IR 05000271/1993030

Insp Rept 50-271/93-30 on Stated Dates.No Violations Noted.Major Areas Inspected:Licensee Mgt Control Program in Area of Design Change & Mods,Technical Adequacy of Design Changes & Progress in SE Improvement Program

ML20059G459
Person / Time
Site:	Vermont Yankee
Issue date:	01/03/1994
From:	Chaudhary S, Modes M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:
Shared Package
ML20059G446	List: IR 05000271/1993030 ML20059G443
References
50-271-93-30, NUDOCS 9401240167
Download: ML20059G459 (14)

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U.S. NUCLEAR REGULATORY COMMISSION

REGION I

DOCKET / REPORT NOS. 50-271/93-30 LICENSE N DPR-28 LICENSEE: Vermont Yankee Nuclear Power Corporation RD 5, Box 169 Ferry Road Brattleboro, Vermont 05301 FACILITY NAME: Vermont Nuclear Power Station INSPECTION AT: Vernon, Vermont and King of Prussia, Pennsylvania INSPECTION DATES: Vernon, Vermont (November 16-19, 1993)

King of Prussia, PA (December 17, 1993)

INSPECTOR: b /!3!9f Suresitt*tmTdlEry, Sr. Reactor Engineer ' Ilate Materials Section, EB, DRS APPROVED BY: / [

Michael Modis, Chief Dat6 Materials Section, EB, DRS 9401240167 940107 1 PDR ADOCK 0500 G

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.. -l 2 l Areas Inspected: An announced inspection of the licensee's management control program in l the area of design change and modifications; technical adequacy of design changes; progress i in the safety evaluation improvement program; and the overall effectiveness of the licensee's !

engineering organization to provide effective engineering and technical support to plant ;

operations to assure .s afety,  !

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Results: The licensee's engineering and technical support program is satisfactory. The 'l~

licensee has implemented several new initiatives to further strengthen these programs No violations were identifie !

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DETAILS PURPOSE AND SCOPE The purpose of the inspection was to determine the effectiveness of the licensee's engineering organization in providing engineering, technical support, and guidance to the plant to assure safety. The scope included design changes and modifications implemented by the licensee within the scope of 10 CFR 50.59, the licensee's organizational structure, adequacy of staffing in the engineering area, and overall management attention and emphasis on the role of engineering in assuring and maintaining the design basis, including configuration control;-

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and the safe operation of the plant systems (including improvement in reliability and safety performance of plant systems). FINDINGS Organization The licensee's engineering activities, including design change, to assure safe plant operation and day-to-day engineering support is provided by the plant engineering organization located at the plant site. This group is involved in less complicated and routine safety evaluations and engineering analyses of an urgent nature to support plant operations. Minor modification ,

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and system analysis, and evaluation of performance data are also performed by the site cugineering grou '

- A separate group of design engineers is responsible for long-range planning of modifications, performing indepth safety evaluations, engineering analyses for design changes, safety improvements, and maintaining the design basis of the plant. This group is located offsite at Bolton, Massachusetts, and is part of the Yankee Nuclear Services Division (YNSD).

The onsite engineering and technical support group reports to the Vice President of Engineering (VP-E) through the engineering director, and the VP-E coordinates the work of the plant engineering and YNSD engineering group using a relatively small engineering staff at the corporate headquarters in Brattleboro, Vermont. The corporate engineering staff is also engaged in design basis reconstitution and probabilistic risk assessment effort !

The plant engineering department consists of three groups, each headed by a supervisor. The three groups are: 1) Electrical Engineering and Construction; 2) Technical Programs; and 3)

Mechanical Engineering and Construction. The electrical and mechanical groups include instrumentation and control, and civil / structural expertise, respectively. The technical  !

support group provides services in the area of fire protection, design and drafting, and i industry experience coordinatio l i

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4 Staffing There are approximately twenty-five engineers and support personnel assigned to the engineering department at the site; twenty are permanent plant employees and five are contract engineers. There are about five engineers in the corporate office as the VP-E's staff. Additionally, there are a number of engineers assigned to the Vermont Yankee project q team at the YNSD offices in Bolton, Massachusetts. This offsite engineering staffis supervised by a YNSD project manager, and is supported by other specialist groups within YNSD and contractors as neede .2.1 Technical Training

- The licensee continues to have a broad-based administrative and technical training program for the site and corporate engineering staff. The training is grouped under three general areas, i.e., core training which is required of all engineering personnel at the time of initial employment, and position specific training which is related to an individual's assigned jo ,

The third group is elective training which is chosen by the staff and approved by the i functional superviso l

'l Based on discussions with the engineering staff and supervisors, the inspector found them to l be technically knowledgeable and familiar with the areas of their responsibility. The training program developed to address training needs of the engineering / technical staff was comprehensive and appeared effective for engineering assignments. The inspector had no further question in this are I 2.2.2 ' Communication / Interfaces i An effective interface exists between the operations and engineering personnel at Vermont j Yankee Nuclear Power Station. This was evidenced by the daily morning meetings of l operations, engineering, and other support organization staff. Effective interface amongst the site engineering, operations, and maintenance groups was enhanced by the participation in these meetings of supervisory and management personnel from those organizations. The plant managers meeting was effective in resolving interdepartmental problems. The engineering scoping meeting for design change and modification planning was '

interdepartmental and multi-disciplinary in nature. Furthermore, the weekly Plant Operations Review Committee's (PORC) meeting, and the bi-weekly plant manager's meeting contribute to resolving technical concerns and prioritizing wor l l

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t Engineering Backlog A review of the engineering project list indicated there was no backlog in the priority ,

projects slated for the 1993 outage. The engineering and operations department jointly agree on the priority of any planned or recommended modification. There are three levels of priority designated as one, two, and three (1,2, and 3). The first priority (1) is assigned to work which is either mandated by new requirements (e.g., NRC bulletins or generic letters)

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or plant and safety improvements indicated by operating data or industry experience. The second priority is assigned to other plant improvements related to efficiency, economy and -

for ease of operation. The third priority consists of either convenience and other " nice-to-do" improvements and facilities. The inspector noted that there was no backlog or postponement in any priority "1" work scheduled for the 1993 outage, and priority 2 or 3 work was also largely accomplished. The licensee's policy of completing all planning and design work at least six weeks before the planned outage was effective and had contributed to ,

the successful adherence to the schedul .4 Engineering, Planning, and Control of Modification and Design Changes

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To determine the scope, depth, and quality of engineering effort involved in the design _

changes and modifications, and the licensee's engineering organization's effectiveness, the inspector reviewed the engineering design change process implemented by the onsite and offsite engineering groups. Based on this review, discussions with cognizant personnel, and personal observation, the inspector noted that the licensee had initiated a comprehensive ,

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review and assessment of design change and modification procedures. The effectiveness of this effort was evident by the revision of procedures affecting design changes, minor modification, modification installation, surveillance tracking, reassessment of 50.59 screening reviews, operating experience reviews and assessment process, and upgrading of the

" scoping" process for proposed modification The items and procedures reviewed in the above effort included: 1) formalization of a self-assessment program; 2) revision of temporary modification (TM) procedure, AP0020; 3)

strengthening AP6000 to emphasize the documentation process; 4) strengthening AP0028 to emphasize evaluation, field verification and the broader implication of operating experience documents; and 5) computerizing the surveillance tracking system to enhance technical and management information for more effective plant operation and maintenance process; and formalizing and improvements in the " scoping" memo process for design change Based on the results of the above effort in the applicable procedures and programs, the inspector determined that the above effort was effectiv l i

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l Control of Temporary Modifications The inspector reviewed the licensee's draft procedure for the control of temporary  !

modifications (TMs). The procedure was to be implemented to define, control, and specify review and approval requirements for temporary modifications to assure preservation of design intent, operability, and plant and personnel safet l The procedure was specific and clear, covered all TMs regardless of the safety class of equipment and item, and established strict requirements for extension of the TM life. Any TM required for more than six months must be reviewed and approved by the POR Effective controls on TMs were exercised by a quarterly review of all TMs for validity or PORC review. The inspector observed that the current control over TMs was clearly an improvement over the licensee's previous TM progra .6 Technical Support to Unplanned Events The inspector evaluated the licensee's engineering organization's involvement in and effective contribution to the non-routine events of the plant operation. By review of Licensee Event Reports, transient analyses, and root cause determinations of unplanned events, the inspector determined that engineering was actively participating, and effectively contributing to the analyses, evaluations, and proper resolution of events and problem The inspector reviewed a selected sample of unplanned work by engineeri .g during the 1993 refueling outag ;

Some of the events reviewed are as follows: ,

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• Dropped fuel'oundle incident investigation, the results of which were used to analyze the root cause of the even l

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• Human factors review of the " refueling-grapple-closed" indicating light, and hoist up/down joystick control operatio * Design of a TM to implement an interlock into the refueling platform to prevent l

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reusing the grapple when loaded, but not close * Suppmt to maintenance in one-for-one replacement of plant equipment, which in many cases irnproved reliability of design over the origina * Repair of #2 A/B feedwater heater shell erosion, which was identified while working on the heater steam inlet nozzles, i

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• Evaluation of the use of RMS-9 breakers, high pressure coolant injection / reactor core isolation cooling (HPCI/RCIC) rupture diaphragm, and the plugging of the residual heat removal (RHR) A heat exchange * Engineering support to maintenance in the startup transformer grounding proble * Core spray suction strainer problem of strainer size, involving an expedited design change package, including fabrication and installatio * Failed air start check valves in the emergency diesel generator The above examples of engineering support to the operation and maintenance department by the engineering organization is a partial list of the records reviewed by the inspecto Based on the above review, the inspector determined that the engineering and technical

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support provided by the engineering group was very responsive to the safety of the outage aud plant operatio .7 Engineering Initiatives MOV Modifications Vermont Yankee Engineering has performed a conservative analyses of operating conditions of motor operated valves (MOV) which potentially could require modifications based on completed design basis reviews done for GL 89-10 and current industry evaluation method This estimate is based on conservative design basis reviews using the maximum design bases differential pressure, information available from the comprehensive design bases reviews in progress, and the industry experience with MOVs and diagnostic testing data gained since 198 Evaluations have concluded that the MOVs are considered operable and able to perform their required function (s); however, enhancements have been completed on some of these valves during the 1993 refueling outage with further enhancements scheduled for valves in the main steam tunnel and drywell during the 1995 refueling outag While the final comprehensive design basis reviews could demonstrate that some of these modifications were not required, Vermont Yankee Engineering proposed that the modifications be completed based on these conservative evaluations to ensure compliance with GL 89-10 within the committed schedul c

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New LOCA Analysis Vermont Yankee completed a new loss of coolant accident (LOCA) analysis using l methodologies developed and licensed by Yankee Atomic. The new analysis incorporates current NRC requirements and directly incorporates instrument accuracies into the LOCA ,

model. The results have shown significant margin between calculated values and NRC '

i acceptance criteria. The maximum peak clad temperature for the current licensing basis LOCA is 1778F compared to the NRC limit of 2200F. An analysis was performed assuming that only one core spray pump or one low pressure coolant injection (LPCI) pump was operable; under these conditions, the peak clad temperature was only 1850 Emergency Diesel Generator (EDG) Service Water Discharge Piping Engineering analyses and data collected from surveillance tests led to the conclusion that there was a significant increase in the pressure drop in the EDG service water discharge piping. Various options were studied and it was recommended that the plant either clean the pipe or replace the discharge line. A decision was made to install a second discharge lin Alternate Cooling System Cleaning As part of the cleaning operation for the alternate cooling system line from the cooling tower '

deep basin, plant maintenance requested a recommendation for an acceptable coating process to be used for the line. Based on their investigations, Engineering recommended that no coating be applied at this time. The basis for this recommendation was a concern that adequate time was not available to properly evaluate the pros and cons of coating system Augmented Off Gas (AOG) System lmnrovements In the past, Vermont Yankee has experienced operational and reliability concerns with the AOG system. This included several occurrences of the bursting of the intercondenser rupture disc. Engineering performed an evaluation to identify where improvements could be made to the system to alleviate this problem. The basis of the improvements were to increase reliability, reduction in maintenance activities and radiation exposure, and the prevention of system transients which could challenge plant equipment. Recommendations included such things as:

• Replacement of obsolete equipment, and equipment whose function can be better performed by present day replacements

• Equipment operation and control changes

• Improvements in system drawings

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• Wiring changes to improve reliability, maintenance and troubleshooting, and to add additional fuse protection e Perform a review to increase circuit reliability to reduce nuisance alarms Based on' this evaluation, Vermont Yankee has presently scheduled a design change to be developed in 1994 to implement one or more of the above recommendation Seismic Unerade Modifications for Diesel Auxiliary Eauipment This design change provides structural modifications to auxiliary components of the diesel generators by enhancing their capability to withstand a seismic event of magnitude greater than the licensed design basis. These upgrades were recommended by Engineering as proactive initiative in advance of the formal implementation of seismic programs to address GL 87-02 and GL 88-20, Supplement RMS-9 Circuit Breakers Shortly before Vermont Yankee's shutdown for it's scheduled refueling outage, YNSD became aware that several breakers, installed with RMS-9 overcurrent trip devices, had spuriously tripped at Maine Yankee. Since Vermont Yankee's electrical distribution system is similar to that of Maine Yankee's, YNSD closely followed the issue and recognized the potential for this problem to affect Vermont Yankee's startup. As a result, YNSD developed an action plan fer Vermont Yankee to preclude spurious trips of their RMS-9 breaker Based on YNSD recommendations, Vermont Yankee performed the following actions: Stopped the scheduled breaker conversion efforts to replace EC devices with RMS- . Upgraded existing NNS breakers with EC-1 to SC . Swapped breakers within the 480 V load centers to ensure that the breakers feeding essential SCE loads were equipped with EC-1 device . Purchased unused breakers from Yankee Rowe and dedicated them to SC YNSD worked closely with the Vermont Yankee Maintenance Department and provided settings for the EC-1 devices to ensure that breaker coordination was maintaine ,

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10 t Flow Assisted Corrosion (Erosion /CorrosioJQ i

. The Vermont Yankee piping inspection program is managed and implemented by the Engineering department in accordance with regulatory guidance documents. This program utilizes the EPRI developed CHECMATE software program to predict, based upon -  !

operational parameters, those piping systems that are most susceptible to erosion / corrosion (E/C) phenomena. These analyses provide input into the selection of components for the ,

inspection scope. Engineering participation in the checkmate user group, CHUG, enhances :

Vermont _ Yankee's program; in that actual industry experience is factored into the inspection scope. All modifications and replacements resulting from inspection activities utilize ,

materials which minimize the effect of the E/C phenomen '

Feedwater Heaters -

Inspections of the balance of plant (BOP) feedwater heaters is managed by the Engineering department. Inspections are performed each outage and the results are factored into  ;

successive inspection recommendations. Techniques include ultrasonic and eddy current .

examinations for shell and tube side inspections. In addition,1993 efforts included ultrasonic

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leak probe testing to locate suspected tube leaks and define a scope for tube plugging activities. An important aspect of the Engineering's initiatives and recommendations in this 4 area have resulted in the replacement of four original heaters with new heaters. Also, efforts to repair or replace heater shells, piping nozzles, impingement plates, and level control '

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systems have been implemented in order to maximize heater efficiency and operating lif Main Generator Excitation System Imorovements After reviewing the performance of Vermont Yankee's Alterrex Excitation System during a 1991 plant trip, Engineering recommended that the excitation system performance should be

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evaluated further. Engineering reviewed the results of the transient with General Electric excitation system experts and recommended that the excitation control system be readjusted and calibrated with special attention to the adjustment of regulator gain, to provide for proper stability. In addition, engineering recommended that Vermont Yankee accept certain excitation system component improvements proposed by G During the last outage, GE implemented the recommendations under the supervision of a l Yankee Atomic engineer. It is believed that this project will minimize undesirable transients on the electric power syste :

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Electrical Engineering Transient Analysis Capability Electrical engineering has developed the ability to perform certain dynamic transient analysis in house in order to better serve the plant. This capability has been used to analyze bus voltage transients during motor starting and in the technical evaluation of replacement reactor feed pump motors. The reactor feed pumps are the largest load on the plant power syste The proposed replacement motors all had different speed torque characteristics, inertias, et The evaluation indicated that one proposed replacement could have accelerated too slowly, tripped, and caused a plant transien .8 Modification / Design Package Review 2.8.1 Reactor Water Level Reference Leg Backfill Modification (EDCR 93-404)

The purpose of this engineering design change request (EDCR) was to resolve a concern regarding the accumulation of noncondensible gases in the reactor vessel water level reference legs. To address this concern, the NRC directed all BWR owners to implement hardware modifications. Specifically, any BWR in a cold shutdown mode would remain so until a hardware modification was in place and operationa Although Vermont Yankee had not experienced this problem, other BWRs had problems with noncondensible gases in their systems. It was Vermont Yankee's belief that the existing ]

reactor water level system was highly reliable and met all design criteria. However, the i licensee deemed it prudent to modify the system by installing a reference leg backfill syste For the raodification, the licensee selected the only design which had been reviewed by the 1 NRC as acceptable, to assure that Vermont Yankee would not be required to demonstrate the l cfficiency of the design and be delayed in startu l l

In reviewing the design change package, the inspector noted that the modification package I I

was well documented and contained a good safety analysis. Technical analyses and design bases were docunented in detail, and the design and operating considerations were logically and clearly laid out. Post-modification testing also was specified in the design change ;

package. The design change and the package was of good technical quality and well controlle .8.2 Diesel Generator Service Water Piping Modification (EDCR 93-403)

This EDCR described the addition of a new diesel generator service water discharge header, _1 including piping and associated valves, and modification of the existing discharge lines. The moclification also allowed for various alignments of the diesel generator discharge through existing and new discharge lines for both EDG units, and EDG 1-A through a new path and EDG JB through an old path, and each EDG individually through either of the common discharge line l

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This modification was to provide additional flow margin to the diesel generators to assure that they were adequately cooled in the event of various postulated accident scenarios. This design change was implemented in the 1993 refueling outag A review of the safety analysis of this modification indicated that this change did not affect j the plant's licensing basis, nor did it adversely affect any of the safety-related functions of the associated systems. The modification package was well documented with engineering

. ses, safety evaluation, and required information for proper installation and operation of .;

tem. The inspector had no further questions in this matter at this tim l 2.8.3 Other Modification Packages In addition to the above reviewed modifications, the inspector also reviewed some other l modification p- mes. The packages reviewed were: 1) PDCR-92-18, Plant Modification Associated wi 11ird Interval ISI Program; 2) EDCR-92-404, RHRSW System Modification /%iated With Valves VIO-89-A and VIO-89 ;

Both of the above modification packages were well documented, including engineering analyses, safety evaluation, and construction / installation requirements. The review by the inspector did not disclose any deficienc l Self A"essment and Audit of Design Change Process l

The inspector .eviewed the audit report number VY-93-07. This audit was performed by the ;

licensee's internal QA department to assess the adequacy and effectiveness of the design l change process, and the self-assessment program developed by the engineering groups withm the engineering departmen ]

Based on the review of this audit, the inspector determined that the audit was comprehensive- ;

and indepth. The conclusions reached in the audits were well supported by the auditors'

observations and documentation, and the audit had significant positive, as well as negative findings. Four deficiencies and five observations were documented in the audit report. The ;

list of participants in the exit meeting indicated that plant management had a high regard for - -

the audit process. This audit confirmed the NRC inspector's general observation that the licensee's engineering management was aware of some weaknesses, but were taking effective steps to enhance the effectiveness of engineering programs, and their internal self-assessment program was providing valuable input in_ this regar ,

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2.10 Conclusions l Based on the above review of documentation, observations, and discussions with management and technical personnel, the inspector concluded that the licensee's engineering programs were satisfactory. The engineering department has effectively implemented a self-assessment -  :

program which provides valuable insight into the program weaknesses before they become a proble-m and negatively impact the plant safet '

In summary, the licensee' design change and modification program is satisfactory, th organizational staffing and interface with other departments and groups are adequate to '

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effectively perform its technical support mission; and to maintain the plan's design basis.-

2.11 Exit Meeting ,

At the conclusion of the onsite inspection on. November 19,1993, and the offsite documentation review and inspection in Region I office at King of Prussia, Pennsylvania on December 17, 1993, the inspector briefed the licensee management regarding the scope and findings of the inspection. The licensee acknowledged the finding :

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NITACIIMENT 1 Persons Contacted Vermont Yankee NucleaLPower Corocration W. Anson Tech. Programs Coordinator Engineering Director -;

B. Buteau R. Clark Director, Quality Assurance

'L. Doane Operations Manager R. Grippardi QA Supervisor R. Pagodin Operations Superintendent W. Peterson QA Manager R. Wanczyk Plant Manager M. Watson IC Manager t

U.S. Nuclear Reculatory Commission H. Eichenholz Sr. Resident Inspector P. Harris Resident inspector S. Hansell Operations Engineer l

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