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Event Notification Report for December 6, 2011

U.S. Nuclear Regulatory Commission
Operations Center

Event Reports For
12/05/2011 - 12/06/2011

** EVENT NUMBERS **


47497 47498

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Power Reactor Event Number: 47497
Facility: NORTH ANNA
Region: 2 State: VA
Unit: [1] [ ] [ ]
RX Type: [1] W-3-LP,[2] W-3-LP
NRC Notified By: DON TAYLOR
HQ OPS Officer: MARK ABRAMOVITZ
Notification Date: 12/05/2011
Notification Time: 09:35 [ET]
Event Date: 12/05/2011
Event Time: 08:47 [EST]
Last Update Date: 12/05/2011
Emergency Class: NON EMERGENCY
10 CFR Section:
OTHER UNSPEC REQMNT
Person (Organization):
BINOY DESAI (R2DO)
JEFFERY GRANT (IRD)
MARK KING (NRR)

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

Event Text

DISCOVERY OF AFTER-THE-FACT EMERGENCY CONDITION - UNUSUAL EVENT

"At approximately 0847 EST, Unit 1 Letdown Pressure Control Valve, 1-CH-PCV-1145, began acting erratically which resulted in the Letdown Relief Valve, 1-CH-RV-1203, lifting and flowing to the Pressurizer Relief Tank.

"At 0848 EST, the relief valve reseated and the leakage stopped. Approximately 42 gpm leakage resulted from the relief valve lifting.

"This identified flow rate exceeded the threshold for entry into a Notice of Unusual Event under EAL tab SU6.1 due to identified leakage greater than 25 gpm."

The licensee is troubleshooting the Letdown Pressure Control Valve. The licensee notified the NRC Resident Inspector and will notify State and local agencies.

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Part 21 Event Number: 47498
Rep Org: CURTISS WRIGHT FLOW CONTROL CO.
Licensee: CURTISS WRIGHT FLOW CONTROL CO.
Region: 1
City: DANBURY State: CT
County:
License #:
Agreement: N
Docket:
NRC Notified By: MICHAEL WEINSTEIN
HQ OPS Officer: STEVE SANDIN
Notification Date: 12/05/2011
Notification Time: 14:55 [ET]
Event Date: 12/05/2011
Event Time: [EST]
Last Update Date: 12/05/2011
Emergency Class: NON EMERGENCY
10 CFR Section:
21.21 - UNSPECIFIED PARAGRAPH
Person (Organization):
CHRISTOPHER CAHILL (R1DO)
RICHARD SKOKOWSKI (R3DO)
NRR PART21 via email ()

Event Text

PART 21 INVOLVING DEFECTIVE SPRING CLIPS USED AS SEISMIC RESTRAINTS ON TWO SCIENTIFIC MODULES

The following information was received via fax:

"The purpose of this letter is to notify you of a defect in spring clips that form part of the seismic restraint for Scientech CON2000-701 and RTD2100-7403 modules. Details of the defect are provided below and in the attached Technical Bulletin Volume 38, CON2000 and RTD2100 Spring Clips, dated December 2011.

"The written report shall include, but need not be limited to, the following information, to the extent known:

(i) Name and address of the individual or individuals informing the Commission.

Michael Weinstein
Director of Quality Operations
Scientech, a business of Curtiss-Wright Flow Control Corporation
44 Shelter Rock Road
Danbury, CT 06810

Scott Robuck
General Manager
Scientech, a business unit of Curtiss-Wright Flow Control Corporation
200 S. Woodruff Avenue
Idaho Falls, ID 83401

(ii) Identification of the basic component supplied for such facility or such activity within the United States which fails to comply or contains a defect.

PID controller, manufactured by Scientech, Model CON2000-701, Part No. NUS-A056PA
RTD converter, manufactured by Scientech, Model RTD2100-7403, Part No. NUS-A121PA

(iii) Identification of the firm supplying the basic component which fails to comply or contains a defect.

Scientech, a business unit of Curtiss-Wright Flow control Corporation
200 S. Woodruff Avenue
Idaho Falls, ID 83401

(iv) Nature of the defect or failure to comply and the safety hazard which is created or could be created by such defect or failure to comply.

The CON2000-701 is replacement for the obsolete Bailey Meter Company 701 PID controller. It is a panel mounted module that is retained in the panel during seismic events by a spring clip on the top of the modules (part number NUS-P089DB-13) that engages a detent in the panel. The module can be pulled out about one inch out of the rack before the spring clip prevents further movement; full removal requires pressure on the spring clip to disengage the detent.

The module was seismically tested as documented in Qualification Report NUS-A056QA Rev 2. During the CON2000 test, a minor anomaly occurred and was accepted by Scientech as not affecting the qualification results. Recently a client questioned Scientech's acceptance of the anomaly and requested a retest. Scientech agreed to retest the module; the RRS used is attached. During the retest, the spring clip failed to adequately restrain the module.

The balance of the replacements for the Bailey 7000 series - the NUSI 2000 series - are cabinet mounted modules. When they are reconfigured for shelf or panel mounting they become part of the NUSI 2100 series, and the seismically qualified units use the same spring clip. The RTD2100-7403 is the only safety related panel mounted module sold as of December 2011 with the deficient spring clip.

Investigation revealed that the original clip was made of 0.025" thick spring steel. After the seismic qualification test was performed, Revision 4 to NUS-F089DB-13 altered the characteristics of the retaining clip, reducing the force required to disengage the detent. The metal was changed to SS301 stainless steel and the thickness reduced to 0.015" thick. Scientech's design change process required an evaluation of the impact of the change; the evaluation was complet4ed, but did not address the impact on seismic qualification adequately.

These controllers could be mounted in the in the main control room control panels. The failure of the seismic clip could result in the controllers coming out of the panels, impacting other safety related equipment or personnel, and failing to properly control their actuated devices during a seismic event.

(v) The date on which the information of such defect or failure to comply was obtained.

Submitted for evaluation 11/30/11; evaluation completed 12/2/11.

(vi) In the case of a basic component which contains a defect or fails to comply, the number and location of these components in use at, supplied for, being supplied for, or may be supplied for, manufactured, or being manufactured for one or more facilities or activities subject to the regulations in this part.

PLANT CON2000-701 RTD2100-7403

Clinton 4 0
Davis Besse 8 0
Monticello 2 0
Perry 4 0
Susquehanna 20 7

TOTALS 38 7

(vii) The corrective action which has been, is being, or will be taken; the name of the individual or organization responsible for the action; and the length of time that has been or will be taken to complete the action.

1. All five plants were notified and provided with a technical bulletin addressing the problem and the proposed solution.
2. Scientech is expedition procurement of the correct spring clips and will supply them to all affected plants. They can be readily changed out on site.
3. Scientech had previously strengthened its design review process to specifically remind reviewers to evaluate the impact on and need for additional qualifications testing.
4. Scientech will review this event with all engineering staff and emphasize the need for correct reviews.

(viii) Any advice related to the defect or failure to comply about the facility, activity, or basic component that has been, is being, or will be given to purchasers or licensees.

See attached Technical Bulletin. (provided separately)

(ix) In the case of an early site permit, the entities to whom an early site permit was transferred.

Not applicable.

"Should you have any questions regarding this matter, please contact Robert Queenan, Operations Manager, Scientech/NUS Instruments, at (208) 524-9311."

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Thursday, March 29, 2012