ML20245L351
| ML20245L351 | |
| Person / Time | |
|---|---|
| Issue date: | 04/26/1989 |
| From: | Beckjord E NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| To: | Murley T Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20245L355 | List: |
| References | |
| NUDOCS 8905080011 | |
| Download: ML20245L351 (14) | |
Text
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UNITED STATES
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NtJCLEAR R'!GULATORY COMMISSION
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WA 4HING704, D. C. 26553 5
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APR 2 6198g MENORANDUM FOR:
Tnomas E. Murley, Director Office of Nuclear Reactor Sgulation FROM:
Eric S. Beckjord, Director Office of Nuclear Regulatory Research
SUBJECT:
TRANSMITTAL OF GENERIC LETTER ON MOTOR-OPERATED VALVE TESTING AND SURVEILLANCE The subject generic letter is forwarded herewith (Enclosure 1) for transmittal to all licensees and applicants. The Office of Nuclear Regulatory Research (RES) recommends that the Office of Nuclear Reactor Regulation (NRR) issue this generic letter as soon as possible because:
a.
This issue has a high safety significance.
The failure rates of safety-related motor operated valves (MOVs) have proved to be much higher than previously estimated.
It is also now known that the currently required testing fer M0Vs does not pmvide adequate assurance of MOV operability under flow and differential pressure conditions that the valve may experience during transients or accidents.
b.
The NRC position, as outlined previously by NRR and explicitly stated in the generic letter, is that it is the responsibility of all licensees to assure the operability of safety-related equipment and to conduct. meaningful tests to demonstrate operability.
Many licensees are taking no action at this time, because they are waiting for NRC to issue the generic letter.
l c.
It will take some time for the industry to resolve this problem, and therefore, it is prudent to start as soon as possible.
This letter was approved in its current fonn (see Enclosure 2) by the Ommit+ee to Review Generic Requirements (CRGR). A previous var-ica a' +Sa 1
letter was concurred with by the Office for Analysis and Evaluation of Operational Data (AE00).
The Office of General Counsel (0GC) has no legal objections to this letter.
Your staff has concurred with the letter as forwarded to CRGR on February 3,1989 and has been informed of all changes made as a result of CRGR comments.
We have tried to accomodate all coranents received from industry, NRR, 0GC, the Advisory Committee on Reactor Safeguards (ACRS) and CRGR and have resolved almost all of the comments.
However, there is one central issue that could not
Contact:
- 0. Rothberg, EIB/DSIR/RES NL/S 302, X23924 f
8905080011 890426 PDR ORG NREA f
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APR 2 61989 2
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be resollved by compromise. Several ACRS members and several industry representatives recommended restricting the scope of the letter to only the
" risk-significant" M0Vs as opposed to all safety-related MOVs, as was recommended by NRR a.nd CRGR. This is a basic conflict that was resolved in favor of including all safety-related MOVs in the program. The decision was based on the clear regulatory mandate contained ir 10CFR to include all safety-related MOVs in the program, specific instructions from CRGR, and the perceived difficulty of deciding on a list of " risk-significant" MOVs at each plant. Regardirg this last point, industry has not proposed a methodology for determining the plant-specific
" risk-significant" M0Vs.
The Mechanical Components Subconnittee of the ACRS was briefed on the generic letter on March 29, 1989, and the Full Committee of ACRS was briefed on April 7, 1989. We have been informed that ACRS will offer no written comments or endorsement on the generic letter at this time but will continue to study the issue. The Mechanical Components Subconnittee plans to consider this matter again in May.
ACRS appears to be concerned that there is a large discrepancy between NRC and industry (NUMARC and NUBARG) cost estimates. We are convinced that the industry cost figures are inflated. We have provided what we believe to be a conservative (high) estimate of industry implementation costs (see Enclosure 3). Our estfmates, based primarily on industry assumptions, indicate that the program will cost much less than industry projects.
The reason is that plant owners have to l
maintain a base M0V maintenance program.
The added cost, in the context of l
this letter, is the increment required to show adequate performance, and not d
the total cost of a whole new M0V maintenance program. Using our conservative estimate of costs with our best estimate of risk reduction to the public, the cost-benefit ratio is less than $600/ person-rem.
The industry and ACRS appear to be concerned about the possibility of variations in interpretation of the letter by NRC during and after implementation. Con-sistent with the philosophy that it is the responsibility of each utility to assure the operability of their safety-related MOVs, the generic letter is broad in scope, performance oriented, and was written so as to allow flexibility in implementatic: by the licensees. We do-not consi<fer the generic letter to-be vague; however, such considerations should be addressed by writing a detailed and complete NRC Temporary Instruction for guidance of NRC inspection personnel.
This action is already planned by NRR.
RES will be available to assist in the task if requested.
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Eric S. Beckjord, irector Office of Nuclear gulatory Research
Enclosure:
As stated.
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8 NUCLEAR REGULATORY COMMISSION o
j WASHINGTON, D. C. 20555 GENERIC LETTER AS APPROVED BY CRGR T0:
All he lders of nuclear power reactor operating licenses (OLs) or construction permits (cps). (To be referred to as licensees)
I
SUBJECT:
SA h rY-RELATED MOTOR-0PERATED VALVE TESTING AND SURVEILLANCE BACKGROUND In Bulletin 85-03, dated November 15, 1985, and Supplement 1 of Bulletin 85-03, dated April 27, 1988, the NRC recomend that licensees develop and implement a program to ensure that valve motor-operator switch settings (torque, torque l
bypass, position limit, overload) for motor-operated valves (M0Vs) in several specified systems, are selgcted, set, and maintained so that the MOVs will operate under design basis conditions for the life of the plant. NRC assessments of the reliability of all safety-related MOVs, based on extrapolations of the currently available results of valve surveillance performed in response to Bulletin 85-03, indicate that the program to verify switch settings should be extended in order to assure operability of all safety-related fluid systems.
Our evaluation of the data indicates that, unless additional measures are taken, failure of safety-related MOVs and position-changeable M0V's (as defined in the recommended actions) to operate under design basis conditions will occur much more often than had previously been estimated.
The ASME Code Section XI stroke-timing test for MOVs is performed to meet the inservice testing requirements of 10 CFR 50.55a(g).
Section XI testing for MOVs consists of stroking Class 1, 2 and 3 valves open and closed, usually without fluid pressure or flow in the lines, and measuring stroke time. The ASME I
Section XI requirement to stroke and stmke-time MOVs is a useful tool to complement other 9sts in order to provide verification of MOV operability.
Variations in measured stroke times can be significant for DC powered MOVs, and can indicate valve degradation. AGitionally, periodic stroking of MOVs provides valve exercise and provides some measure of on demand reliability.
1 The term " safety-related" refers to those syste:
ain components that are I
relied upon to remain functional during and fol h wi y design basis events to I
ensure (1) the integrity of the reactor coolant pressure boundary, (ii) the capability to shut down the reactor and maintain it in a safe shutdown con-dition, and (iii) the capability to prevent or mitigate the consequences of accidents that could result in potential offsite exposures comparable to the 10 CFR Part 100 guidelines.
2Design basis events are defined as conditions of normal operation, including anticipated operational occurrences, design basis accidents, external events, and natural phenomena for which the plant must be designed to ensure functions (i) through (iif) above.
The design bases for eact plant are those documented in pertinent licensee submittals such as tFe FSAR.
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1 Section XI requires corrective action if a MOV does not e.hibit its required change of disk position.
However, it is now recognized that the Section XI testing alone is not sufficient to provide assurance of M0V operability at design basis conditions.
Assurance of design basis operability is necessary in order to meet the requirements outlined in General Design Criteria 1, 4,18, and 21 of Appendix A to 10 CFR 50 and Criterion XI of Appendix 8 to 10 CFR 50.
The design basis for certain nonnally open primary system MOVs (for example, those serving RWCU and steam supply to HPCI and RCIC turbines in BWRs) demands that these M6Vs close to isolate the largest postulated downstream pipe break outside centsinment. These MOVs are currently the subject of a full-scale 1
blowdown flow testing program being performed by Idaho National Engineering Laboratory (INEL) under NRC spon orship rs part of the resolution of Generic Issue 87, "Faipre of HPCI Steam Line Without Isulstion." Preliminary results of those tests indicate that some M0Vs may be subjected to mechanisms and loads that were not previously accounted for.
INEL's preliminary conclusions indicate that industry sizing equations for MOVs that must perform thi, type of safety-related function may not be conservative fer all design basis conditions.
The purpose of these tests is to confirm that these valves will operate under design basis conditions and, if possible, to identify the causes of any failures. The design, testing, and maintenance of all valves, and assurcnce of their operability, is the responsibility of the licensees.
INEL has concluded that diagnostic systems that measure both stem thrust and motor torque are best suited to predict valve motor performance under design basis conditions. However, based on INEL's prelirirary conclusions, it is not clear that tests of an MOV at low or moderate pressure differentials can be directly extrapolated to determine correct switch settings at design basis conditions using any type of diagnostic techniques, even for single-phase liquid
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flow. Currently, the most accurate method of detemining switch settings and overall competence of the MOV is to perfom testing at or near design basis f
conditions, either in situ or on. prototype valves.
However, demonstrating M0V operability in situ at design basis conditions is not practical for some MOVs. Alternative to testing at design basis conditions that industry has used include testing at low di'feren ial pressure and/or low flow, as appropriate, combined with MOV surveillance using suitable signature analysis diagnostic techniques.
Licensees should assure that any tests conducted using diagnostic techniques, along with in situ tests conducted at. conditions less severe than design baris conditions, will be applied conservatively to ensure design basis operability of safety-related MCYs.
Licensees should 3lso be aware that increasing MOV thrust by increasing torque switch settings, in order to satisfy design basis operability considerations.
On February 1,1989, in Rockville, Maryland, results of the INEL tests were i
described in an NRC sponsored public " Meeting to Review Valve Blowdown Tests." A transcript of the meeting is available from Heritage Reporting Corporation, 1220 L Street, N.W., Suite 600, Washington, D.C. 20005.
a 3
may subject the valve components to increased forces when the MOV is operated l
at nc-load or low-load conditions. 3uch conditions should be evaluated by the licensee to assure that M07 operability is not compromised.
The NRC will j
provide additional information on HOV performance under full-scale blowdown
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test conditions as those results become available. Licensees are specifically cautinned, however, that the INEL tests are nnt directed toward determining the capability and limitations of various M0V diagncstic systems.
Therefore, licensees are also encouraaed to consider the need for industry sponsored MOV test programs to ensure that diagnostic techniques can be used to determine the correct adjustments to ensure operability of those safety-related MOVs 'or which it is not practical to test at design basis conditions in situ.
Assurance of M0V operability is a complex task.
It involves many factors such as development of strong testing and maintenance programs, managemant support and coordination of engineering, maintenance and testing.
This effort should be viewed by all concernsd as a lor.g-term ungoing program.
Licensees that have already performed extensive programs on MOVs have found it very beneficial and Lost-effective to require that all maintenance and adjustments on the MOVs be performed by technicians that have received specific training in that regard.
Surveillance, adjustment, maintenance end repair of safety-related MOVs should be performad in accordance witt quality assi:rance program methods that meet the requirements of 10 CFF. 50.
The following recommended actions are intended to be consistent with NRC's mainteneuce policy statement as published in the Federal Register on March 23,1988(53FR9430).
The nuclear power industry has several generic activities in the area of MOV maintenance and testing. For exa@le, EPRI has published a maintenance guide and intends to publish an applications cuide for MOVs, The results of these efforts may be useful to the industry in developing an effective program.
This letter is part of the resolutior, of Generic )ssue II.E.61, "In Sin:
Testing of Valves " that relates to MOV testing.
1 RECOMMENDED ACTIONS By this letter NRC extends the scope of the program outlined in Bulletin 86-03 and Supplement 1 of Bulletin 85-03 to include all safety-related MOVs as well as all position-changeable M0Vs es defined below. The licensee's program should provide.for>MOVs to be tested, inspected, and maintained so as to>provi % the necessary assurance that they will function when subjected to tb design basis conditions that are to be considered during both normal operation and abnormal events within th design basis of the plant. Although this program should
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address safety-related MOVs and position-changeable MOVs as a minimum, NRC envisions that, as part of a gcod maintenance program, other MOVs in the balance-of-plant should be considered for inclusion in the program, commensurate l
with the licensee's assessment of their importance to safety.
Any MOV in a safety-related system that is not blocked from inadvertent operation from either the control rcom, the motor control center, or the valve itself should be considered capable of being mispositioned (referred to as position-changeable MOVs) and should be included in the program. When determining the maximum differential pressure or flow for position-changeable NOVs the fact that the MOV must be able to recover from mispositioning should be considered.
4
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The program to respond to this letter should address items a. through h. Items i
a.,
b., c. and the first paragraph of d., are repeated, with limited changes,
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from Bulletin 85-03 or from Supplement 1 of that bulletin. The second paragraph of item d. and items e.,
f.,
g., and h. provide additional clarification and guidance.
a.
Review and document the design basis for the operation of each M0V. This documentation should include the maximum differential pressure expected during both opening and closing the MOV for both normal operations and abnormal events, to the extent that these M0V operations and events are
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included in the existing approved design basis.
b.
Using the results from item a. establish the correct switch settings.
This should include establishing a program to review and revise, as necessary, the methods for selecting and setting all switches (i.e., torque, torque bypass, position limit, overload) for each valve operation (opening and closing). One purpose of this Mtter is to ensure that a program exists for selecting and setting valve.sperator switches to ensure high reliability of safety-related MOVs.
c.
Individual M0V switch settings should be changed, as appropriate, to those established in item b.
Whether the switch settings are changed or not, the MOV should be demonstrated to be operable by testing the MOV at the design I
basis differential pressure and/or flow determined in item a.
Testing MOVs at design basis conditions is not recommended where such testing is precluded by the existing plant configuration. An explanation should be I
documented for any cases where testing with the design basis differential pressure or flow cannot practicably be perfonned. This explanation should include a description of the alte natives to design basis differential pressure testing or flow testing that will be used to verify the correct settings.
l Note: This letter is not i'itended to establish a recommendation for valve testing for the condition simulating a break in the line.containing the M0V. However, a break in the line should be considered in the analyses described in items a.,
b., and c. if MOV operation is relied on in the design basis.
Each MOV should b ctroke tested, to, verify. that the M0V is 'aperab!? 7t no-pressure or no-flow conditions even if testing with differential pressure or flow cannot be performed.
l d.
Prepare or revise procedures to ensure that correct switch settings are determined and maintained throughout the life of the plant. These procedures should include provisions to monitor M0V performance to ensure the switch settings are correct. This is particularly important if the i
torque or torque bypass switch setting has been significantly raised above that required.
It may become necessary to adjust MOV switch settings because of the effects of wear or aging. Therefore, it is insufficient. to merely verify that the switch settings are unchanged from previously established values.
The switch settings should be verified, in accordance with the program j
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schedule (seeitemj.). The ASME Code Section XI stroke-timing test required by 10 CFR 50 is not oriented toward verification of switch settings. Therefore, additional measures should be taken to adequately verify that the switch settings ensure M0V operability. The switch l
settings need not be verified each time the ASME Code stroke-timing test is performed.
e.
Regarding item a., no change to the existing plant design basis is intended and none should be inferred. The design basis review should not be restricted to a determination of estimated maximun design basis differential pressure. The design basis review should include an examination of the pertinent design and installation criteria that were usca in choosing the particular M0V.
For example, the review should include the effects on MOV performance of design basis degraded voltage, including the capability of the M0V's power supply and cables to provide the high initial current needed by the M0V to operate.
f.
Documentation of explanations and description of actual test methods used for accomplishing item c. should be retainec as part of the required records for the M0V.
It is also recognized that it may be impractical to perform in situ M0V l
testing at design basis degraded voltage conditions. However, the switch settings established in item b. should at least be established to account for the situation where the valves may be called upon to operate at design basis differential pressure, or flow, and under cegraded voltage conditions.
If the licensee failed to consider degraded voltage, or power supply, or cable adequacy for MOVs in systems covered by Sulletin 85-03, the design i
L review and established switch settings for those h0Vs should be reevaluated.
g.
A number of deficiencies, misadjustments and degraded conditions were discovered by licensees, either as a result of their efforts to comply with Bulletin 85-03 or from other experiences. A list of these conditions (including improper switch settings) is included in Attachment A to this letter for licensee review and information.
h.
Each MOV failure and corrective action taken, including repair, alteration, analysis, test, and surveillance, should be analyzed or Justified and documented. The documentation should include results and
)
l history of each as-found deteriorated condition, malfunction, test, inspection, analysis, repair, or alteration. All docume.itation should be retained and reported in accordance with plant requirernents.
It is suggested that this M0V data be periodically examined (at least every 2 years or after each refueling outage after program implementation) as part of a monitoring and feedback effort to establish trends of MOV operability. These trends could provide the basis for a licensee revision to the testing frequency established to periodically verify the adequacy of M0V switch settings (see items d. and j.).
This monitoring and feedback effort needs a well structured and component oriented system (e.g., the Nuclear Plant Reliability Data System (NPRDS)) to capture, track, and share the equipment history data.
The NRC encourages the use
__.m_ _ _ _ _
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of the industry-wide NPFDS, appropriately modified, for this purpose in view of the multiple uses for this data.
l SCHEDULE The program to respond to this letter should be accomplished in accordance with l
the schedule outlined in items 1. through k. The scheduled da;es should provide for accomplishing item c. soonest for those MOVs that the licensee considers to have the greatest impact on plant safety.
l l
1.
Each licensee with an OL should accomplish all design basis reviews, analyses, verifications, tests, and inspections that have been instituted i
in order to comply with action items a. through h. within 5 years or three refueling outages of the date of this letter, whichever is later.
Each licensee with a CP should accomplish these actions within 5 years of the date of this letter or prior to 0L issuance, whichever is later.
For plants with an OL, the documentation described in items 1. and 2.
below should be available within one year or one refueling outage of the date of this letter, whichever is later. For plants with a CP, the documentation outlined in items 1. and 2. should be available within one year of the date of this letter or prior to OL issuance, whichever is later. The documents should include-1.
The description and schedule for the design basis review recoscended in item a. (including guidance from item e.) for all safety-related MOVs, and position-changeable MOVs as described, and 2.
The program description and schedule for items b. through h. for all safety-related MOVs and position-changeable MOVs.
j.
The program for verification of procedures outlined in ites d., as well as other tests or surveillance that the owner may choose to use to identify potential MOV degradations or misadjustments, such as described in item g., should be accomplished after maintenance or adjustment (including packing adjustment) of each MOV, and per:odically thereafter.
The wrveillance interval should be based ori the licenseet evaluation of the safety importance of each M0V as well as its maintenance and perform-
.uce hk. tory. The..u vaillance interval ;hould nct exc >ed five year: or be justified (g outages, whichever is longer, unless a longer interval can three refuelin see item h.) for any particular MOV.
k.
In recognition of the necessity for pre-planning, refueling outages that start within six months of the date of this letter need not be counted in establishing the schedule to meet the time limits recommended in items i.
and j.
REPORTING REQUIREMENTS Pursuant to 10 CFR 50.54(f), licensees are required to provide information to NRC as outlined in items 1. and m.
7 1.
Licensees shall advise NRC in writing, within 6 months of the date of this letter, that the above schedule and recommendations will be met.
For any date that cannot be met, the licensee shall advise the NRC of a revised schedule and provide a technical justification, in writing.
For any recommendation that cannot be met or that the licensee proposes not to meet, the licensee shall inform NRC and provide a technical justification including any proposed alternative action, in writing.
Licensees shall also submit, in writing, any future changes to scheduled commitments made on the basis of trending results (see items h. and j.).
These revised schedules or alternative actions may be implemented without NRC approval. Justification for the revised schedules and alternative actions should be retained on site.
m.
Licensees shall notify the NRC in writing within 30 days after the actions described in the first paragraph of oction item 1. have been accomplished, This generic letter supersedes the recommendations contained in Bulletin 85-03 l
and its supplement.
Bulletin 85-03 addressees need not make any further I
responses regarding that bulletin or its supplement. The information that was or would have been submitted to NRC in response to Bulletin 85-03 or its suppler 6ent should be retained in accordance with the recommendations of this c,eneric letter.
Documented results or tests or other surveillance that were used to satisfy the ecommended actions of Bulletin 85-03, the supplement to that bulletin, or a voluntary extension of the recommendations in those documents to other H0Vs may be used, to the extent applicable, to satisfy the reconracn@.tions stated herein.
This request is covered by Office of Management ano Budget Clearance Number 1
3150-001 which expires December 31, 1989. The estimated average burden hours is 2000 man-hours per licenseo response, including assessment of the new recocrnendations, searching data sources, gathering end analp.ing the data, and preparing the required letters. These estimated average buroen hours pertain only to the identified response-related matters and do not include the time fc-i the' actual implementation of the requested actions. Comments on the accuracy of this estimate and suggestions to reduce the burden may be directed to the Office of Management and Budget, Room 3208, New Executive Office. Building, Washington D.C.
'20503, and the U.S. Nuclear Regulatory Commission, Records and Reports Management Branch, Office of Information Resources Mar.agement, Washincjton, D.C.
20555.
i If you have any questions regarding this matter, please contact the NRC project l
manager or the technical contact listed below.
James G. Partlow Associate Director for Projects Office of Nuclear Reactor Regulation
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Attachment:
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Contacts: To be determined Dis tributio_n:
RES Chron R. Major RES Circ L. Marsh EIB r/f J. B. Nartin - RV EIB subj.
R. D. Martin - RIV PDR E. McKenna S. Aggarwal C. Michaelson - ACRS G. Arlotto W. Minners R. Baer F. Miraglia i
G. Barber T. Murley i
R. Barrett J. Murphy l
L C. Bartlett K. Murphy - RI l
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j C. Berlinge-J. Page R. Bernero W. Parler J. Boardman - RIV J. Partlow-E.' Brown J. Richardson
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Bosr.ek J. Roe A. Busiik F. Rosa F. Cherr.y D. Ross j
C. Clark -' RV E. Rossi P. Cota-Z. Rosztoczy D. Crutchfield
- 0. Rothberg G. Cwalina Z. kosztoczy L
D. Osnielson - RIII W. Russell - RI L
A. B. Davis - RIII C. Sakenas M. Ernst - RII W. Schwink W. Fanner J. Scinto T. Gillespie L. Shao E. Girard - RII B. Sheron J. Goldberg J. Soiezek B. Grimes E. Sullivan G.. ' Hammer M. Vagins F. Hebdon-H. Va.1dermolen Wm M Hodges S. Varga L
R. W. Houston J. Vora l'
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Huang G. Weidenhamer-H. Woods A. Igne _
S. Israel J. Conran J. Jacobson E. Jorden R. Kiessel l
R. Kirkwcod N. Le
[GENERICLETTERMOV]
- SEE PREVIOUS CONCURRENCE EIB:DSTR*
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l Attachment A of Generic letter Summary of Common Motor-0perated Valve Deficiencies, Misadjustments, and Degraded Conditions 1.
Incorrect torque switch bypass settings 2.
Incorrect torque switch settings 3.
Unbalanced torque switch 4.
Spring pack gap or incorrect spring pack prelead 5.
Incorrect stem packing tightness 6.
Excessive inertia 7.
Loose or tight stem-nut locknut 8.
Incorrect limit switch settings 9.
Stem wear
- 10. Bent or broken stem
- 11. Worn or broken gears l
12.
Grease problems (hardening, migration into spring pack, lack of grease, i
excessive grease, contamination, non-specified grease) l
- 13. Motor insulation or rotor degradation 14.
Iucorrect wire size or degraded wiring 15.
Disk / seat binding (includes thertnal binding) 16.
Water in internal parts or deterioration therefrom
- 17. Motor undersized (for degraded voltage conditions or other conditions) 18.
Incorrect valve position indication
- 19. Misadjustment or failure of handwheel declutch mechanism 20.
Relay problems (incorrect relays, dirt in relays, deteriorated relays, miswired relays) 21.
Incorrect thermal overload switch settings 22<
Worn or broken bearings.
23 Broken or cracked limit switch and torque switch components p
- 24. Missing or modified torque switch limiter plate l
25.
Improperly sized actuators 26.
Hydraulic (ockup 27.
Incorrect metallic materials for gears, keys, bolts, shafts, etc.
28.
De;raded voltas (within design basis) l 29.
Deft.ctive motor control logic 30.
Jxcessive seating or backseating i. rce application 31.
Incorrect reassembly or adjustment after maintenance ard/or testing l
32.
Unauthorized modifications or adjustments 33.
Torqua switch or limit switch binding.
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'F. Miraglia G. Barber T. Murley R. Barrett J. Murphy C. Bartlett K. Murphy - RI
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E. Beckjord T. Novak C. Berlinger J. Page R. Bernero W. Parler J. Boardman - RIV J. Partlow E. Brown J.' Richardson R. Bosnak J. Roe A. Busiik F. Rosa-F. Cherny D. Ross C. Clark - RV E. Rossi P.-Cota Z. Rosztoczy D. Crutchfield O. Rothberg G. Cwalina Z. Rosztoczy L
Di Danielson - RIII W. Russell - RI A..B. Davis - RIII C. Sakenas M. Ernst - RII W. Schwink W. Farmer J. Scinto F. Gillespie L. Shao E. Girard - RII B. Sheron J. Goldberg J. Sniezek B. Grimes E. Sullivan G. Hammer M. Vagins F. Hebdon H. Vandermolen W..K. Hodges S. Varga l
R. W. Houston J. Vora J. Huang G. Weidenhamer A. Igne H. Woods S. Israel J. Conran J. Jacobson E.-Jordan R. Kiessel R..Kirkwood N. Le l.
[ GENERIC LETTER MOV]-
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is EBeckjord INurley 6 /4 /89 3/G /89
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