ML20236S881

Task Force Review of Equipment & Maint History for Lacrosse

ML20236S881
Person / Time
Site:	La Crosse File:Dairyland Power Cooperative icon.png
Issue date:	12/05/1986
From:	Kanter L, Leemon R, Schweibinz E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
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ML20236S850	List: ML20236S848 ML20236S881
References
NUDOCS 8711300158
Download: ML20236S881 (16)

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{{#Wiki_filter:i f ~; r u o RE&ICW 5 TASK FORCE REVIEW OF EQUIPMENT AND MAINTENANCE HISTORY FOR l LACROSSE REPORT DECEMBER 5, 1986 Task Force Members: E. R. Schweibinz (Team Supervisor) R. J. Leemon (Team Leader) P. L. Eng L. E. Kanter 8711300150 870217 PDR ADOCK 05000409 4 p PDR 1

s O .o ~ 1.. ' TABLE OF CONTENTS Pace EXECUTIVE'

SUMMARY

3 C 1. INTRODUCTION 4-

11. REVIEW METHODOLOGY-5 111. POTENTIAL PROBLEM AREAS REVIEWED FOR TREND ANALYSIS 6'

A. LICENSEE EVENT REPORTS 6 1. INTRODUCTION 6 2. GENERAL

SUMMARY

6 3. CONTROL ROD DRIVE SEAL LEAKAGE 7 4. STATIC INVERTER 1A 8 5. NUCLEAR INSTRUMENTATION 8 6. UNSAMPLED WASTE' WATER TANK DISCHARGE 9 B. INCIDENT REPORTS 9 C. MAINTENANCE 10 D. QUALITY ASSURANCE 11 E. HF.ALTH PHYSICS 11 F. TRAINING 12 G. TRENDING ANALYSIS 13 H. NRC DAILY REPORTS 13 IV. NRC PERCEPTION OF LACROSSE 14 V. LICENSEE SCRAM REDUCTION 15 VI. CONCLUSIONS 16 TABLES:

1. Lacrosse Pecurring LERs by System 6

2. Lacrosse Personnel Errors by Department 7

3. Comparison.of Personnel Errors Resulting from LERs and irs 9

4. Scram Trends 13 LACBWR Letter to Region III did 08/05/86

Attachment:

2 l'

,m. LJ LJ 'e EXECUTIVE SUKv.ARY Region 111 formed a special task force on July 15, 1966, to review the equipment performance of the Lacrosse Nuclear Plant. In response to the high number and increased frequency of plant scrams that had occurred and because of associated equipment problems, the purpose of this review was to determine if any problem areas existed which had not previously been addressed by the NRC and the licensee. A two-year time period (Mid 1984-Mid 1986) was reviewed. The task force determined that: 1. Analysis of the LERs indicated that four systems have been repeatedly involved in reportable events. 2. The licensee is taking appropriate steps to preclude re-occurrence of these events. 3. The licer.see is actively taking steps to reduce the number of scrams. 4. No problem areas existed which had not previously been addressed by either the licensee and/or the NRC. l ) i l 3 l

9 9 .h. 1. INTRODUCTION On July 15, 1986, Region 111 formed a special task force to perform an in-depth review of the equipment and maintenance history for the. Lacrosse Nuclear Plant, with emphasis on identifying potential problem areas or any trends that might exist. -The task force consisted of two resident inspectors, one regional inspector, and the Chief of the Technical Support Staff (TSS). The methodology to perform the review was two-part: (1)toreviewa variety of hard data concerning maintenance history and hardware problems (including assessment of root causes and other contributing. factors)- for potential trends, and (2) to assess NRC and licensee perceptions of the Lacrosse facility via interviews with regional pe. sonnel and licensee personnel to ascertain if potential problem r areas existed that were not identified during the hard data review. It was decided prior to the review not to concentrate effort in the area of. operations since nothing indicated that there was a problem in this area. This task force subsequently completed its review on . September 26, 1986, and this report is a compilation of the observations made and conclusions drawn by the team. 4

Ig. ' "- g-4 ( ' ~ 11. REVIEW METHODOLOGY During the review process, the task force examined both NRC and licensee documents for any potential' trends. The time fra:ne these documents addressed was from July 1, 1984, to June 30, 1986, and included: Licensee Event Reports (LERs) Incident Report (irs) Maintenance Records NRC Inspection Reports NRC Daily Reports Licensee QA Audit. Reports In addition, the following NRC staff members were interviewed by team members for their perceptions of LACBWR'S performance:

1. Villaiva, Senior Reactor Inspector - Lacrosse R. A. Hasse,' Reactor Inspector S. G. DuPont, Reactor Inspector F. Hawkins, Chief, QA Program Section

1. N. Jackiw, Chief, Projects Section 2B D. E. Jones, Reactor Inspector P. L. Eng, Reactor Inspector, (Also member of task force)

Interviews were also conducted with LACBWR personnel of various seniority levels in several departments, ' including Mechanical Maintenance (MM), Instrument and Control (I&C), Operations, Electrical, and Quality Assurance (QA). The. licensee personnel interviewed were asked to describe their position in the plant organization and to discuss their background and experience. The team members generally used questions from the maintenance survey from NUREG 1212. " Status of Maintenance in the U.S. Nuclear Power Industry 1985," as the basis for discussions with members of the licensee's staff. The responses to the' questions were representative of those expressed by the r,ajority of the rest of the industry. l l I 1 ) ) I i 1 5

n .o u O-1 ) 111. POTENTI AL PROBLEM AREAS REVIEWED FOR TREND ANALYSIS A. Licensee Event Reports 1. Introduction Licensee's Licensee Event Reports (LERs) generated during the I period July 1, 1984 through June 30, 1986 were reviewed to determine whether unidentified trends or repeated failures existed which indicated deteriorating plant equipment or other conditions that were not appropriately identified or addressed i by the licensee. 2. General Summary For the period of interest, there were 53 LERs. The distribution shows an upward trend in 1986, and is as follows: i July 1 - December 31, 1984 14 January 1 - December 31, 1985 20 January 1 - June 30, 1986 19 Analyses of the root causes for the events revealed that four systems have repeatedly been involved in reportable events as tabulated in Table 1. It should be noted that in some cases several occurrences are reported in the the same LER. These I systems are: control rod drive seal leakage electrical problems related to Static Inverter 1A scrams due to noise spikes on the nuclear instrumentation unsampled waste water tank discharges Detailed discussions on reports for the above systems are set forth in subparagraphs 3, 4, 5 and 6 below. Aside fror personnel error and the four tystems described above, additional recurring component or system problems were not identified. Analyses of the LERs reviewed and discussions with members of the licensee's staff, indicated that the bulk of events are due to the age of plant components. TABLE 1 LACROSSE RECURRING LERs BY SYSTEM System f LERs ('84) t LERs ('85)

1. LERs ('86)

Control Rods 1 5 1 Nuclear Instrumentation 2 2 1 i l Static Inverter IA 0 0 4 Waste Water Discharges 0 1 3 1 Total LERs for period 14 20 19 6

O-o Table 2 summarizes the; personnel errors as reported via LER by department'. This Table indicates an upward trend of the number of personnel errors in-the first half of 1986, although the numbers are small, making it difficult to draw broad conclusions.- TABLE 2 LACROSSE PERSONNEL ERRORS BY DEPARTMENT

1. LERs
2. LERs
3. LERs I

Department (2nd half of '84) ('85) (1st half of '86) j Operations 3 4 4 Instrumentation and Electrical 1 2 1 Mechanical Maintenance 0 0 1 Health and Safety 1 0 0 Total # of personnel errors 5 6 6 3. Control Rod Drive Seal Leakage I Lacrosse uses a control rod drive system consisting of an upper and a lower drive mechanism. Discussions with rembers of the licensee's staff indicated that a preventive maintenance program was in place for the lower drive mechanism only. Of' the LERs reviewed, only one was attributed to the lower control rod drive mechanism. Review of those LERs associated with the control rod drives revealed that the majority of the events were due to seal leakage from the upper control rod drive mechanism. Leakage can occur at one of two locations: at the flange where the upper mechanism is bolted to the bottom of the reactor vessel and at the mechanical seal on the lower portion of the upper mechanism where seal injection is provided to cool the i upper drive mechanism components. The licensee stated that during the course of repairing or replacing an upper drive mechanism, maintenance personnel receive doses between 2.0 to 4.0 Rem. This high dose is largely due to the close i physical proximity of the control rod drive mechanisms and the necessity of actually removing ceveral other drive i mechanisms in order to gain access to the CRD of interest. Since the dose rates are high, the licensee stated that upper f control rod drive mechanisms were run to failure as oppcsed to being subjected to preventive maintenance. It was noted that two of the LERS associated with the control rod drive mechanisms appeared to be the result of inadequate vendor inspection of the rod drive mechanism prior to delivery to the licensee. 7 \\

W i () tv In an effort to minimize down time for maintenance, the licensee has procured sufficient spare parts to support replacement of all ) the control rod drive mechanism parts and upgraded the materials l of said spare parts wherever possible. The licensee provided trend analysis records related to the mechanical seal failures for the upper drive mechanism and l could not identify any trend with regard to those drive i mechanisms which fail. Failures do not appear to be dependent i of drive age, location in the core or number of scrams. It was noted that the majority of scrams resulting from control rod drive mechanism problems were attributable to Lacrosse's scram logic during startup. Reactor scrams are generated on a 1 out of 58 logic.. Low drive gas or oil pressure on one control rod is capable of generating a partial reactor scram signal at low power. The partial scram signal results in the insertion of half the control rods into the core regardless of reactor power. The licensea stated that an evaluation was being performed to investigate the financial and technicel concerns associated with modifying the logic and imparting more diversity and redundancy. 4. Static Inverter IA The 1A static inverter was installed in 1977. The root cause of the events reviewed was attributed to inverter malfunctions complicated by degradation of the electromechanical relays in the 1A inverter which transfer the load from the normal to the alternate power supply. This concern had been addressed by the licensee as evidenced by the receipt and installation of a new solid state inverter on August 29, 1986. Licensee experience with the IB and 1C inverters which are identical to the new 1A inverter indicated that the problems noted in the LERS associated with the 1A inverter will be alleviated. 5. Nuclear Instrumentation Analyses of those events resulting from problems associated with the nuclear instrumentation (NIs) revealed that the root cause was due to momentary spikes on the NIs. The licensee stated that due to the age of the currently installed system, an excessive amount of noise is periodically experienced in the system. The scram logic at Lacrosse is such that a spike on 1 out of 2 channels regardless of the source will initiate a scram signal at reactor power levels below 151. No provision for advance notification (i.e., control room annunciator), of a scram signal on one channel exists at Lacrosse. This differs from the logic employed at larger boiling water reactors at low power levels in that EWRs typically use a 1 out of 2 taken twice scram logic, and a spike on one channel is annunciated in the control room at which time the operators can bypass that channel and continue to operate. 8

V ". o 9 y-The licensee' stated that a new nuclear instrumentation system had been ordered from General Electric; delivery of the new system is expected in December 1986. Installation of the new system is scheduled for the 1987 refueling outage. The licensee acknowledged the fact that the problems identified by the LERs would not be alleviated until the new nuclear instrumentation system was received and installed. 6. Unsampled Waste Water Tank Discharges Three of the four unsampled waste water tank discharges reviewed, occurred in 1986. Of the three, one was attributed to a random failure of a valve. The other two were both due to either operator error or operator negligence. Discussion with the senior resident inspector.and review of his evaluation of these events indicated that the concern of unsampled waste water tank discharges was being adequately followed. The licensee stated that.they were aware of the repetitive nature of these events and were in the process of identifying appropriate corrective. actions to alleviate this concern. Lacrosse inspection report number 50-409/86-006, documents in detail the history of waste water tank discharge deficiencies and indicates that closure of the pertinent LERs is dependent on review of the licensee's corrective actions. l B. Incident Reports A review of licensee generated incident reports (irs) was conducted for the' period July 1, 1984 through June 30. 1986 for the purpose of trend analysis. Incident reports are used by the licensee to document conditions which are abnonnal and may or may not result in an LER. Analyses of the irs reflected the trends identified by analysis of the LERs. No other definite trends were found other then the upward trend of irs in 1986, most of which were due to equipment problems. Comparison of those irs and LERs resulting from personnel error are as tabulated in Table 3. TABLE 3 COMPARISON OF PERSONNEL ERRORS RESULTING FROM LERs AND irs Period Total t LERs due to Totalt irs due to of LERS personnel error of irs personnel error

• 7/1 - 12/31, 1984 14 5

29 5 1/1 - 12/31, 1985 20 6 40 5 1/1 - 6/30, 1986 19 6 50 4 excluding those which were reported as LERs i 9

4

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b C. . Maintenance The maintenance staff has' received an abnormally high amount of exposure this year. Only four of the ten men in the mechanical. maintenance department are allowed to do any job in a high ~ radiation area for the rest'of 1986 due to cumulated. doses. The contributing factors appear to be the annual refueling outage compounded by an unexpected outage to replace a section of decay heat suction line piping. All plant personnel may have to participate in doing maintenance because of the size of the maintenance staff and the cumulative exposure that they have received this calendar year. This may present a problem for the LACBWR staff to ensure that the personnel are qualified to do the assigned maintenance activities. On a positive note, the turnover rate of plant personnel has been low. Typical plant practice is to repair equipment before it becomes inoperable. Even though LACBWR is of an old vintage, approximately 851 of the time they are able to procure an original replacement part. The remainder of the time they procure an improved part, a new piece of equipment, or a new part is manufactured for the job. A' tour of the warehouse was conducted to review their part locating._ system. With the use of microfilm records and system and component ~ description, parts can readily be obtained. The backlog of work requests was about ten. This is considerably less than the industry average. Through a review.of completed maintenance requests, a concern was identified regarding statements i under. " Repair / Work Performed" which were of ten too brief to give a good understanding of what corrective action was implemented. Through interviews on this subject, it was found that more l information was known than documented. There were no equipment out-of-service tags in the control room and j only a few tags were found in the. plant. There is little or no supervision during maintenance, or second verification that a given job was done right. Sometimes, this was because there is limited space to repair some equipment or ALARA considerations. However, a supervisor was available to answer questions or provide guidance if a problem arose. Supervisors appeared to be confident-in their employee's work anc experience level, expressing that supervision at the job site was rarely necessary. Individuals with less senior status, in a training capacity, expressed that they received more supervisory attention at the work location than those of senior status. 10

O Q b Independent verification af ter completion of the work appears to be lacking. Even though work request forms have an area for i documenting a verifying signature, this appears to be used by the-individual doing the work for documentation purposes' as opposed to actual independent verification. For the areas reviewed, there was no regulatory requirement for independent verification. However, this is a good practice which should be considered by the licensee. None of.the areas reviewed indicated the lack of independent verification resulted in an equipment malfunction. D. Quality Assurance l The activities of the Quality Assurance staff as they relate to maintenance.were reviewed. The QA Supervisor or an engineer determines where hold points are being placed on a case-by-case basis. There is no written guidance to ensure that hold points will be assigned during the required I steps.of construction or repair to ensure quality. No problems were identified where lack of a QC hold poiM resulted in an equipment malfunction. QC personnel do not always evaluate or witness the jobs that are done in high radiation areas or where there is little room at the job location to observe. Team members reviewed the following for equipment or maintenance problems: a 1. Quality Assurance audit reports: Audit.70-85-2, dated 11/15/85 " Emergency Planning" Audit ti0-85-2, dated 7/10/85 " Instrument and Electrical Maintenance". Audit 50-86-1, dated 5/27 through 6/6/86 " Mechanical Maintenance". Audit 02-85-7, dated 12/2/85 - 12/30/85 " Operations" 2. Substitution request " Upper Control Rod Drive Mechanism (10 CFR 50.59) Review" 3. " Quality Assurance Inspection Report" - Upper Control Rod Drive t13 The team members found no trends or areas of concern with the above. E. Health Physics The activities of the Health Physics staff as they related to maintenance were reviewed. Interviews with plant personnel and observations during a guided plant tour revealed the following: I l 11 I _________________n

M1 1 O o. Somt of the licensee's staff have become relaxed in their attitude toward radiation protection practices; such as, going'into high radiation areas without meeting all the requirements of the Radiation Work Permit (RWP). This and several other concerns were discussed with the Region Ill Facilities Radiation Protection Section and the results of their inspection are documented in Lacrosse inspection report number 50-409/86012. It may be necessary for the licensee to review their training for the licensee's controlled area eccess program for the plant staff. The licensee seldom uses mock-ups to reduce exposure. The chemical cleaning of systems to reduce radioactive crud accumulation was cancelled due to lack of funds. .The Radiation Protection (RP) department has computerized employee dose rate histories. The dose rate history was used to assist in planning' maintenance activities. F. Training A separate training department does not exist. The " Assistant to the Operations Supervisor and Training Supervisor" also serves as the supervisor in charge of training. A training specialist has I been selected whose primary responsibility at present, is to develop an INPO accreditation program. These two individuals do not work for the same department. Maintenance qualification cards are being developed, however, it is not anticipated that they will be used in the near future. The maintenance department has developed video tapes on reactor head removal and for the disassembly and reassembly of the upper and lower CRDMs for training purposes. As each video presentation was 1 made, the quality of the tapes improved. The tapes are informative and f airly comprehensive in nature. The use of video tapes as a training tool should also help reduce exposure by familiarizing personnel with the physical location and constraints associated with a given job. The team discussed the information that was presented by the licensee during the site orientation and security training and came to the following conclusions. The security training was I well done and remained consistent between presentations. A check list of items to discuss was used to ensure consistency. The site orientation did not have the same degree of consistency. 1 Consideration should be given to using a checklist, having it videotaped, or some other means to ensure consistency. The Kv.,1&C, and electrical departments had in-house training in conjunction with apprenticeship training. Craft apprenticeship training was given at a local technical cer,ter offered by the state. l l 12 j l

V M -{ G. Trending Analysis The team members performed an analysis of mechanical maintenance work completed on the CRDMs to determine if there were any trends in terms offrepetitive equipment or component failures. No trends were identified as a result of this review. Documentation reviewed for trends was available, however, it was not readily attainable without reference to several documents. An analysis of the LERs for the 23 Scrams during the 24 month time frame of July 1, 1984 to June 30, 1986, indicates'the following: TABLE 4 SCRAM TRENDS Last First Last First Total Half Half Half Half Mid 84 to 1984 1985 1985 1986 Mid 86 Equipment 3 2 3 6 14 Per. Errors 3 2 2 2 9 1 3 7 Noise 3 2 2 0 4 CRD < 1% Power 3 1 2 5 11 > 70% Power 3 3 3 3 12-Scrams related to equipment problems were trending upward Scrams at low power were also trending upward Scrams related to CRD problems are trending downward H. NRC Daily Reports l I Region 11] daily reports for mid-1984 to mid-1986 were reviewed as an additional source of information. This review confirted information discussed in other parts of this reports The analysis of the 23 scrams as described in the daily reports indicated that IE were caused by equipment problems and 5 by personnel errors. Review of the LERs revealed that an additional 4 scrams initially classified as equipment problems were caused by personnel error. This indicates that the licensee is perforning a detailed review of the events and does not improperly attribute all problers to equipment malfunction. 1 l 13 i --..____.__-___J

O o F IV. NRC PERCEPTION Of LACROSSE The team interviewed Region 111 personnel who have had dealings with the plant concerning perceived problems. The consensus of the Region III staff interviewed was that LACBWR has a dedicated staff and that most equipment problems are attributed to plant age, limited plant staff and a limited budget. No other significant concerns were expressed. _r_-

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V. LICENSEE SCRAM REDUCTION 'On August 5, 1986, LACBWR sent a letter (attached) to Region III on the subject of scram reduction. The team reviewed this letter and 'its attached analysis of the 18 scrams in the previous 18 months. The analysis addressed.the actions they are taking which, when complete, should preclude the occurrence of the majority of the scrams. The reviewo'theiranalysisandoftheactionsLACBWRistakingtoreduce scrams indicates that they are appropriate. Some of these actions are as.follows: .l 1. They have purchased nuclear instrumentation (NI) from General Electric to be installed. in March or April 1987. This NI will be state-of-the-art equipment and should avoid several of the scrams experienced in the mid-1984 to mid-1986 period. 2. They are requesting licensing approval to. remove partial scrams and to make some hardware modifications ~ which will cause an alarm when a low gas or low oil condition exists on a single control rod rather than an automatic shutdown. 3. They have replaced the 1A Static Inverter which was the last remaining inverter having an electro-mechanical transfer switch between its principle and backup source..This should reduce the frequency of transfers and also make them noise free. 4. Review of the feedwater pump control problems. '5. Analysis of studies on aging of scram solenoids. 6. Removal of non-essential ' recorders from vital power supplies. I l I 15 -l

l O O VI. CONCLUSIONS There are several conclusions that can be drawn from the data reviewed and interviews conducted during the review process. They are as follows: A. Analysis of the root causes for the LERs reviewed, indicated that the following four systems have been repeatedly involved in reportable events: control rod drive (CDR) seal leakage electrical problems related to Static Inverter IA scrams due to noise spikes on the nuclear instrumentation unsampled waste water tank discharges B. Maintenance personnel have received an abnormally high amount of exposure this year due to the increase in equipment problems. C. Typical plant practice is to repair equipment before it becomes inoperable. D. Analysis of the scrams indicated: a rate of about one per month (23 in 24 months) those related to equipment problems were trending upward those at less than 1% power were also trending upward those related to CRD problems are trending downward E. Licensee personnel have or are taking steps to reduce the number of scrams. Some of these actions are: 1 Purchase of state-of-the-art nuclear instrumentation from General Electric to be installed in March or April 1987. Requesting licensing approval to remove partial scrats and make some associated (logic) hardware modifications. Replacement of the 1A Static Inverter which was the last remaining inverter at LACBWR with an electro-mechnical transfer switch between its principle and backup source. Reviewing feedwater pump control problems. Removal of non-essential recorders from vital power supplies. 16

O o o @DAIRYLAND$@[ COOPERATIVE. r o son e,r. (608) 78E 4:KO . LAMES W. TAYLOR August 6,1986 Genera! Menspe, JR10RITYpeut!Wt p ' 4l &C'" ".C v T as t.1 F3n~; r o ' x l.. y- = $, Mr. James B. Eeppler, Regional Administrator FILQs U.S. Nuclear Regulatory commission 799 Roosevelt Road Glen Ellyn, Illinois 60137

Dear Mr. Keppler:

Scram Reduction, La Crosse Boiling Water Reactor

SUBJECT:

We have been concerned over the frequency of scrams at the La Crosse Boiling Water Reactor which, on the average, occur more frequently here The La Crosse than at other boiling water reactors around the country. reactor, as you know, is a highly sensitive " hair-triggered" reactor designed to a one out of two scram logic which, at the time of its design, was consid-Today, we register concern over frequent challenges to ered a safe option. the plant aafety an'd shutdown system. An analysis of the eighteen scrams which occurred in the past eighteen In this instance, I months of operation has been made by the plant staff. felt it appropriate to share with you an internal communication from the plant manager to me in response to a request for details on the scram causes. The memorandum speaks for itself. I want to point out that several actions have been taken and are being taken to correct aging hardware systems, frequent component failure causes of personnel error. instrumentation to replace the one-out-of-two scram le We expect to install the new instrumentation in the power to flow circuit. A new static inverter has been ordered during the next refueling outage. on an expedited basis to arrive in time for replacement during the current Maintenance items outage for repair of the shutdown heat removal piping. Protection of scram s are being addressed. The training agenda will be modified other contaminants is being reviewed. to address personnel errors, and continued surveillance of scram causes will be maintained from here. On other matters, I'm happy to report resolution of our contentions We have successfully with the State of Iowa Office of Disaster Services. negotiated an understanding of their responsibilities and obligations and our willingness to support financially the services provided by the Iowa State Government for nuclear emergency services. f Q j f)ILJ-Q Q q Q --- _1_

i- [ O O Mr. James B. Keppler August 6,1986 Page t Our entire training program is ready for accreditation review by INPO weeks head of schedule and, we believe, in a complete and acceptable form. We have reorganized the upper management level here at Dairyland, creating an Operations Division and a Technical and Engineering Services Division out of the former Power Group and System Engineering Group. John P. (Jack) Leifer will head the Operations Division, and the Nuclear Plant Manager will report directly to him on administrative and operational matters. The Plant Manager will continue to report to the General Manager on all reguhtory and INPO matters. This means that the General Manager will continue his overview of the nuclear plant from both a regulatory and operat.ional standpoint with day to day details being handled by the Assistant General Manager for Operations, Jack Leifer. At some time in the near future, we will request a management meeting with you, and we will come to Glen Ellyn to review LACBWR operations and directions. At that time, you will have an opportunity to meet new people who are directly involved with our nuclear operations. If you have any questions, comments, or concerns regarding the con-tents of this communication, please let us hear from you. We will respond promptly with the best information available at that time. Sincerely, ff4{h hf JWT/ajm Attachment i cc: John A. Zwolinski Zack Pate, INPO I i

Q [..k.- f .q DAIRYLAND p$@@[ COOPERATIVE MEMORANDUM t ...s o,1,.. [- ) TO: Jim Taylor, DPC General Manager Joe Thie, LACBWR SRC Chairman' ratM John Parkyn,1ACBWR Flant Superintendent SUB,7ECT: Analysis of the Past 18 Months of Scrans at the La Crosse Boillag i Water Basctor 1 1 base reviewed the last 18 months of scrans at 1ACBWR and initiated a data base computer program for future review of a five-year history of scrans at IACBWR and what sort of hardware modification would preclude their occurrence. It should be emphasized that in some cases there are other methods besides hardware modifications which present an alternative path to the ~ hardware modification, however; to determine what would be necessary regardless of Practicality, hardware applications only were considered. I The eenclusions are that of the 18 acrans in the last 18 months (rate of l 12 per year): - 4 incidents could have been avoide6 by the installation of nuclear instrumentation as currently being constructed by General Electric for i the La Crosse Boiling Water Reactor and approved as a 1986 capital expenditure. Delivery is scheduled for September of 1986 and l installation for March or April 1987. The scrams were caused both by l personnel error and by instrumentation spiking on the one out of two j logic. - Esmoving partial scrams will elir.inate four of the scrams in the last 18 months. This is a licensing activity combined with the some han! ware modification which will cause an alare in the Control Rooc when a low gas or lov cil indication is received on a single control red rather than automatic shutdown. This will require operator evaluation and either repair or eventual plant shutdown for repair. One of these scrams could also potentially be eliminated by covering terminal strips. The schedule for removal of the partial scram fumetion is the 1987 Refueling Outage. - Tus scrams have'been caused by the 1A Static Inverter which is the remaining inverter at 1ACBWR having an electro-mechanical transfer l amitch between its principle and backup source. A new 1A Static i inserter with a static transfer switch which should not only reduce the frequency of transf ers between the principle and backup source but make l them scrae-f ree should they occur is currently being purchased. Installation is planned for August 1986 depending on delivery. I f lb val.2 w

ej * ~ w ** [ ' j0, ~. s. 0 \\ a,,.. e, t ..st,8..t.s o,..t e .i,..... , age Three In summary, actions are currently undervey at LAC 3WE to deal with 11 of the 18 ocross by hardware replacement er modification. Once this is accomplished, our next priority will be to review feedveter pump control (2 of the remaining 7 scrams) and to enslyse the results of studies on aging of scram solenoids (an additional 2 out of 7 scrams). This will leave the cause of three scrans during the last 18 months not under consideration for any additional hardware modification. One of these (trip of of fsite breaker) has already had hardware modifications. Another (slow transfer of a breaker to a 2400 volt bus) can only be dealt with throgh the routine braaker maintenance program and one (burnout of SK19 relay) cannot be dealt with practically. As you can see, we have a very intensive program underway and we are very optimistic that with the completion of the modifications already contracted for the plant and the follow-up on the remaining two issues that we can significantly, by the end of 1987 Refueling Outage, reduce our scram irequeocy. JDP/las cc T-5h anAt gg l e e h A A

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