21 reports for Model 0867F SRVs on May 1, 2015 (ADAMS Accession No. ML15134A017), and June 30, 2015 (ADAMS Accession No. ML15187A172).  In these reports, the vendor described how valve internals could be damaged by excessive velocities and impact forces resulting from limited flow testing.  In the June 2015 report, Target Rock described the root causes of internal valve damage, along with its plan for redesigning the valve and its testing requirements in order to limit future testing and operations-induced damage.  Target Rock also indicated that three other nuclear plants at two sites had Model 0867F 3-stage SRVs installed.  The two facilities are the Edwin I. Hatch Nuclear Plant (Hatch), Units 1 and 2, with 11 Model 0867F valves installed in each unit, and the James A. Fitzpatrick Nuclear Power Plant (Fitzpatrick), with three Model 0867F valves installed out of a total of 11 SRVs.

Edwin I. Hatch Nuclear Plant, Units 1 and 2

During a February 2016 refueling outage, Hatch, Unit 1, removed its 11 3-stage SRVs for lift setpoint testing required under technical specification surveillance requirement 3.4.3.1 and the licensee’s inservice testing program.  The valves were tested at the NWS Technologies testing facility on March 30, 2016.  All of the valves properly opened during limited flow testing, but three of the 11 valves failed to properly close following their second cycling on the test stand.  

Two of the three valves that failed to properly close were disassembled, at which time inspectors noted severe internal degradation similar to that found in the SRVs removed and tested by Pilgrim.  The licensee for Hatch contracted an independent engineering firm to evaluate any impact of the damage on valve operability.  The engineering analysis concluded that the potential for valve binding in the open direction was low despite the damage noted in the Hatch, Unit 1, SRVs.  The analysis noted that the fretting wear grooves created by the main piston rings in the main guides of the Hatch, Unit 1, valves were not as steep and deep as those in the Pilgrim valves.  Based on the valve condition and analysis, the licensee determined that the Hatch, Unit 1, SRVs would have been able to perform their design function to open and close over their operational range (down to 150 psig) when installed in the plant, and that the SRVs still installed in Hatch, Unit 2, were operable but in a degraded/nonconforming condition due to the potential for in-service vibration wear.  

The NRC dispatched a special inspection team to Hatch on April 4, 2016.  The team reviewed all aspects of the Hatch operating experience, as well as the licensee’s rationale for the actions it took following review of the Pilgrim events and the vendor’s Part 21 reports.  The NRC inspectors identified no significant performance deficiencies.  Hatch Unit 2 performed a six day mid-cycle maintenance shutdown on May 21, 2016, (14 months into their 24-month operating cycle) to replace, test, and inspect the 11 SRVs.  Both Hatch Units 1 and 2 were returned to operation with refurbished 3-stage Target Rock SRVs that had undergone the vendor recommended modified testing and inspection requirements discussed in the June 30, 2015, Part 21 interim report.  This included removing the requirement to perform a final limited flow cycling of the valve upon reassembly and checking installed valves for evidence of de-shouldering by measuring the gap between the stem and main piston shoulders.  The special inspection report was published on June 10, 2016 (ADAMS Accession No. ML16162A631).

James A. Fitzpatrick Nuclear Power Plant

The licensee for Fitzpatrick removed two of its three Model 0867F 3-stage Target Rock SRVs in June and July of 2016.  One of these valves exhibited degradation similar to that seen at Pilgrim and Hatch, although the fretting wear in the main cylinder was not as severe.  The third 3-stage SRV was replaced in January 2017 and did not exhibit any degradation similar to Pilgrim and Hatch. All three 3-stage SRVs were replaced with 2-stage Target Rock SRVs.

Vendor Corrective Actions

In its June 30, 2015, interim Part 21 report, Target Rock recommended that licensees with Model 0867F 3-stage SRVs installed in their plants assess the valves for the potential of fretting-induced damage and inspect valves as needed.  The impacted licensees (Hatch and Fitzpatrick) responded as described above.  The interim Part 21 report also recommended a revised method for performing limited flow testing on Model 0867F 3-stage SRVs intended for installation at a plant.  The revised method involved additional verifications of the integrity of valve internals following limited flow valve cycling.  Valves are to be checked for thread damage, stem to piston shoulder gap, main spring height, and lock nut torque.  Following satisfactory inspection and retorqueing of the valve internals, the valve can be leak checked, then reinstalled in the plant without the need to cycle the valve again via limited flow testing.  Much of the previous valve damage that led to operational challenges was initiated by this final valve cycling  prior to installation, which could cause the main piston and lock nut to lose torque and become loose on the stem.  Valves were being reinstalled in this condition without any further inspection, creating the conditions for fretting-induced damage to the main cylinder wall.

On February 3, 2017, Target Rock issued a final Part 21 report (ADAMS Accession No. ML17039A569) to inform its customers of design changes to the Model 0867F 3-stage  SRV.  Target Rock evaluated the effectiveness of the changes during limited and full-flow  valve testing between August and November of 2016.  Target Rock recommends this new design as a long-term solution to all utilities that currently have installed or plan to install Model 0867F 3-stage SRVs in their plants. 

 BACKGROUND  

 Valve Design and Actuation

Figure 1 of this document shows a Target Rock Model 0867F 3-stage SRV in the closed position.  Additional arrows and labels have been added to show location of the lock nut, lower piston ring, stem shoulder, and gagging device.

Figure 1:  Target Rock Model 0867F 3-Stage SRV

When installed in the plant, the SRV actuates in the pressure relief mode by sensing system pressure at the pilot valve.  When pressure reaches the valve setpoint, the metal sensing bellows expands against the pilot preload spring and opens the pilot valve.  This allows steam from inside the bellows to act on top of the second stage piston.  The steam pressure causes the second stage piston to compress the second stage preload spring, which unseats the second stage disc.  This relieves steam pressure from the top of the main piston through a vent path to the SRV outlet.  When pressure is relieved from the top of the main piston, system pressure acting on the underside of the piston through orifices drilled in the main guide is enough to overcome the closing force of the main valve spring.  The main piston is threaded onto the stem of the main disc.  As the piston pulls the stem upward in its cylinder, the main disc unseats and pops open, thus relieving main steam pressure through the SRV tailpipe (outlet).  During the Pilgrim events, SRVs were being used at lower plant pressures in pressure control mode.  In this mode, operators manually open the valves from a switch in the control room, as needed, to lower plant pressure.  The switch sends a signal to the solenoid, which moves the remote air actuator to unseat the second stage disc, causing the main piston to reposition and open the main disc, as described above.   

 Root Cause and Method of Damage
In its initial and interim Part 21 reports, Target Rock concluded that valve internal degradation is initiated during limited flow testing at offsite testing facilities.  Limited flow testing of the Model 0867F 3-stage SRV exposes the valve internals to excessive velocities and impact forces.  The dynamic loads during testing can far exceed those which the valves experience during an in-plant actuation.  This is mainly due to the presence of the gagging device, which is a plate with a small orifice inserted just downstream of the main disc to block off most of the steam flow (see Figure 1 of this document).  The gag is necessary to ensure sufficient inlet pressure to fully open the valve in testing.  It also minimizes the amount of potentially radioactive steam exhausted from the valve during testing.  However, by blocking the exhaust path through the valve outlet, the gag causes a reaction force with the underside of the main disc as the valve begins to open.  The added force caused by differential pressure across the main piston creates a higher than normal opening force on the main valve assembly.  This extra opening force causes the main piston to reach a higher velocity upon valve actuation, which results in excessive impact force when the main spring becomes fully compressed and arrests valve motion.  The impact force leads to damage to valve internal components, such as that discovered when valves from Pilgrim, Hatch, and Fitzpatrick were disassembled.  

Degradation to valve internals—such as plastic deformation of valve threads, loss of lock nut torque, and de-shouldering of the stem and main piston—allows the piston to wobble and/or rotate inside its cylinder.  When a valve in this condition is reinstalled in the plant, steam flow-induced vibrations can cause the main piston rings to fret against the cylinder liner and form grooves over time.  If these grooves become deep enough, and develop a steep ramp angle, they can impede valve motion when the damaged valve is actuated (see Figures 2 and 3 of this document).  The likelihood of impeding valve motion is greater at low plant pressures, where the differential pressure across the main piston is less.  Fretting can also cause wear on the piston rings themselves, allowing steam to leak, which further impacts valve actuation.  Finally, a shortened main spring can lead to lack of sufficient driving force to reseat (close) the SRV following actuation.  

IN 2018-02 Page 6 of 8





Description of Valve Redesign

In 2016, Target Rock implemented design changes on its Model 0867F 3-stage SRVs that reduce main piston velocity and impact forces during limited flow testing.  The design changes slow the rate at which steam flows into the underside of the main piston upon valve actuation.  This, in turn, lowers the driving force behind the main piston, which slows its velocity during actuation and subsequently reduces impact forces when valve motion is arrested.  The design changes also include a modification to the primary pilot seat in order to ensure that valve actuation times continue to satisfy American Society of Mechanical Engineers Boiler and Pressure Vessel Code requirements.
 DISCUSSION
 In the design of boiling water reactors, main steam SRVs support safety functions of both the pressure relief system and the emergency core cooling system (ECCS).  In the pressure relief system, SRVs lift at their design setpoints to prevent overpressurization of the nuclear system.  This protects the nuclear system process barrier from failure, which could result in the uncontrolled release of fission products.  In the ECCS, certain SRVs will lift upon failure of the high pressure coolant injection system in order to reduce plant pressure and allow the low pressure ECCS to protect the reactor during a small break loss of coolant event.

Target Rock SRVs have been in use in the nuclear industry in the United States for several decades.  The original SRV was a 3-stage model introduced in the early 1970s.  Reliability issues with this model led to the introduction of a 2-stage model in the mid-1970s.  The 2-stage SRVs were susceptible to setpoint drift caused in part by corrosion bonding of the pilot valve seat and disc.  Target Rock reintroduced the 3-stage SRV in 1998, and modified the design again in 2008 with the expectation that users of the valve would convert back to the 3-stage model based on improved setpoint performance.  

Since 2011, there have been anecdotal instances in which Model 0867F valves were inspected during testing and found to have internal damage, such as grooves worn into their main cylinders.  However, the primary cause of operability issues for Model 0867F valves between 2011 and 2015 was pilot valve leakage, which is a well-known and monitored phenomenon. 
Cylinder Wall Cylinder Wall
Main  Piston
Piston Ring Grooves formed by Piston Rings
Figure 2:  Expanded Diagram of Groove Formed by Piston Ring Fretting
Figure 3:  Photo of Grooves Caused by Fretting of Cylinder Wall
IN 2018-02 Page 7 of 8

Increased scrutiny following inoperability of Pilgrim’s “C” SRV during the plant’s complicated scram in 2015 led to the discovery of more severe internal degradation of valve internals.  

Target Rock took action to notify the industry of the operating experience at Pilgrim using the process defined in 10 CFR Part 21.  As they identified the root cause of valve damage and operational failures, Target Rock updated stakeholders with interim reports which recommended improved limited flow testing techniques, and notified industry of the availability of an improved valve design.  
 CONTACT
 This IN requires no specific action or written response.  Please direct any questions about this matter to the technical contact(s) listed below or the appropriate Office of Nuclear Reactor Regulation or Office of New Reactors project manager.


 /RA/ (Paul G. Krohn for)   /RA/
 Timothy J. McGinty, Director   Christopher G. Miller, Director  Division of Construction Inspection  Division of Inspection and Regional Support   and Operational Programs   Office of Nuclear Reactor Regulation Office of New Reactors


Technical Contacts: Eric Thomas, NRR/DIRS  301-415-6772  E-mail: Eric.Thomas@nrc.gov

 John Billerbeck, NRR/DE  301-415-1179  E-mail: John.Billerbeck@nrc.gov

Note:  NRC generic communications may be found on the NRC public Web site, https://www.nrc.gov, under NRC Library.  
IN 2018-02 Page 8 of 8

NRC INFORMATION NOTICE 2018-02, “TESTING AND OPERATIONS-INDUCED DEGRADATION OF 3-STAGE TARGET ROCK SAFETY RELIEF VALVES,” DATED:  February 26, 2018



ADAMS Accession No.: ML18029A741          *concurred via e-mail             CAC/EPID: A11008/L-2017-CRS-0058 OFFICE Tech Editor  NRR/DIRS/IOEB NRO/DEI/MEB NRR/DE/EMIB/BC NRR/DIRS/IOEB/BC NAME JDoughtery EThomas TScarbrough SBailey RElliott DATE 11/13/2017 11/30/2017 01/16/2018 02/01/2018 02/01/2018 OFFICE NRR/DIRS/IRGB/LA NRR/DIRS/IRGB/PM NRR/DIRS/IRGB/BC NRO/DCIP/D NRR/DIRS/D NAME ELee TGovan HChernoff (w/comment) TMcGinty (PKrohn for) CMiller DATE 02/06/2018 02/06/2018 02/20/2018 02/22/2018 02/26/2018