ML20155K276

Forwards Response to IE Bulletin 85-003, Motor-Operated Valve Common Mode Failures During Plant Transients Due to Improper Switch Settings. Rept Completes Action Item a & Outlines Program to Address Items b-d & F

ML20155K276
Person / Time
Site:	Rancho Seco
Issue date:	05/16/1986
From:	Julie Ward SACRAMENTO MUNICIPAL UTILITY DISTRICT
To:	Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
References
IEB-85-003, IEB-85-3, JEW-86-023, JEW-86-23, NUDOCS 8605280023
Download: ML20155K276 (13)

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• f SACRAMENTO MUNICIPAL UTILITY DISTRICT Cl 6201 S Street, P.O. Box 15830. SacrernantogA 95813; (916) 452 3211 AN ELECTRIC SYSTEM SERVING E HEARJ Ofl,C$1F NIA

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JEW 86-023 May 16,1986 J B MARTIN ADMINISTRATOR U S NUCLEAR REGULATORY COMMISSION REGION V 0FFICE OF-INSPECTION AND ENFORCEMENT 1450 MARIA LANE SUITE 210 WALNUT CREEK CA 94596 DOCKET 50-312 RANCHO SECO NUCLEAR GENERATING STATION UNIT NO 1 RESPONSE TO IE BULLETIN NO. 85-03; MOTOR OPERATED VALVE COMMON MODE FAILURES DURING PLANT TRANSIENTS DUE TO IMPROPER SWITCH SETTINGS IE Bulletin 85-03 requires nuclear power plants with operating licenses to develop and implement a program to ensure that valve operator switches of motor operated valves (MOV's) in the'high pressure coolant injection / core spray and 9mergency feedwater systems are selected, set, and maintained.

properly. The-attached reprt details the District's program to address IE Bulletin 85-03 action items. Also, the District is expanding certain elements of this program to cover other -important plant MOV's.

The District has completed Action Item a of IE Bulletin 85-03 (review and documentation of the design basis for the operation of each identified

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valve) and presents this information in'the attached report. The report

also outlines the program to address IE Bulletin 85-03 Action Items b

- through d and completion of~the written report as required by Action Item f. The schedule for completing these items is also included in the attached report. In addition, the District will incorporate the items of IE Notice 86-29, " Effects of Changing Valve Motor-0perator Switch Settings."

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PDR ADOCK 05000312 G PDR- L.

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I J. B. Martin May 16,1986 If you have any questions, pleite call Jerry Delezenski of my staff at (209) 333-2935, extension 4909.

_J ~Ef WARD Y/

ASSISTANT GENERAL MANAGER, NUCLEAR Sworn to and subscribed before me this day of May, 1986 g2'd

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'?s PATRICIA K. GEISLER

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kg< ratscir.u. orrece is SAChA51 ENTO COUNTY -

l My convnission bpires February 16,1984

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Attachment

ATTACHMENT T0 JEW LETTER 86-023 Dated May'16, 1986 I. E. BULLETIN NO. 85-03 MOTOR OPERATED VALVE COMMON MODE FAILURES DURING PLANT TRANSIENTS DUE TO IMPROPER SWITCH SETTINGS Program for Compliance to IEB 85-03 i

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TABLE OF CONTENTS

1. INTRODUCTION 1 II. DISCUSSION 1 III. PROGRAN DESCRIPTION 2

1. Valve data collection and establishing current conditions 4

2. Operator refurbishment 5

3. Analytical determination of torque and thrust 5

4. Setting of switches using the analytical values 6

5. Testing to confirm the valve will perform when required to mitigate an accident 6

6. Revision of procedures to ensure the switches are correctly set, maintained and altered as required in a controlled manner 7 IV. SCHEDULE 8 TABLE 1 9 e

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1. INTRODUCTION IE Bulletin 85-03 requires that a written report be submitted to the NRC within 180 days of bulletin issuance. This report documents the design basis operating conditions for motor operated valves in the High Pressure Injection (HPI) and Auxiliary Feedwater ( AFW) Systems which are required to function in order to mitigate any Design Basis Accident.

This submittal defines a program and schedule for checking, documenting, verifying, and maintaining proper switch settings for the active motor operated valves identified in these two systems.

II. DISCUSSION A study (ERPT-E0181) has been conducted on each of the Rancho Seco Updated Safety Analysis Report (USAR) Chapter 14 accidents to identify the motor operated valves which are required to function in order to mitigate each event. The high pressure injection and auxiliary feedwater valves required for accident mitigation are listed on the attached Table 1. Also, listed on Table 1 is the maximum credible differential pressure imposed upon each valve.

The maximum dif ferential pressure on each valve was determined by evaluating the systems (HPI, AFW) parameters of each valve. In addition to evaluating the Chapter 14 accidents, the Normal and Emergency Operating Procedures were reviewed to ensure the most severe differential pressure conditions were identified.

1 The method af evaluation of each event was to establish the initial conditions of each component prior to the event. The changes to the

, system parameters due to the event were then evaluated for changes (position and parameter) on the valves of interest. Numerous motor operated valves in the high pressure injection and auxiliary feedwater system are commanded to a specific position by automatic protection systems. These automatic position changes plus other manual operator commanded (even spurious) position changes were evaluated to determine which condition produced the maximum differential pressure upon each valve for each valve function (open or closed).

The valves listed in Table 1 are those motor operated valves in the HPI and AFW Systems which are required to be positioned or repositioned to provide the system desiga function (i.e. supply fluid) during each evaluated operating circumstance and each accident of Chapter 14 of the Rancho Seco Unit 1 USAR.

III. PROGRAM DESC.'IPTION IE Bulletin 85-03 describes a phased program. The first phase is to determine the dif ferer tial pressure conditions for each motor operated valve and to establish a second phase program. The phase 2 portion of IE Bulletin 85-03 will involve the following steps:

1) Valve data collection and establishing current conditions.

2) Operator refurbishment.

3) Analytical determination of the operator thrust and torque.

4) Setting of the switches using the analytical values.

5) Testing to confirm the valve will perform when required to mitigate an accident.

6) Revision of procedures to ensure the switches are correctly set, maintained, and altered as required in a controlled manner.

Prior to initiating the above activities, a training program will be conducted for Maintenance (Electrical and Mechnical), Quality, and Engineering and Operations personnel who will be directly involved in the motor operator work. Thii training program will provide a

. familiarization with motor operators in general.

Specific attention will be given to how the torque and limit switches function, the switch setting methodology, and what occurs when a i switch trips. The training program will provide an opportunity for the maintenance personnel to get hands-on experience prior to going into the program. The training program will also cover the use of analysis and test equipment to determine final switch settings and l

l operator thrust.

l The Valve Actuator Training program provides maintenance personnel with the necessary hands-on practice to troubleshoot and repair the problems.

l Hands-on training includes supervised assembly and disassembly of motor operator, practice for diagnosing limit and torque switch settings, trouble shooting, and repairs.

1) Valve Data Collection and Establishina Current Conditions The current switch settings will be obtained by removing the limit switch compartment cover on each motor operator and recording the limit switch positions by manually moving the valve using the handwheel. The torque switch setting and the torque load on the handwheel will be recorded. The Name Plate data, valve stem thread pitch, lif t, operator and valve type and size, and valve pressure rating will be recorded. Using the data obtained and using the analytical method to determine stem load, the hand wheel torque will be converted into a stem load. This will constitute the current condition for the operator. Using the data collected and the operating conditions determined in Phase 1, the analytical load required to be placed on the stem for the most adverse operating condition will be determined and documented. The analytical methodology will be documented in calculations using SMUD Nuclear Engineering procedures and will be used to determine and revise the switch settings. The switch settings will be documented on controlled Engineering drawings and will form part of the configuration control for the Rancho Seco Nuclear Power Plant. The analytical "most adverse" load will be compared to the current condition and compared against the allowable conditions for the valve, against the allowable thrust and torque for the operator, and against the allowable motor usage torque to determine if the operator is properly sized.

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, 2) Operator Refurbishment i

In order to ensure the motor operator is. in proper working condition, i the motor operators'will be refurbished. Each motEr operator will be partially disassembled and inspected to determine the extent of disassembly and repair required. Once the operators have been inspected, each motor operator will be refurbished as identified by the inspection. This will ensure the operator is in an acceptable condition mechanically. This work will be conducted in accordance with the manufacturer's requirements using procedures with appropriate i

quality inspection points.

L l 3) Analytical Determination of Toraue and Thrust i

The maximum allowable load on the valves will be determined by an 4

analytical method using thrust and torque values obtained through the valve vendors. Valve manufacturers and motor operator vendors will be requested to furnish the loads for the listed conditions and the maximum loads for the valves.

The methodology and data base will be obtained through site records, standard operator sizing procedures available from the operator manufacturers, and from direct infonnation received from the valve manufacturers. The use of this analytical methodology will establish a load and a corresponding handwheel torque required to achieve the load. The limit switch settings will be established as a standard j percent open for the open torque switch bypass setting. This position j

will be standardized for all valves to eliminate confusion in setting the switches.

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4) Setting of the Switches Using the Analytical Values f

Following operator refurbishment (2 above), the torque and limit switch settings will be made on the operators. The torque switch settings will be input through the actuator handwheel and set to a-specific value of handwheel torque. The open torque bypass switch setting will be a fixed percentage of disc motion for all motor operated valves. The open limit switch settings will be adjusted to ensure the valves are not back seated. The three-way valves will be set to torque out.in both the open and closed directions. The x handwheel torque values and corresponding torque switch settings will be recorded along with the limit switch positions.

5) Testing to Confirm the Valve Will Perform When Required to Mitiaate an

. A_gcident Once the operators have been refurbished and the new switch settings fixed, the motor operated valves will receive a-flow and delta p test as close to the limiting operating conditions identified as is

, practical. Those' valves that'_do not receive a full: flow and delta p' test will have an analytical justification provided to. compare the

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analytical load versus the test load to . identify the margin available. The test program will record as appropriate, valve stroke time, confirmation of switch operation, inlet and outlet pressures, flow, and system alignment. Adequate system, equipment, and personnel-safety precautions will be maintained during the tests to prevent injury or equipment damage.

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6) Revision of Procedures to Ensure the Switches Are Correctly Set.

Maintained. and Altered as Required in a Controlled Manner The District will prepare / revise Nuclear Engineering Precedures to ensure that correct switch settings are determined and maintained throughout the-life of the plant. The switch settings will be documented on controlled engineering drawings and will form part of' the configuration control for the Rancho Seco Nuclear Power Plant.

Applicable industry standards will be considered in the preparation of these procedures. The valves will be periodically tested to ensure the proper load is being applied by the valve motor operator. The bypass ~ limit switch setting and open limit switch setting will also be verified by test. The torque / load numerical settings will be verified on a schedule consistent with valve usage.

IV. SCHEDULE The following is the schedule for completion of our program for compliance with IE Bulletin 85-03.

Scheduled Comoletion Date

1) Determination of the differential Complete pressures for the MOV'S covered in the IE8 85-03 program

2) Submittal of program and schedulefto Complete the NRC

3) Training of Personnel:

a) Maintenance Complete b) Quality Complete c) Operations 9/5/86

4) Preparation / Revision of Procedures 8/29/86

5) Valve data collection 8/4/86

6) Analytical determination of torque 8/18/86 and thrust

7) Setting of switches 8/29/86

8) Operator refurbishment (All of 11/2/87 these MOV'S except SFV-30801 and

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HV-23004 are included in the upgraded maintenance program required for EQ)-

9) Testing 11/13/87 10)-Submittal of Final Report to the..NRC 1/15/88 or within 60 ,'

days of-program . . -

completion ,

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.. ' TABLE 1, LIST OF MOV'S AND THEIR DIFFERENTIAL PRESSURES INCLUDED IN IEB 85-03 System Valve Number Function P P Opening Closine AFW SFV -'20577 AFW Bypass 1340 1340 20578 HV - 31826 AFW Cross Connect 1340 1340 31827 SFV - 30801 AFW Pump Turbine 1100 Isolation HV - 20569 Main Steam to AFW 1100 1100 20596 Turbine HPI SFV - 23809, 10, HPI Isolation Valves 2960 2765 i 11, 12 SFV - 22005, 06, Letdown Isol. Valves 2150 2105 23, 25 HV - 22007, 22008 SFV - 24004 RCP Seal Return 2150 2150 SFV - 23645, 23646 MU Pump Recirc. 2400 2960 SFV - 23604 Makeup Isolation 2960 2960 SFV - 23508 MU Tank Isolation 20 20 SFV - 25003, 25004 BWST Isolation 20 20 SFV - 23616- RCP Seal Injection 2960 HV - 26105, 26106 R.B. Sump Isolation 20 HV - 26007, 26008 LPI - HPI X-Connect 190 HV - 23004 'Three-way Valve 143 1001E