ML20006A502
| ML20006A502 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 01/19/1990 |
| From: | Cockfield D PORTLAND GENERAL ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-89-10, NUDOCS 9001290039 | |
| Download: ML20006A502 (10) | |
Text
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' amm umum-4 Rxtiand Generai sectriccompaw i
David W. Cockfield Vice President, Nuclear l
January 19,.1990 Trojan Nuclear Plant Docket 50-344 4
License NPF-1 i
U.S. Nuclear Rasulatory Connission Attn: Document Control Desk Washington DC 20555 i
Dear Sirs:
Portland Ceneral Electric Compcny (PCR) Rosponse to i
Generic Letter 89-10. " Safety-Related Motor Operated Valvo Tf_ sting anfl Survelysnce" The Wuclear Regulatory Commission issued Cccaric Lotter 80-10. " Safety-Related, Motor-Orarated Velve Testind and Surveillance" on June 28, 1989.
I The teneric letter specified 13 actior. items, labelcOhrough m.
regarding the development and implementation of a testing program to ensure operability of' safety-related motor-operated valves. This letter is submitted in accordance with Item 1. of the generic letter.
Item 1. of the generic letter requires each licensee to (a) adviso the NRC in writing, within six months of the date of the generic letter that the specified schedule and recommendations will be met, or (b) inform the NRC and provide technical justification for any revised schedule or r
recommendation that will not be met.
This letter provides PGE's position to each of the specific recommended actions.
Sincerely,
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.:r Attachment o$O1 woo i c:
Mr. John B. Martin Regional Administrator, Region V U.S. Nuclear Regulatory Commission sgo ;
$U i Mr. David Stewart-Smith
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State of Oregon g4 j Departnient of Energy s
$M Mr. R. C. Barr
-O Q4 NRC Resident Inspector Trojan Nuclear Plant 121 S W Safrron Street Potaw O'egan 97204 Ill
i Trojan Nuclear Plant Document Control Desk i
Docket 50-344 January 19, 1990 License NPF-1 Attachment Page 1 of 9 PORTLAND GENERAL ELECTRIC COMPANY (PGE) INITIAL RESPONSE TO NUCLEAR REGULATORY COMMISSION (NRC) GENERIC LETTER 89-10
" SAFETY-RELATED MOTOR-OPERATED VALVE TESTING AND SURVEILLANCE" Generic Letter 89-10 dated June 28, 1989, requires, in Item 1., that each r
licensee inform the NRC in writing within six months whether the recommendations and schedule of the generic letter will be met. This letter constitutes PGE's initial response to Generic Letter 89-10.
The intent of the generic letter in to ensure that all safety-related Hotor-operated Valves (MOVs) in piping systems can neet design basis operational requiremento for the life of the plant. The generic Intter states that MOV prograw; established by the licensee should provide for "the testing, inspection, and maintenrnce" of those motorized valves.
Prosently, PGE has a proactiva program in each of these three areas.
PGP.
employs trsined, in-house MOV specialists, has an extensive preventative malrlanante program for MOVs, and is a leader in the industry for the replaceme.it of limit and torque switches with Fiberite materini subcomponents.
Currently, PGE is performing periodic signature analysis testing on 100 percent of all (safety-related and non-safety-related)
MOVs in piping systums. PGE also has played an active role in the development of the Electric Power Research Institute (EPRI) application guide for MOVs, participates in the Thrust Committee of the MOV Users Group, and has maintained an aggressive position in evaluating the capabilities of new technologies in the field of MOV diagnostics.
PGE's position on each of the specific recommendations of the generic letter is provided below.
NRC Recommended Action Item a.
" Review and document the design basis for the operation of each MOV.
This documentation should include the maximum differential pressure expected during both the opening and closing of the MOV for both normal operations and abnormal events, to the extent that these MOV operations and events are included in the existing approved design basis."
PGE Response:
PGE will review and document the design basis for the operation of safety-related MOVs in piping systems as indicated in PGE's response to Item i below. Included in this review will be the determination of maximum differential pressure expected during both opening and closing of the MOV for design basis conditions. These conditions will be based on the existing approved design basin.
w Trojan Nuclear Plant Document Control Desk Docket 50-344 January 19, 1990 License NPF-1 Attachment Page 2 of 9 NRC Recommended Action Item 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 letter is to ensure that a f.
program exists for selecting and setting valve operator switches to ensure high reliability of safety-related MOVa."
PCE Rosponse:
PGE recently complet93 a review and revision of established maintenance proce6dres for the setting of switches on MOVs.
However, PGE will incorporate into those procedurer, when applicable, the additionsi results from Item a. above.
@C Foconnqnded A tiotLItem c._
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" Individual MOV switch settings should be changed, as appropriate, to those established in response to item b.
Whether the switch settings are changed or not, the MOV should be demonstrated to be operable by testing it at the design-basis differential pressure and/or flow determined in response to 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 documented for any cases where testing with the design-basis differential pressure or flow cannot practicably bo performed. This explanation should include a description of the alternatives to design-basis differential pressure testing or flow testing that will be used to verify the correct settings.
" NOTE: This letter is not intended to establish a recommendation for valve testing for the condition simulating a break in the line containing the MOV. 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 be stroke tested to verify that the MOV is operable at no-pressure or no-flow conditions even if testing with differential pressure or flow cannot be performed."
PGE Response:
PGE will conduct selective in-plant differential pressure valve testing to validate diagnostic testing methodologies and vendor equations. The secpe and schedule of additional testing and alternatives to testing at
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Trojan Nuclear Plant Document Control Desk i
Docket 50-344 January 19, 1990 License NpF-1 Attachment I
Page 3 of 9 design-basis differential pressure is dependent on the outcome of this 1
selective testing.
The selective testing will be conducted during the 1991 Refueling Outage.
NRC Recommended Action Item d.
" Prepare or revise procedures to ensure that correct switch settings are determined and maintained throughout the life of the plant. There procodures should include provisions to monitor M0V performance to ensure the switch settings are carrect. This is particularly important if the torque or torque bypast switch setting has been significantly raised above that required.
"It. Saay becors necessary to adjurt MOV switch settingr bcrause of the effects of wcar or 053ag.
Thet afore, it is insufficient to merely verify that the switch settings are unchar.ge$ from previously establiched valuec. The switch scttir_gs should to verifled in accordance with the progenm tahadule (see item j.).
The ASME Code Section XI stroke-timing test r9 quired by 10 CFR part 50 is not oriented toward verification of aeitch settings.
Therefore, additional measures should be taken to adequately verify that the switch settings ensure MOV operability.
The switch settings need not be verified each time the ASME Code stroke-timing test is performed."
PGE Response:
Maintenance procedures for determining proper switch settings will be revised as applicable during implementation of the MOV program per Item 1.
pCE has an existing preventative maintenance program in place for all MOVs. Under this program, actuators are rebuilt with inspection of internal components on a six-year basis, preventative maintenance surveys are done on a threo-year basis, and MOVs with reducod operational margins are maintained on an annual basis.
During the maintenance activities, signature analysis is taken on all MOVs to ensure switch settings are correct. This signature analysis is in addition to American Society of Mechnical Engineers (ASME) Code XI stroke-time testing.
NRC Recommended Action Item 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 determination of estimated maximum design-basis differential pressure, but should include an examination of the pertinent design and installation criteria that were used in choosing the
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Trojan Nuclear Plant Document Control Desk Docket 50-344 January 19, 1990 License NPF-1 Attachment page 4 of 9 particular MOV.
For example, the review should include the effects on MOV performance of design-basis degraded voltage, including the~
capability of the MOV's power supply and cables to provide the high initial current needed for the operation of the MOV.
PGE Responso:
PGE agrees with Recommendation e.
t NRC Recommer.ded Action item f.
"gocumentation of explanatiotas and the description of the actual test methods used for accomplisting item c. :noJ2d be retained as part of the required roccrJF I'or th6 MOV.
"It is also recognir.ed that it may be impt actical to yet form in situ MOV testing at design basis degraded voltage evnditions.
Hewever, the switch settings established in response to item b. should at least oo t-P.ab-r 11shed to account for the situation where the varves may be called upon to uporate at design-basis differential pressure or flow and under degraded voltage conditions.
If the licenseo failed to consider degraded voltage, power supply, or cable adequacy for MOVs in systems covered by Bulletin 85-03, the design review and established switch settings for those MOVs should be reevaluated.
"Alternatlwes to testing a particular MOV in situ at design-basis pressure of flow, where such testing cannot practicably be performed, could include a comparison with appropriate design-basis test results on other MOVs cither in situ or prototype.
If such test information is not available, analytical methods and extrapolations to design-basis conditions, based on the best data available, may be used until test data at design-basis conditions becomo available to verify operability of the MOV.
If this two-stage approach is followed, it should be accomplished within the schedule outlined in item 1. and would allow for MOV testing and surveillance to proceed without excessive delay.
" Testing of MOVs at design-basis conditions nood not be repeated unless the MOV is replaced, modified, or overhauled to the extent that the licensee considers that the existing test results are not representativo of the MOV in its modified configuration.
PGE Response:
Documentation of explanations, description of test methods, and testing alternatives will be retained and maintained in the existing PCE document system.
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b Trojan Nuclear plant Document Control Desk I
Docket 50-344 January 19, 1990 License NpF-1 Attachment page 5 of 9 pCE did consider degraded power supply and cable adequacy for MOVs in systems covered by Bulletin 85-03, and will do no in response to this generic letter.
i At the present time, pCE is performing prototype testing on MOVs in the Trojan Training Facility in order to develop a means of verifying alternatives to design basis differential pressure (Dp) testing. As part of pGE's two-stage approach, Trojan intends to apply prototype testing data and experience to in-plant design basis Dp testing. This approach is targeted toward verifying those MOVs with the lomst operating margin.
pGE is sharing the results of these tests with the industry through sponsorship of workshops within the MOV user's group and making all findings available to EpRI and otheft atilj tir,s, It in the Intentir,n of pGE tu demonstrate the acceptance of a statir. test in place of dasign basis.Dp testing in instances where the actuator han been replaced.
modified, or overhauled.
tit 0 Recommended t.ction Item gt "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.
pCE Response:
Based upon our experience, Attachment A of the generic letter is not a complete and comprehensive list of valve deficiencies, misadjustments and degraded conditions.
As an example, presently pCE completes a " zeroing" of the Limitorque torque switch as part of the Quality Assurance acceptance program.
" Zeroing" of a torque switch ensures that a known displacement of the spring pack is equal to the Limitorque design criteria for that switch.
Ensuring the Limitorique design criteria through " zeroing" ensures functionality of the limiter plate.
In some cases, " zeroing" may cause an unbalanced torque switch.
For these cases, identification of an unbalanced torque switch through the measurement of stem thrust would not identify a degraded condition.
pGE's list of deficiencies will be based upon Attachment A except for those items which are not compatible with maintaining the design of the Limitorque actuator.
NRC Recommended Action Item h.
j "Each MOV failure and corrective action taken, including repair, alteration, analysis, test, and surveillance should be analyzed or
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F Trojan Nuclear plant Document Control Desk Docket 50-344 January 19, 1990 License NPF-1 Attachment i
Page 6 of 9 justified and documented.
The documentation should include the results and history of each "as found" deteriorated condition, malfunction, test, inspection, analysis, repair, or alteration. All documentation should be retained and reported in accordance with plant requirements.
"It is suggested that these MOV data be periodically examined (at least every 2 years or after each refueling outage after program implemen-tation) as part of a monitoring and feedback effort to establish trends of MOV operability.
These trends could provide the basis for n licensee revision of the testing frequency catablished to periodically verify the adequacy of MOV switch settings (see iterm d. and j.).
For this monitoring and feedback effort, a well-structured and component-oriented system (i.e., the Nuclear Plant Reliability Data System (NPRDS)) is i
needed to capture, track, and sh&re the equ!.pment history data. The NRC encourages the use of the industry-wide FFRDS, appropriately modified, for this purpose in view of the multiple uses of this data."
PGE Response:
PGE takes exception to the recommended two-year analysis on a generic basis because of the conservatism that exists with some of the MOVs.
PGE will review valves under the existing PGE preventative maintenance program which involves actuator rebuild every six years, surveys every three years, and annual surveys for those valves with a reduced operating margin. Documentation of failures and corrective actions, including malfunctions, alterations, analysis, or repair are presently maintained in the maintenance request historical files.
In 1990 PGE will be implementing the Maintenance Evaluation Trending Systems (METS), a computerized data base containing failure codes and corrective action codes for maintenance requests since 1985. The system is automated to identify componer.ts receiving repetitive or excessive maintenance requests, and will be used to establish trends of MOV
-operability. The present format of the METS will not be compatible with a two-year analysis, but it will continuously identify problem components.
This monitoring and feedback system is a well-established and component-related system like NPRDS; however, it is not compatible with industrywide programs at this time.
In addition, PCE is a part of the NPRDS network.
NRC Recommended Action Item:
Schedule "The program to respond to this letter should be implemented in accordance with the schedule outlined in items 1. through k. below.
The scheduled dates should ensure that item c. is implemented soonest for those MOVs the licensee considers to have the greatest impact on plant safety."
Trojan Nuclear plant Document Control Desk Docket 50-344 January 19, 1990 License NPF-1 Attachment Page 7 of 9 PGE Response:
pCE has made available to vendors the test stand in the Trojan Training Facility for demonstration and verification of their diagnostic systems.
PGE has evaluated four commercially available diagnostic systems to date. Based on these evaluations it has been determined that all commerically available diagnostic systems are not independently verified to measure stem thrust under both static and dynamic conditions.
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Despite the limit atior.s of commercially available 6iagnostic systems, PGE's intentich is to move toward meeting scheduled completion dates.
However, prior to starting in-plant testing, PGE will have to c.or.plete in house verification testing to demonstrate that the chosen diagnostic system can accurately measure stem thrust under both static and dynamic conditions. Other uncertainties such as rate-of-loadind and " similarity" of valves are also concerns to the industry which PGE will be working to resolve.
Each of these three: diagnostic equipment verification testing, the actuator phenomena called rate-of-loading, and defining
" similarity" of valves must be considered in establishing a schedule for completion.
NRC Recommended Action Item i.
l "Each licensee with an operating license (OL) should complete all design-basis reviews, analyses, verifications, tests, and inspections that have been instituted in order to comply with items a. through h.
within 5 years, or three refueling outages, of the date of this letter, whichever is later.
Each licensee with a construction permit (CP) should complete thece actions within five years of the date of this letter or l
before the OL is issued, whichever is later.
l "For plants with an OL, the documentation described in Items 1. and 2.
below should be available within 1 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 j
year of the date of this letter or before the OL is issued, whichever is later.
l "1.
The description and schedule for the design-basis review recommended in item a.
(including guidance from item e.) for all safety-related MOVs and position changeable MOVs as described, and" l
"2.
The program description and schedule for items b. through h. for all safety-related MOVs and position-changeable MOVs."
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Trojan Nuclear Plant Document Control Desk Docket 50-344 January 19, 1990 bicense NPF-1 Attachment Page 8 of 9 i
pCE Response PGE cannot et this time commit to meeting the five year program deadline for reasont >utlined in Schedule above.
Selective testing completed j
during the 1991 Refueling Outage (as described in the response to Item c) will enable PGE to state with confidence Whether the five year schedule will be met.
The full MOV program schedule with commitment of completion dates for all items (a through h) will be provided within sixty (60) days of completion of the selective testing.
NRC Reconnended Action Item _31 "The program for the verification of the procedures outlined in Item d.,
as well as other tests or surveillance that the owner may chooso to use to identify potential h0V destadatious or misadjustments, such as those described in Attachment A, should bo implemented af ter raintonar.co or adjustment (including packing adjustment) of each MJV, anu periodically thereafter.
The surveillance interval should be based on the licensee's evaluation of the safety importance of each MOV, as tell as its maintenance and performance history. The surveillance interval should not exceed 5 years or three refueling outages, Whichever is longer, unless a longer interval can be justified (soo item h.) for any particular MOV."
PCE Response:
Presently PGE completes surveillance intervals on a three-year preventative maintenance cycle. As PGE develops the METS program, the surveillance interval will be based on PGE's evaluation of each valve's operating margin and test history.
Exceptions to the five-year surveillance interval will be based on engineering review of individual valvo-operating criteria, such as operating margin or number of valve strokes per year, environment, actuator size, and usage.
NRC Recommended Action Item k.
"In recognition of the necessity for proplanning, refueling outages that start within 6 months of the date of this letter need not be counted in establishing the schedule to meet the time limits recommended in items 1.
and j."
PGE Response:
PGE plans no refueling outages starting within six months of the date of the generic letter.
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Trojan Nuclear Plant Document Control Desk Docket 50-344 January 19, 1990 License WPF-1 Attachment Page 9 of 9 NRC Recommended A,ction Item 1.
"Each licensee shull advise the 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, including any proposed alternative action, in writing.
For any recommendation that it cannot meet or proposes not to meet, the licensee shall inform the NRC and provide a technical justification, including any prcposed alternative action, in writing.
"Each licensee shall also submit, in writing, any future changes to scheduled contaitments; for extnple, changes made on the basis of trwnding results (see items h. an5 j.).
These revised schedules or alternative actions may be implem7ated without NRC approval.
Justification for the revised schedule and alternative actions should be retained on site."
PGE Response This letter provides PGE's six month response.
PGE will provide the additional responses for Items i. and m.,
but no further written notification of changes. This information will be readily available on site for NRC review.
NRC Recommended Action Item mz "Each licensee shall notify the NRC in writing within 30 days after the actions described in the first paragraph of item 1. have been implemented."
PGE Response:
PCE will respond within 30 days of the completion of the actions described in the first paragraph of Item 1.
In conclusion, PCE will continue its tradition of scheduled MOV maintenance, inspection, and testing, and work to incorporate the various recommendations of the generic letter as clarified above into the established MOV program.
PGE will continue research efforts in the areas of diagnostic system accuracy verification, rate of loading testir.g, and valve " similarity".
JAV/bsh 4058W.190