NRC-90-0112, Responds to NRC Re Violations Noted in Insp Rept 50-341/90-07.Corrective Actions:Review of RF01 Turbine Work Packages to Identify Where Addl Controls Should Be Placed in Similar Future RF02 Packages Conducted

Responds to NRC Re Violations Noted in Insp Rept 50-341/90-07.Corrective Actions:Review of RF01 Turbine Work Packages to Identify Where Addl Controls Should Be Placed in Similar Future RF02 Packages Conducted

ML20056A682
Person / Time
Site:	Fermi
Issue date:	08/03/1990
From:	Orser W DETROIT EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
CON-NRC-90-0112, CON-NRC-90-112 NUDOCS 9008090021
Download: ML20056A682 (7)

Text

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Detroit ,n e-Edison m(A00 North ha*"'d*hmay. w:.u.

August 3, 1990 m NRC-90-0112 i:

h U.'S. Nuclear Regulatory Commission Attention: Document Control Desk V agton, D.C. -20555 m ,

Reference:

1)- Fermi 2 .

.NRC Docket No. 50/311 NRC License No. NPF-4~,

2) NRC Inspection Report No. 50-yt1/90007, dated June 27, 1990 Su'b ject: ' Response to Notices of Violation 90-007-02/03 S Attached is Detroit Edison's response to the Notice of Violation (NOV) in Reference-2 for the improper overhaul and rebuild of the east turbine bypass valve during the first refueling outage -(RF01) that limited the valve stroke to 88% of full open. Several factors "ere specified in the'NOV as contributing to the problem as follows:

inadequate documented instructions, inadequate review of documents, an I- inadequate program for inspection, failure to est ablish post maintenance. testing, and an inadequate determination of the cause of a condition adverse to quality.

t Detroit Edison has conducted an investigation and has initiated corrective actions to resolve these problems. A root cause determination was performed and the results of this evaluation will be >

discussed herein. -Also included in the response is a discussion of:

(1) corrective. actions taken and the results achieved; (2) corrective

' actions.to be taken-to avoid further violations;'and (3) the date when A

full compliance will be achieved.

Our response date was extended to August 3, 1990, due to a mail delay "

in receiving Reference 2. This extension was discussed with and authorized by Mr. R. DeFayette of your staff on July 9, 1990.

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Should you h' ave any questions regarding this response, please contact 6' Barbara.Siemasz, Compliance Engineer, at (313) 586-1683 4- Sincerel'y-it-

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Page 11 Detroit Edison Response to NRC Notices of Violation 90-007-02/03 ,

hsgarding the East Turbine Bypass Valve Overhaul Conducted During RF01 Statement of Violation 90-007-02  ;

. .. . i "10 CFR 50, Appendix B, Criterion V, " Instruction, Procedures, and  ;

Drawings," states in part "Activitiea affecting quality shall be-prescribed by. documented instructions . . . of a type appropriate  :

.to the circumstances . . .. Instructions . . . shall include appropriate quantitative or qualitative acceptance criteria -for determining that important activities have been satisfactorily Taccomplished." l r

'"10 CFR 50, Appendix B, Criterion VI, " Document Control," states [

.in part " Measures shall be established to control the issuance I of : . . - ., instructic7s . , . . which prescribe all activities affecting quality. These measures shall assure that documents. .

. . . are reviewed:for adequacy . . ."

10 CFR 50, Appendix B, Criterion X, " Inspection," states in part "A program for inspection of activities affecting quality shall be  ;

. established and executed . . . Examinations . . . shall be i performed for each work opers' ion where necessary to assure  ;

quality . . ." .

10 CFR 50, Appendix B, Criterion XI, " Test-Control," states in part "A test program shall be established to assure that 011 testing required to demonstrate that structures, systems, and components .will perform satisfactorily:in service is identified  !

.and performed ~1n accordance with written test procedures which.

incorporate the requirements and acceptance limits contained in applicable design documents." ,

Contrary to the above, while rebuilding of the Important-to Safety east mainsteam bypass valve dcring the fall 1989 refueling outage the licensee:

o Failed to prescribe adequate. documented instructions including the -lack of appropriate quantitative or qualitative acceptance criteria for determining that the east mainsteam 1 bypass valve rebuilding effort was satisfactorily accomplished in that the instructions did not provide appropriate-quantitative acceptr.no/ measurements for the length of valve stroke.

1 o Failed . to establish adequ.' tu meas rea for reviewing the documents associated with the recailding of the east mainsteam bypass valve in that toe review process did not

~1dentify that it was impossible tu properly rebuild the valve with~the instructions provided.

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_o. Failed to establish / execute a program of. inspection-of the east mainsteam bypass valve in-that there were no designated  ;

' inspection points or work ~ observations prescribed. 'l o- Fail $d to' establish testing required to demonstrate that the i sast mainsteam bypass valve would perform satisfactorily in service in that no post maintenance testing was prescribed."  ;

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@ j Detroit Edison Response During the first refueling outage, the east turbine bypass valve was.

overhauled. Upon inspection, the valve seat showed cracks. It was decided to replace the valve disc and stem, as well as the seat.

Later during.the outage on' November 23, 1989, Operations performed-surveillance NPP-24.109.002, which requires stroking of the valve. At '

this time, the Control' Room indication showed 12% open in the fully closed position. Maintenance I&C was contacted to troubleshoot the ,

apparent indication problem. At this time, I&C determined that a preventive maintenance (PM) activity was due on the position >

indication for-this valve. ~In performing the PM, the valve again-

! showed a 0-885 stroke on the indication. The. analog position indication was subsequently recalibrated to read 0-1005_ full stroke.

The surveillance was subsequently re-run and passed.

During~startup following the refueling outage in December, Operations personnel' noticed a dual indication problem on the east turbine bypass <

. valve. Work Request 014C891215.was written to~ investigate the g problem. 'This work request was not pursued ~until the forced plant 1 outage in April 1990. Maintenance I&C found-the valve would not fully a

i open. It was observed that the calibration switch arm looked out of

' place on the electrical position indicator. A measurement of 3 44" -'

was made on the can spindle movement.- The correct movement should have been 3 88". The ratio of these two values indicated that the valve _was only mechanically stroking 88% full open. After L

confirmation of the actual stroke dimensions, I&C set the valve for l o '0-100% full stroke by reducing the spacer thickness behind travel stops in the valve body, b Subsequently, Deviation Event Report (DEH) 90-0264 was written to evaluate the restricted opening of the' east turbine bypass valve. 4 An accountability meeting was held on June 1,1990, to discuss the i: problems-surrounding the east turbira bypass valve overhaul and the l

corrective actions required to ensure proper performance and oversight 19 of future work activities. The root cause of the inadequate b  : maintenance of the east turbine bypass valve was a breakdown in the j ,work package development, implementation, and control process. The

l. following factors were identified as contributing to these failures:

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NRC-90-0112 Page l (1) Inadequate work package preparation:

The time allotted (5 weeks) for work package preparation by the vendor was underestimated.. In the development and review of the work package by the maintenance planners, the turbine outage i; manager, and the English Electric vendor represente' c. an

\ ' incorrect maintenance procedure' for the rebuild of the valve was referenced. However, the correct procedure was subsequently used-in-the actual performance of the job. All applicable drawings were not referenced in the work package. Specifically, the drawing that-provided appropriate-valve setup and stroke critical Aolerances following valve reassembly das neither referenced in or part of the work package. Sufficient rteps ;o properly reassemble the valve were not included in the work package. -

(2) Technical expertise lacking:

1 Detroit Edison and Westinghouse personnel wwe not familiar with the valve reassembly process. As part of tne overhaul of this valve, the original valve stem was replaced like-for-like with a new valve stem from the manufacturer. The valve-stroke was acceptable without'the actuator in place. Once the actuator was reinstalled, it was not recognized that valve disc travel was limited. Detroit Edison and English Electric engineers were both on.the job to provide technical expertise and specific guidance on any critical work being performed. However, this technical

. oversight was insufficient to preclude the event.

(3) Missed. Quality Assurance / Quality Control (QA/QC) holdpoint:

The failure among craft personnel to contact QA led to the missed QA-. hold point. The holdpoint in the turbine generator and valve--

work packages was a generic holdpoint to " notify QA prior to start

=of work and any rework, repair, or parts replacement to allow an asicssment for any further holdpoints." This generic holdpoint was made with the knowledge that roving inspections /surveillances would be performed throughout the. turbine outage. An assumption was made that there was defense in depth on the job site due to F.: inel coverage of the work process. A specialized turbine r% 11 team,.along with Westinghouse, Detroit Edison, and English Eh *;1c engineers should.have provided sufficient oversight to p M ude any problems. With the turbine reassembly complete, it

't ws ucided to waive the missed generic holdpoint (i.e., not perform any further inspections) and use other criteria established in the performance of normal Post Maintenance Testing si (PMT) to verify that all work was performed correctly, i

I (4) Inadequate PMT:

Some PMT was specified in the main turbine work package which also applied to the turbine valve work. However, the PHT was not adequate in that it did not specify either stroke or calibration checks of the bypass valve. Instead, the valve stroke was

-verified by'an operations' surveillance to clear restart l

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restraints at the completion of the refuel outage. This; surveillance test failed initially'because full stroke could not

- be achieved.; Maintenance I&C was contacted and performed. a required;PM which consisted of the calibration of the bypass valve

' indication circuit. The "as found" data did not meet the acceptance criteria. Maintenance I&C incorrectly interpreted the i

data as being a position indication ~ problem and recalibrated the-analog indication.- Operations again performed-the surveillance; this time satisfactorily. Maintenance I&C workers performing the PM did not know that the bypass valve had benn overhauled and it  ;

was not. understood that they were troubleshooting a problem with j I

-the valve operation.

Corrective Actions Taken and the Results Achieved:

- On June 1, 1990, an accountability meeting as held to discuss the improper practices employed during the east turbine bypass valve overhaul,.to~ establish responsibility for this work not meeting i acceptable standards, and to decide on the required corrective actions to prevent recurrence. Improvements in work package preparation were .

identified including the time allotted,_ format, technical adequacy, QA verification and incorporation of lessons learned. A review of RF01 turbine work packages to. identify-where additional controls should be placed~in similar future RF02 packages was conducted. Sufficient management and technical oversight of such jobs will exist during

=RF02.

Work packages for equipment which is either safety related, important

- to safety, supports safety equipment, or performs a function which satisfies assumptions made for a design basis transient were reviewed '

to estabiish a sound level of confidence that RF01 work activities completed on this equipment were performed to acceptable standards.

L Corrective Actions to be Taken to Avoid Further Violations:

I Maintenance procedures and I&C calibration documents for the- turbine

! bypass: valves are being revised based on the review of the RF01 work packages. To preclude similar problems from occurring with the main

/ steam:stop and throttle valves and the low pressure turbine stop and L

intercept valves, those maintenance procedures and'I&C calibration l ' documents are also being revised.- The revisions will include: (1) l additional, technical inspection points with acceptance criteria; (2) reassembly instructions for dimensional checks and correct setting of components prior to fitting; and (3) final stroke checks to verify full design valve travel.

To allow for adequate review with respect to content and time, the

[ process of turbine generator work package preparation is scheduled to commence at least three months prior to RF02. The list of reviewers  !

will include Detroit Edison maintenance and technical engineering personnel. _ As part of this review process, the packages will be scrutinized for the correct identification of technical inspection points.

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. Encloruro to-4 . , NRC-90-0112 Page 5 Development of disassembly / reassembly work packages for all major.

turbine generator components is to be made available prior to the next scheduled major overhaul activity. ,

T At the pre-bid meeting with prospective contractor manaEement and as ,

addressed in the Detroit-Edison turbine overhaul bid specifications g sent to each vendor, the importance of work package development, assembly, review, and implementation was stressed. Particular.- .c

~ emphasis was placed on the fact that personne1' involved-in these four. 1 stagee,must be qualified and trained to site requirements.

Documentation of personnel qualification and training will' be required prior:to making work assignments. This will provide additional 1 assurance:that technically qualified personnel are assigned to these

. jobs.

An' engineer with specific knowledge of and expertise on the turbine: a generator and auxiliary components is now a member of the maintenance 1

staff. This will provide additional technical oversight of future

. jobs.

The PMT for the turbine bypass valves will be revised in the maintenance procedures to require: (1) valve stroke verification, .

recording of full valve travel, and then comparing. the stroke.with the J given design value; and (2) loop calibration test of the valve position transmitter including three remote position indicators. .This test will require valve stroking and measured set stroke values compared with remote indications for the turbine. bypass valves.

I As requested by the NRC in their cover letter to the Notice of l, Violation,-Detroit Edison's response was to address how'we will ensure effective contractor controls in the future. Detroit Edison

' supervisors will be required.to take a more active role in monitoring

-contractor performance. This increased awareness of daily contractor j activities should allow more opportunity to identify deficiencies as l; they arise and to allow immediate corrective actions to be employed.

< The performance of the contractor will be specifically monitored in (the. areas of job supervision and work package usage and modification.

per Detroit Edison requirements and objectives. The bid .

Specifications emphasize contractor responsibilities relative-to work package developwnt, implementation, and modification.

I p The'Date When Full Compliance Will be Achieved Fermi 2's programs are in full compliance with 10 CFR 50, Appendix B, Criterion V, VI, X and'XI.

K Approval of the maintenance procedures for the turbine bypass valves-( will be completed, as described above, by September 30, 1990.

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Statement'or Violation 90-007-03: y "10 CFR 50,' Appendix B, Criterion XVI,. states in part,that conditions adverse to quality such as failures, malfunctions,

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f defective material and equipment, and nonconformances are' promptly identified and corrected.

Contrary to the_above, on November 23,1989,- the. root cause of a  ;

l condition adverse to quality was not properly determined following y the identification of a malfunction of the east mainsteam bypass

' valve ~during performance of surveillance-NPP-24.109.002.

Consequently the' reactor was operated at power with the bypass-valve capable of only partially stroking."

Detroit Edison Response The circumstances. involved were that Maintenance I&C responded to an

-operations' failed surveillance by performing a PM activity. The PM activity was insufficient to identify that the restricted valve. stroke  !

was a mechanical problem with the valve or valve actuator and not with

-the position. indication instrumentation. Inadequate communication t that the valve had been' overhauled and that I&C would be N oubleshooting a'valvo problem is identified as a contributing factor- ,

co-not promptly determining the root cause of .the bypass _ valve restricted stroke. .This was an isolated work request implementation and review problem and'not.a deficiency in the DER process. ,

Corrective Actions Taken-and The Results Achieved:

A dual indication was noted at the time the valve was being stroked-in December, 1989. A work request was' written but not worked until the  :

. forced outage in April, 1990. By reducing the spacer thickness behind L'

the travel stops. in the valve body, the-valve was' able to be ' set to- ,

full'etroke. ,

l The ability.to fully open the bypass valves and the amount of steam 1 these valves can pass is considered in the UFSAR, Chapter 15, j transient analysis. -As a result, Nuclear Engineering performed a review of the operability of the east turbine bypass valve. The

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operability question covered two Teuhnical Specification issues. The first Tech. Spec. issue addressed the setpoint at which activation of the Reactor Protection' System (RPS) occurs after a turbine trip. That i

! esetpoint is 154 psig first stage turbine pressure. The degraded il turbine bypass system was evaluated to ensure steam flow would be

. adequate. The calculated design flow of the degraded bypass valve at 88% open showed it'could pass flow at 1.66 million pounds per hour

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.(mpph), down from 1.858 mpph at 1C0% onen. The capacity of the two bypass valves as a whole would have be(n 3 52 mpph, which would be the amount of' steam produced by a 194 psig turbine first stage pressure.

This is well above the Tech. Spec. setpoint of 154 psig.

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The> second issue addressed the potential for. violation of the Minimum

' Critical Power Ratio (MCPR).- - The Tech. Spec. MCPR was baser on an

-assumed perfset: bypass system. .The degradation of thes east bypass-g- valve meant a total flow change from 3 716.epph to 3 52 apph for the t

system._ : This deviation is _ small enough not to' impact the transient -

analysis in UFSAR Chapter 15.

Corrective Action to be faken to Avoid Further Violations: .s 1he ' loop . calibration test documents for each valve are being; revised to verify actual mechanical valve position or percentage valve stroke ,

nu 'txi be used as the input to the loop and compared to.a percentage 1

,' reading on-the-indicators.

i The Date 7nen Full Cdapliance Will Be AcNieved:

Fermi 2's corrective action progran is currently in full compliance with 10 CFR 50, Appendix B,. Criterion XVI. The date of approval for the revised'I&C loop test douuments is August 31, 1990.

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