ML14275A162
| ML14275A162 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Nine Mile Point, Oyster Creek, Quad Cities |
| Issue date: | 09/25/2014 |
| From: | Sharkey J Exelon Generation Co |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| 50495 | |
| Download: ML14275A162 (4) | |
Text
0912512014 U.S. Nuclear Reeulatorv Commission Operations Center Event ReDort Pavo I Power Reactor Event #
50495 Site: OYSTER CREEK Notification Date/ Time: 09/25/2014 16:35 (EDT)
Unit: 1 Region: 1 State: NJ Event Date/ Time: 09/23/2014 15:55 (EDT)
Reactor Type: [1] GE-2 Last Modification: 09/25/2014 Containment Type: MARK I NRC Notified by: JEREMY SHARKEY Notifications: MEL GRAY R1DO HQ Ops Officer: MARK ABRAMOVITZ NICK VALOS R3DO Emergency Class: NON EMERGENCY PART-21 GROUP E-MAIL 10 CFR Section:
21.21(d)(3)(i)
DEFECTS AND NONCOMPLIANCE Unit Scram Code RX Crit Init Power Initial RX Mode Curr Power Current RX Mode 1
N No 0
Refueling 0
Refueling 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.
"Identification of Facility and Component: Oyster Creek Nuclear Generating Station / Electromatic Relief Valve Actuator, Dresser Valve Type 6" Model 1525-VX "Identification of Component Manufacturer and I or Supplier: Dresser Industries.
"Nature of Defect: 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.
"Safety Significance (e.g., substantial hazard that is or could be created): Identified condition is a Substantial Safety Hazard since it could cause EMRV to be inoperable, which could result in a loss of safety function.
"Date of Discovery of Initial Condition (taken from the IR): 06120114 "Date of Discovery of the Substantial Safety Hazard (date of approval of the technical evaluation): 09122114 "Recommended Actions: Change the design to mitigate the cause of the actuator parts (i.e., springs, guides and posts) interacting which results in unexpected wear due to vibration induced fretting.
"Number and Locations of All Defective Components: Two EMRVs located in the Drywell on the Main Steam piping.
"Any Advice Related to the Defect: Consider actuator design change if vibration conditions at the valve location results in unexpected wear of the EMRV actuators. Perform actuator as-found stroke testing before removal for refurbishment to determine in situ operability of the component. With current design, ensure posts are aligned such that preferential wear does not occur. Spring should be optimally centered on the guide and the post and guide should be equidistant around the full circumference of the bushing.
"Contacts (name, Title, Location, Phone Number, etc.): Sylvain L. Schwartz, Senior Staff Engineer, Oyster Creek Nuclear Generating Station, Phone: (609)-971 4558, Email: sylvain.schwartz@exeloncorp.com" The licensee notified the NRC Resident Inspector.
Plants with similar Dresser EMRVs: Nine Mile Point, Quad Cities, and Dresden.
NRC FORM 361 U.S. NUCLEAR REGULATORY COMMISSION (12-200M)
OPERATIONS CENTER REACTOR PLANT EVENT NOTIFICATION WORKSHEET EN #
NRC OPERATION TELEPHONE NUMBER: PRIMARY - 301-816-5100 or 800-532-3469*, BACKUPS -- [1st] 301-951-0550 or 800-449-3694*.
1"2ndl 301-415-0550 and I:3rdl 301-415-0553
- 1 i,-pn*=o=
- ,hn mnintnin thoir nwn *T'R nr nrnvirtud th*,* t~l~nhnni= niln~hl~r NOTIFICATION TIME FACILITY OR ORGANIZATION UNIT NAME OF CALLER CALL BACK #
16:35 EDT Oyster Creek 01 Jeremy Sharkey (609) 971-4667 EVENT TIME & ZONE EVENT DATE POWER/MODE BEFORE POWERIMODE AFTER 15:55 EDT 09/23/2014 0%
0%
EVENT CLASSIFICATIONS 1-Hr. Non-Emergency 10 CFR 50.72(b)(1)
E] (v)(A)
Safe SID Capability AINA E] GENERAL EMERGENCY GEN/AAEC E]I TS Deviation ADEV E] (v)(B)
RHR Capability AINB SITE AREA EMERGENCY SIT/AAEC 4-Hr. Non-Emergency 10 CFR 50.72(b)(2)
C] (v)(C)
Control of Rad Release AINC El ALERT ALE/AAEC [] (i)
TS Required S/D ASHU El (v)(D)
Accident Mitigation AIND El UNUSUAL EVENT UNU/AAEC j]
(iv)(A)
ECCS Discharge to RCS ACCS E] (xii)
Offsite Medical AMED 50.72 NON-EMERGENCY (see next columns) Ej (iv)(8)
RIPS Actuation (scram)
ARPS Ej (xiii)
Loss Comm/Asmt/Resp ACOM El PHYSICAL SECURITY (73.71)
DDDD L] (xi)
Offsite Notification APRE 60-Day Optional 10 CFR 50.73(a)(1)
El MATERIAL/EXPOSURE B???
8-Hr. Non-Emergency 10 CFR 50.72(b)(3)
EIl Invalid Specified System Actuation AINV El FITNESS FOR DUTY HFIT E] (ii)(A)
Degraded Condition ADEG Other Unspecified Requirement (Identify)
]j OTHER UNSPECIFIED REQMT. (see last column) 0 (ii)(B)
Unanalyzed Condition AUNA ![
10 CFR 21.21 (d)(3)(i) Defect NONR E INFORMATION ONLY NINF El (iv)(A)
Specified System Actuation AESFE NON R DESCRIPTION Include: Systems affected, actuations and their initiating signals, causes, effect of event on plant, actions taken or planned, etc. (Continue on back)
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) 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.
NOTIFICATIONS YES NO WILL BE ANYTHING UNUSUAL OR YES (Explain above)
NO NRC RESIDENT 21 El
___E NOT UNDERSTOOD?
STATE(s)
El Z
[_E DID ALL SYSTEMS
[
YES LOCAL
[
El FUNCTION AS REQUIRED?
YSEp a
OTHER GOV AGENCIES E_
[_
El MODE OF OPERATION ESTIMATED ADDITIONAL INFO ON BACK U N T IL.C O R R E C T E D:.._A R E S T A R T D A T E :
N / A E l N O MEDIA/PRESS RELEASE El
[
El UNTIL CORRECTED:
N/A (MM/DDNYYY) 1]
YES NRC FORM 361 (12-2000)
PAGE I OF 2
I NRC FORM 361 U.S. NUCLEAR REGULATORY COMMISSION (12-2000)
OPERATIONS CENTER REACTOR PLANT EVENT NOTIFICATION WORKSHEET EN #
NRC OPERATION TELEPHONE NUMBER: PRIMARY - 301-816-5100 or 800-532-3469*, BACKUPS -- [1stI 301-951-0550 or 800-449-3694*,
r2ndl 301-415-0550 and [3rdl 301-415-0553
- 1 ie.ene=p=r whn ma*intain thair nwrn I=TR arm nrrnwIrl., th,=¢p t*=l~nhnn*, nl Jrh==re NOTIFICATION TIME FACILITY OR ORGANIZATION UNIT NAME OF CALLER CALL BACK #
16:35 EDT Oyster Creek 01 Jeremy Sharkey (609) 971-4667 EVENT TIME & ZONE EVENT DATE POWERIMODE BEFORE POWER/MODE AFTER 15:55 EDT 09/23/2014 0%
0%
EVENT CLASSIFICATIONS 1-Hr. Non-Emergency 10 CFR 50.72(b)(1)
Cl (v)(A)
Safe S/D Capability AINA El GENERAL EMERGENCY GENIAAEC
] EI TS Deviation ADEV E] (v)(B)
RHR Capability AINB SITE AREA EMERGENCY SIT/AAEC 4-Hr. Non-Emergency 10 CFR 50.72(b)(2)
E] (v)(C)
Control of Rad Release AINC l ALERT ALE/AAEC [(i)
TS Required S/D ASHU E (v)(D)
Accident Mitigation AIND El UNUSUAL EVENT UNU/AAEC El(iv)(A)
ECCS Discharge to RCS ACCS El (xii)
Offsite Medical AMED 50.72 NON-EMERGENCY (see next columns) j (iv)(B)
ARPS
[
(xiii)
Loss Comm/Asmt/Resp ACOM El PHYSICAL SECURITY (73.71)
DODD Ej (xi)
Offsite Notification APRE 60-Day Optional 10 CFR 50.73(a)(1)
El MATERIAL/EXPOSURE B???
8-Hr. Non-Emergency 10 CFR 50.72(b)(3)
El Invalid Specified System Actuation AINV El FITNESS FOR DUTY HFIT El (ii)(A)
Degraded Condition ADEG Other Unspecified Requirement (Identify)
M OTHER UNSPECIFIED REQMT. (see last column) El (ii)(B)
Unanalyzed Condition AUNA
[
10 CFR 21.21 (d)(3)(i) Defect NONR El INFORMATION ONLY NINF El[ (iv)(A)
Specified System Actuation AESF---
NONR DESCRIPTION Include: Systems affected, actuations and their initiating signals, causes, effect of event on plant, actions taken or planned, etc. (Continue on back)
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 I 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) 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.
NOTIFICATIONS YES NO WILL BE ANYTHING UNUSUAL OR NRC RESIDENT
[]
[]
NOT UNDERSTOOD?
Li YES (Explain above)
[
NO STATE(s)
El Z]
[E DID ALL SYSTEMS LOCAL E]
FUNCTION AS REQUIRED?
YES NO (Explain above)
OTHER GOV AGENCIES El Z
[_E MODE OF OPERATION ESTIMATED ADDITIONAL INFO ON BACK UNTL CRRETE~
N/A MEDIAIPRESS RELEASE El UNTIL CORRECTED:
N/A (MM/TADAYYY)
[N] YES E] NO NRC FORM 361 (12-2000)
PAGE I OF 2