ML20137F167

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Nusco MOV Program
ML20137F167
Person / Time
Site: Millstone Dominion icon.png
Issue date: 03/31/1997
From:
GILBERT/COMMONWEALTH, INC. (FORMERLY GILBERT ASSOCIAT
To:
Shared Package
ML20137F155 List:
References
PROC-970331, NUDOCS 9704010004
Download: ML20137F167 (9)
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Gilbert / Commonwealth (G/C) has completed an assessment of the Northeast Utilities' Motor f Operated Valve related programs and processes. %e efforts conducted bfG/C were aided by the l

use of a highly structured Process Analysis Methodology. This analysis technology provides bpth , ,

i O/C and its clients in-depth, focused, and strategic results in a very short time frame. G/C l gathered data for this prcject from all involved panies within NUSCO, including groups at each

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nuclear unit.

i Although NUSCO is respected throughout the nuclear industry as a leader in many areas, the l NUSCO MOV program assessment has revealed several areas where improvement is both needed j

and possible. The G/C project has developed graphicalprocess models of the MOV processes and i -

has built a substantial repository of knowledge about the processes for use by NUSCO in 4

i addressing areas for improvement. While developing the knowledge base for future process f improvement, G/C also identified a variety of issues and problems which are connected to the j current NUSCO MOV program. 'Ihe issues and problems with the existing program and process generally :re clustered into four main groupings as follows:

\O I. NE&O Level MOV Program

! II. Engineering Level MOV Program j III. MOV Program Schedule j IV. MOV Technical and Data Management i

j A review of the process model shows that the MOV Program is highly Engineering focused and l controlled. The controls for Engineering are with respect to the other organizations providing

}- program functions. The conclusion of that analysis is that engineering is over controlling other j departments tasks through the controls that they are establishing within the program document.

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The MOV Program should be reorganized to better involve all of the appropriate departments. It should incorporate applicable criteria that will be used to evaluate its effectiveness, namely the

NRC Inspection plan. The focus of the program should be the site implementation of the testing j requirements, including configuration control, and maintenance of the valve settings through the j Maintenance Program.

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An overall assessment of the NU MOV Program concludes that the MOV Program is not fully developed, does not fully integrate existing NUSCO programs and does not fully align with the  !

NRC Tapion Plan. These weaknesses are attributed to a lack of management attention to the r
program during its initial development stages. The solution to this problem is to elevate the  ;

process ownership, continue to develop and improve the program by defining the ideal process and  !

developing an action plan to move the process from the as-is to the ideal Specific

recommendations are provided in the program issues. #

1 i G/C believes that the comprehensive validated knowledge base of MOV program insight, which 4

has resulted from this project, gives NUSCO an excellent opportunity to move forward to l implement a first class MOV program.

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l i i l Issues / Recommendations t i

{' 1. The NRC Inspection Plan details specific requirements for j 4 the review of stations MOV Programs. Since these are the  ;

criteria that a station is being evaluated against, efforts  ;

i should be made to include aspects of these inspection I i criteria into the MOV Program. l

} The intent of the generic letter (as stated in the i

! inspection plan) is to insure; that the scope of the program i

! includes all safety related systems and therefore all MOVs  !

! within those systems, that adequate switch settings are i maintained, and that MOV problems are trended. The focus of this intent is with Maintenance. Interviews with site- l t

personnel did not reveal a strong (or even substantial) l j interface with the Maintenance Program. In addition, it was  !

j found that each of the units have a different approach to  ;

preventive maintenance for the MOVs and are following i different guidelines with respect to lubrication. These I conflicts should be resolved and a generic approach i developed by the station Maintenance Departments with assistance from the MOV Team as appropriate.

I As a part of the design basis review, the NRC is required to evaluate the scope to determine' if all appropriate valves

'O r i=o1=a a i= ta Proer a ror r ov ==* i=o1=a a to determine if the- exclusion' is justified. A detailed evaluation of the MOV Program scope should be filed for each station and a description of that evaluation process should be provided in the MOV Program Manual.

The NRC also describes inspection criteria for the review of plans and procedures for; design basis review, verification of actuator capacity, switch setting methodology, capability demonstration (baseline testing, dynamic testing and alternative techniques, . periodic verification. (surveillance testing), MO failure root cause analysis, justification *for corrective actions and trending of MOV failures .and correctib actions. The inspectors are required to determine if the completion of individual recommende actions of the generic letter are scheduled and that they support the completion of- the demonstration of valve capability schedule. In addition the inspectors ara i required to verify that all aspects of the MOV Program are {

, encompassed by the quality assurance criteria of Appendix B  !

to 10CFR Part 50.

The NRC inspection plan integrates the MOV Program inspection with other site, engineering and corporate programs. Specifically, the plan requires a review of the ,

C- management processes governing the program, as well as '

design control for sizing, setting and limitor plates, l

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The MOV Program methodology and personnel should be stabilized to the extent possible to eliminate the

! perception of constant change by the customers. It is  ;

i recognized that the program must to some extent be a living , i i program in that criteria and methodology.will change as the l

{ industry becomes more familiar with techniques to evaluate l MOVs and the causes and resolutions for MOV problems are l better understood.

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i' 4. The MOV Program should be focused on the implementation end I i

at the sites and the interface with maintenance should be I i greatly strengthened. This can be accomplished by I

incorporating the site implementation of the MOV Program  !

4 into the Maintenance Program and establishing the trending i f and surveillance aspects of the implementation program under the purview of the Maintenance Department. This would bring l the MO Program in-line with much of the content of the j discussion in item 1 above.

l 5. Guidance provided to NRC inspectors reviewing design basis i reviews states that " ...the results from such reviews will i be used in the calculations to verify the adequacy of MOV i sizing and switch settings and in establishing conditions i for design basis testing. ...Therefore, the design basis l reviews should not yield overly conservative bounding i values, but should provide meaningful input for other porticns of the generic letter program." It has been determined through interviews that some of the differential pressure data provided for specific valves is overly conservative and therefore the methodology for performing those design basis reviews should be examined.

The inspectors are also required to back out of the data certain of the assumed values (packing load, valve factor, and stem coefficient) as well as rate of loading ef fects.

They will apply margins for degradation at the end of the surveillance interval. It is therefore appropriate that the capability to determine these factors be provided to the plants so that overly conservative methods are not employed.

Currently, the best method for doing this is through torque measuring devices.

During interviews, it was determined that the different units have different approaches to preventive main?.enance.

It was ~ determined that stem. lubrication frequency varies from every refueling outage to not at all. Many of the utilities audited by the NRC in the past year were required to justify lubrication frequencies that were greater than one year. The NRC inspectors have tied lubrication to the choice of stem coefficient of friction. The approach is to verify a generic beginning of PM cycle stem coefficient of

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I friction, allow a degradation factor and then verify that the condition is bounded over the lube cycle by as-found l- -

testing. That is, assume a au of .125 at start of PM cycle j

and through the PM Program implementation maintain the au at (

I no worse than'.15. The design,ers are now free to use au = '

.15 in the sizing equation.  ;

l Additionally, each station was asked on what basis are the 4

MOV actuators overhauled? The answer for three stations was  !

! that overhauls would only be performed on the results of PMs j

! indicating the need. The other station reviewed maintenance

! history and PIRs and determined that all MOVs should be '

overhauled.

Because of the consequences (due to the normal i timing of the testing) of bad test results during l l differential pressure tests, many plants due overhauls just '

{ before the initial base line test. This is in order to put j the valve in the best possible condition prior to.its most

severe test. Additionally, they generally put the ve'ves on )

! a periodic overhaul schedule.  !

1 The application of PM criteria to MOV Maintenance should be  !

l standardized for each of the units. The philosophy should be to enhance the success of the testing program and to l

maintain the valves in a high state of reliability. ,

6.- It- is recommended that the Corporate MOV Program be  :

developed as the driver for all MOV related activities with  !

i uniform site implementation programs. The MOV program

!- should identify all existing and needed interfaces to

! accomplish each aspect of the generic letter requirements.

l Efforts should not be duplicated between organizations,

i.e., if a PI~ is needed to define testing equipment j requirements that document should be prepared by the testing j organization and reviewed by the MOV Team.

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! A training matrix for all positions defined as part of the.

I MOV Team should be developed. The current training, in i accordance with NE&O 2.26 leaves the matter of training up to the individuals supervisor. With different supervisors at each plant for the same positions, different i qualific'.tions a can result for the same job. This is a-case 4

where specific implementing requirements is appropriate.

specific requirements should be identified for the implementing organization. The methodology for the implementation should be left to the appropriate organization. The necessary details to complete an activity should be specified, if that knowledge is only contained within the MOV Team. To the extent possible, the interfacing organization should dhoulder the major responsibility for determining implementing criteria for specific recommendations.

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7. With regard to prioritization of MOVs within the scope of '

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the MOV Program the guidance in Supplement 1 to the generic i i letter states that " ...If a safety problem is identified, '

!' the five year s'chedule of the generic letter is not j

applicable and the licensee must act immediately to correct the problem. In this regard, licensees must meet the '

l reporting requirements of the NRC regulations..." " ...If a j licensee finds that an MOV within the generic letter 89-10 2

program will not operate under design basis conditions, the

, licensee must declare that MOV inoperable. ...

" In l Supplement 3 of the generic letter the NRC states that for j BWRs any deficiencies in the HPCI, RCIC, and RWCU MOVs need

to be given a high priority. " ...all licensees and 1 .

construction permit holders should consider the l applicability of the information obtained from the MOV tests i

and the staff evaluation of the te'st results to other MOVs

} within the scope of Generic Letter 89-10. In addition, all

licensees and permit holders should consider this

! information in the development of priorities for l implementing the generic letter program. ...

I Whil'a there is no specific requirement ~ to establish j priorities for MOVs, other than those stat'ed previously, it .

i only makes good business sense

  • to ' minimize the ste.tions i exposure by prioritizing troublesome valves such as those i with operating history or valves whose design margins are p very -limited. These valves could come up in the testing lQ l

sequence at a point where the available response time to implement a corrective action is not adequate to meet the

! overall commitment.

j j 8. Currently, calculation methodologies are still being defined i and new calculations are being performed to revise previous l . calculations. Interviews with personnel performing the

calculations show that different-assumptions are being used

! for different units (mu '= .15 for MSP-2 and au = .20 for 1

! MSP-1). The use of mu = .15 should be justified and if so l should be.used across.the board as this value will provide j more testing margin (less conservatism). The calculation i generati.on process should be improved to the extent that

calculati.ons are developed as needed by the plant people for i testing purposes.

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  • All calculation generation should be driven by the testing schedule. If calculations can not be completed to support i the test schedule revise the schedule. Different l calculations are needed by the plants at - different times.

j For instance, the people developing special test procedures for differential pressure testing need the differential

,i pressures, flow rates, and system configuration as early as j they can get them in order to get through the procedure j generation process. The people putting the acceptance j criteria into the configuration control process need enough j lead time for the people preparing the AWos to get them i

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4 issued to support testing. l lb0 The calculations are at risk and therefore the testing that i verifies the switch settings if discrete calcalations are changed. The interviewees have suggested that the degraded i voltage calculations need to be re performed. Those calculations could change the outcome of the thrust torque 1

i calculations which could invalidate previous testing and  !

make some valves that were previously operable, inoperable. l i '

$ 9. Test records need to be retrievable to support problem / root  !

cause investigations, etc. As part of the configuration control improvements, test record storage and retrievability 5 shoQld be emphasized. The floppy disks on which the VOTES j data is recorded is perishable. The data should be ,

transferred to optical disk and software developed to i

assemble several traces for comparative purposes during  :

problem investigations.  ;

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I Docket No. 50-336 B16358 i

l Attachment 1 ,

Enclosure 4

, Millstora Nuclear Power Station, Unit No. 2 Check Valve Reliability Analysis and Design Application Review i

t March 1997

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