ML20234D592

Insp Rept 50-285/87-17 on 870608-12.Violation Noted:Measures Not Established to Identify & Control Use of Limitorque Valve Operators Found to Have Thrust Swithes Set So Thrust Limits of Operators Exceeded

ML20234D592
Person / Time
Site:	Fort Calhoun
Issue date:	06/30/1987
From:	Ireland R, Norman D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
To:
Shared Package
ML20234D544	List: ML20234D542 ML20234D576 ML20234D592
References
50-285-87-17, IEB-85-003, IEB-85-3, IEIN-86-029, IEIN-86-29, NUDOCS 8707070269
Download: ML20234D592 (6)

See also: IR 05000285/1987017

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i APPENDIX B i

I U.S. NUCLEAR REGULATORY COMMISSION

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REGION IV

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NRC Inspection Report: 50-285/87-17 License: DPR-40

Docket: 50-285

Licensee: Omaha Public Power District (0 PPD)

1623 Harney Street

Omaha, Nebraska 68102

Facility Name: Fort Calhoun Station, Unit 1 (FCS)

Inspection At: Fort Calhoun, Nebraska

Inspection Conducted: June 8-12, 1987

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Inspector: .[ [. 77#pru%

D. E. Norman, Reactor Inspector, Engineering

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Date

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Section, Reactor Safety Branch

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Approved: 7- m M 6/D/E7

R. E. Ireland, Chief Engineering Section Date~

Reactor Safety Branch

Inspection Summary

Inspection Conducted June 8-12, 1987 (Report 50-285/87-17)

Areas Inspected: Routine, unannounced inspection of actions relative to

IEB 85-03, IEN 86-29, and previously identified inspection finding 285/8616-01.

Results: Within the areas inspected, one violation was identified.

(285/8717-02, paragraph 2.a.(3).) )

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8707070269 870701  !

PDR ADOCK 05000285

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DETAILS

1. Persons Contacted

Omaha Public Power District (OPPD)

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• D. Munderloh, Senior Engineer, Nuclear Regulatory & Industry Affairs

• K. Morris, Division Manager, QA/RA 1

• G. Gates, Manager, Fort Calhoun Station ]

• A. Richard, Manager, Quality Assurance )

• J. Gasper, Manager, Administrative & Training Services j

• M. Core, Supervisor, Fort Calhoun Station Maintenance 1

• R. Andrews, Division Manager, Nuclear Production

J. Drahota, Senior Engineer, Nuclear Production

D. Hendry, Maintenance Engineer, Fort Calhoun Station

J. Fisicaro, Supervisor, Nuclear Regulatory & Industry Affairs

NRC

• P. Harrell, Senior Resident Inspector, Fort Calhoun Station

• Denotes those present at the exit interview.

2. Inspection Summary

a. IEB 85-03 (Closed)

IEB 85-03, " Motor Operated Valve Common Mode Failure During Plant

Transients Due to Improper Switch Settings," was issued as a result

of several events during which motor operated valves (MOVs) failed on

demand due to improper switch settings. The Bulletin requested that

MOVs in certain systems be tested for operational readiness, and that  ;

licensees develop and implement a program to ensure that valve

operator switches are selected, set, and maintained properly to

accommodate maximum differential pressure expected during both

l opening and closing of the valve for both normal and abnormal events

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within the design basis. The licensee submitted a response to the

Bulletin on May 15, 1986, and submitted additional information

requested by the NRC on September 15, 1986.

The inspection was performed to followup on the licensee's activities

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taken in response to IEB 85-03 and commitments made by the licensee

in submittals regarding the Bulletin. The inspection scope included

the following:

(1) Program Review - The commitments made by the licensee in the

submittals to NRC are implemented by several procedures which

are now in place, and which were used for resetting motor

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operated valve switches during the 1987 refueling outage. The

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switches were originally set, in response to the Bulletin,

during the 1985 outage. The following procedures, which

implemented the program were reviewed by the NRC inspector:

MP-MOV-3A, Revision 0, dated March 31, 1987, " Calibration

and Adjustments of Motor Operated Gate and Globe Valves"

MP-MOV-1, Revision 7, dated April 3,1987, " Motor Operated

"Limitorque" Valves Type SMB/HMB Limit Switch and Torque

Switch Replacement and Adjustment Procedure"

MP-MOV-3C, Revision 0, dated March 31, 1987, " Calibration

of the M0 VATS Motor Load Unit"

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l SP-SI-HPSI, Revision 0, dated March 26, 1987, "HPSI Stop

Valves Special Test" 1

Practices for accurately setting the switches to prevent

occurrences as described in the Bulletin were addressed in the

procedures and included:

Specific procedure for determining switch setting values.

Requirement that torque switch settings consider backlash

by setting bypass margin at the time the valve begins to

lift.

Requirement that torque switches-be set with spring pack in

a relaxed condition. l

Checking for backseating by turning handwheel after limit I

switch trip.

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The licensee's program provides reliable operation of MOVs by i

utilizing the Motor Operated Valve Analysis and Test

System (M0 VATS), a system which permits testing, adjusting, and

setting of limit switches, torque switches, and torque switch

bypass which are part of the controls for a M0V. M0 VATS is a

portable signature analysis system designed for field use and

displays and stores the following data: )

axial motion of the worm

motor current

stem load (thrust)

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actuations of torque and limit switches and the torque

l switch bypass

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The valves within the scope of IEB 85-03, each in the HPSI

system are as follows: HCV-311, HCV-312, HCV-314, HCV-315,

HCV-317, HCV-318, HCV-320, and HCV-321. Each valve was tested

and switches were set in accordance with MP-MOV-3A. During a

subsequent test conducted in accordance with SP-SI-HPSI it was

verified that the valves would cycle at or near the maximum

expected delta pressure across the valves.

In addition to the IEB 85-03 valves, the M0 VATS system was used

to test all safety-related MOVs at FCS. These tests were

performed at static conditions (no delta pressure across valve).

During the review of MP-MOV-3A it was identified that the

! procedure would permit setting of the torque switch at a value

which exceeds the design limits of the operator. For instance,

design limits (torque switch setting) of an.SMB-00 operator is

14,000 lbs. The procedure permits a maximum setting of

14,575 lbs. All of the IEB 85-03 torque switches were set below

the design limits. Pending licensee review of all other

safety-related operators to ensure that design limits have not

been exceeded, and a change to the procedure to prevent torque

switches from being set too high, this is considered an

unresolved item (285/8717-01).  ;

(3) Data Review - IEB 85-03 reported that valves failed to operate

because the torque switch bypass had not been set to remain

closed long enough to provide the necessary bypass function on

valve opening with differential pressure conditions across the

valve. Switches were reportedly set for 5 percent of full

stroke. FCS procedures require,the bypass to be set between 10

and 15 percent of the stroke time after the valve begins to

unseat.

Open limit switches were set to trip at approximately 95 percent

of full stroke. After the limit switch had tripped, the

handwheel was turned to bring the valve against the backseat to

ensure that backseating had not occurred. Data reviewed by the

NRC inspector showed no evidence of iackseating; this indicated

that the 95 percent limit switch setting was adequate to prevent

backseating,

i. Review of as-left data showed that all thrust switch settings

I were within design limits of the operators. As-found data for

the initial M0 VATS tests performed during the 1985 outage showed

that five of the eight HPSI valve operators had been operating

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above the allowable thrust limit established by Limitorque.

l This condition had not been identified by the licensee, and

there was no evaluation showing that the valve operators were

acceptable for continued operation. After this discovery, the

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licensee reviewed as-found data for all remaining safety-related

valve operators and found that two had been operating above the

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maximum allowable thrust. .In order to determine operability of

the over-thrust operators, the licensee contacted an engineering i

firm to perform a preliminary stress analysis, based on fatigue. j

testing, of the worse-case loading conditions. The' analysis I

show the following:

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The valve operators are acceptable from a structural and

continued operability ',tandpoint for a total of 240 cycles.

-(It was estimated that the operator has 200 cycles to

date).

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Additional testing is required to justify continued ,

operation beyond 240 cycles at the as-left thrust switch

settings.

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The failure of the licensee to identify the over thrust  ;

condition and to take corrective action is considered a- l

violation of NRC requirements. (285/8717-02)  !

b. IEN 86-29 (Closed)

IEN 86-29, " Effects of Changing Valve Motor Operator Switch

Settings," was provided as an alert that setting torque bypass

switches to meet requirements of IEB 85-03 could affect valve ,

position indicators and signals such as "permissives" to'other i

equipment. The problem occurs when the torque bypass switch and

valve position indicator share the same limit switch rotor. .

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Therefore, when the position of the-rotor was changed-to extend the

range of the torque bypass switch,!the valve open or close position

indication was also changed and did not reflect.the actual-position

of the valve. The licensee has issuec' a memorandum to operations

personnel. instructing them that it is necessary to hold the control

switch in the open or close position for five additional seconds ,

after the indicator lights indicate the. valve position. The licensee

stated that "permissives" and emergency valve operation would not be

effected by the false indicators. This item is considered closed.

c. Followup on Previous Inspection Items

(Closed) Violation 285/8616-01 - This violation resulted from the

acceptance of safety-related cable by the licensee without adequate

documentation to show that all procurement' specification requirements

had been met. Specifically, the Certificate of Conformance (C0C) did.

not identify that the item being certified was Rockbestos

Firewall III cable; therefore, it was not possible to trace the cable

to a Qualification Test Report. The following actions were taken by

the licensee and verified by the NRC inspector:

(1) Documentation was added to the purchase order file to correct

the omission of Firewall III on the' C00.

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(2) Purchasing specifications were revised to require certification

to a specific qualification test report.

This item is considered closed.

3. Exit Interview

The NRC inspector met with the licensee representatives denoted in

paragraph 1 and with Mr. P. H. Harrell, NRC Resident Inspector, on

Jure 12, 1987, and summarized the scope and findings of the inspection,

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