IR 05000237/1991033
| ML17177A265 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 02/06/1992 |
| From: | Langstaff R, Lougheed V, Phillips M, Salehi K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML17177A262 | List: |
| References | |
| 50-237-91-33, 50-249-91-36, NUDOCS 9202180190 | |
| Download: ML17177A265 (16) | |
Text
U.S. NUCLEAR REGULATORY COMMISSION
REGION III
Reports No. 50-237/91033(DRS); 50-249/91036(DRS)
Docket Nos. 50-237; 50-249 Licenses No. DPR-19; DPR-25 Licensee:
Commonwealth Edison Company 1400 Opus Place Downers Grove, IL 60515 Facility Name:
Dresden Nuclear Power Station, Units 2 and 3*
Inspection At:
Dresden Site, Morris, Illinois; and 1400 Opus Place, Downers Grove, Illinois Inspection Conducted:
December 3 - 31, 1991 Inspectors:
//_/ t w/l.2tA I~--
/v. P. Lougheed
..
! /,,.
~~~{_,t,J,0~.~,> c:A-
,. R. A. L, gs/taff I
.-,~
J/IP) * JA,,T{,/. '(.*-.-*
/*+tU,~/iJ..;'f., k Inspection Summary Date Date 7/t /y-*2 Date 7/;./y* 't_
Date Inspection from December 3 -
31, 1991 Cinspectiom Reports No. 50-237/91033(DRS); No. 50-249/91036CDRS))
Areas Inspected:
Routine, announced, safety inspection of the licensee's engineering and technical support activitie Inspection modules used were 92701 and 3770 Results:
One violation was identified during this inspection regarding the failure to take action to identify the source of the correct leakage into the Unit 3 drywell liner and pocket area and the torus basement (Paragraph 4.A).
In addition to the violation, weaknesses were noted in the following: Communication among groups within the Nuclear Engineering Department did not always ensure that appropriate technical personnel were involved with a projec The handling of the Turbine Building cracking (Section 5) indicated that the right people within the engineering department were not always contacted or utilized for engineering activitie PDR ADOCK 05000237 G
conversely, communications between the technical staff and onsite engineering were goo (Section 6.D.1) In addition to the violation, corrective actions were not always prompt partially due to the lack of adequate trending or tracking of events or component performanc (Section 5.A)
- A large portion of the technical staff were newly hired (within the last 18 months) college graduates with little experience who had been assigned multiple systems without sufficient knowledge concerning the syste (Sections and 6.E) The actions taken concerning the drywell leakage appeared to be contrary to the submitted response to generic letter 87-0 Although the surveillance to assure drain lines were open had been completed and the submittal to NRC indicated leakage would be reported and corrected, drain lines were found clogged and no corrective actions initiate (Section 4)
Specific strengths were identified as follows: The prioritization program for performing modifications was well thought out, workable, and highlighted safety significance for modification performanc (Section 6.B) The onsite engineering assistance and involvement were found to be positive elements of the overall engineering support for Dresde (Section 6.C) The effort to evaluate other CECo and industry events for applicability to Dresden was good, however, not all appropriate people were familiar with this system and its us (Section 6.D) The experience leve+s for the corporate engineers (including those located onsite) were goo (Section 6.E) The Engineering Assurance organization was doing a thorough job of highlighting ongoing problems in the engineering organizatio (Section 7) The comparative audit of all six nuclear sites to identify the "model plant" in a specific area was a good initiative that produced insightful result The technical staff area had been scheduled for such an audit during 199 (Section 7)
2 DETAILS Persons Contacted Commonwealth Edison Company CCECo)
- B. Shelton, Director - Engineering Performance
- C. Schroeder, Station Manager
- B. Adams, Regulatory Assurance Engineer
- S. Berg, Assistant Production Superintendent
- G. Bergan,_Safety Engineer
- K. Deck, Safety Engineer
- R. Dee, Safety Engineer
- L. Gerner, Technical Superintendent
- D. Lowenstein, Regulatory Assurance Analyst
- B. Mayer, Nuclear Quality Programs Inspector
- R. Radtke, Regulatory Assurance Supervisor
- M. strait, Technical staff Supervisor
- T. Tolish, Field Engineer
- B. Viehl, Site Engineering Supervisor
- J. Watson, Nuclear Quality Programs Engineer
- D. Wheeler, Construction Superintendent U.S. Nuclear Regulatory Commission CNRC)
w. Rogers, Senior Resident Inspector D. Hills, Resident Inspector
- M. Peck, Resident Inspector
- D. Liao, NRC Intern
- Denotes those attending the exit interview conducted on December 20, 199 The inspectors also interviewed members of the licensee's engineering and technical staff, quality assurance organization, operations department, and maintenance departmen.
Licensee Actions on Previously-Identified Items (92701) (Closed) Open Item (237/91015-03) "Updating the Process Computer after a Refueling Outage":
The licensee issued a temporary change to procedure DTS 8148 to require the computer to be updated within two weeks after establishing the WTC and WD correlatio A permanent procedure change was also being prepare This *item is considered close (Closed) Open Item (237/91015-01; 249/91014-01)
"Completion of Training Following Modification Implementation":
The licensee held a meeting on August 8, 1991, to discuss the significance of signing
the "training complete" box on modification approval form As a result of the meeting, those who may sign that specific box were advised that when training or notification is required, all specified personnel training or assigned notification must be completed prior to signing the "Training Completed" bo This item is considered close.
Review of Design Changes (37700) Modification M12-3-90-029 "Install Hardened Wet Well Vent":
This modification installed a hardened vent to the primary containment as required in Generic Letter 87-1 The modification added a vent path to be opened prior to reaching maximum primary containment pressur The overall quality of the modification approval letter and safety evaluation was goo They appeared comprehensive and addressed potential effects on system operation In addition, post-modification testing criteria were adequate and addressed system design requirement The inspectors identified a concern with the classification of this modificatio The modification approval letter invoked ASME Section V requirements which were not reflected on the modification installation approval for The licensee agreed to resolve this concer Modification M12-3-88-57 "Replace Actuator for
Feedwater Regulating Valve":
This modification replaced the air Operated actuator on a feedwater regulating valve with an electro-hydraulic actuato The modification was performed to correct control problems experienced with the valve The inspector reviewed the 10 CFR 59.59 safety evaluation and performed a walkdown of 'the installatio No concerns were identifie Minor Design Changes P12-2-89-682. P12-3-89-690, and P12-3-89-691. Torus Wide Range Level Transmitter Replacements:
The licensee was replacing the torus wide range Barton level transmitters with Rosemont level transmitters to correct previous equipment problems and improve replacement component availabilit Both Unit 3 transmitters were replaced during the 1991-92 refueling outag One of the two Unit 2 level transmitters was also replaced, with the other scheduled for the next refueling outag The inspectors reviewed the 10 CFR 50.59 safety evaluation, the instrument accuracy calculation, procurement and receipt inspection information, and the associated calibration procedure for the transmitter The inspectors also walked down the existing instrument lines, where possibl An associated licensee event report (LER 50-249/91-003) was also reviewe The inspectors identified two concerns, one related to the adequacy of the designer's and installer's walkdowns and the other related to the potential for personnel electrocutio Some of the existing instrument lines for the torus wide range level transmitters were incorrectly sloped, and this condition had not been identified by either the designer's or installer's walkdowns performed by onsite engineerin In this configuration, the lines could develop either air or water pockets which would adversely affect instrument accurac The licensee subsequently determined that the accuracy would not be affected beyond that required for design and that no modification of the existing instrument lines would be require The inspectors concurred with the licensee's assessmen T~e inspectors noted one employee safety concern due to standing water in the torus basement and the presence of an electrical outlet box on an extension cord in the standing wate As. a result, one of the sensing instrument lines for Unit 2 was not accessibl This condition was brought to the licensee's attention for correctio Temporary Alterations:
Temporary alterations were controlled by procedure OAP 07-04, "Control of Temporary System alterations," revision 1 The inspectors reviewed the temporary alteration log and noted that the licensee had 47 temporary alterations in place at the time of the inspection, 17 exceeded six months duration, and 7 exceeded one yea Temporary alterations had an extended justification prepared if the alteration exceeded either three months or its original estimated duration.. No concerns were identified during the inspectors review of the safety evaluations, technical justifications, and extended justifications on a sample of temporary alteration.
Drywell Liner Leakage
The inspectors observed water leaking from the Unit 3 drywell liner sand pocket drains and from the vicinity of the downcomer legs into the torus basemen The leakage was estimated, by the inspectors, to be approximately five gallons per minute (5 gpm).
The licensee indicated that leakage was normally present when the refueling cavity was flooded, and that after the refueling cavity was drained the leakage stoppe After reviewing the history of this condition, the inspectors identified three significant concerns:
Failure to take appropriate, timely corrective action
Lack of system engineer experience and familiarity with the system
Lack of management attention to ensure implementation of generic letter response to NRC Failure to take Appropriate, Timely Corrective Action Although leakage in the drywell liner sand pocket region had been observed as early as 1987, the licensee had not initiated a deficiency or nonconformance report nor taken any actions to identify the source of the leak or correct the proble The leakage was significant because of the potential to effect the operability of the primary containment through.
corrosion of the containment line The NRC issued Information Notice (IN) 86-99, "Degradation of Steel Containments," and Generic Letter (GL) 87-05 in March 1987 requesting licensees to address a similar condition which resulted in a significant reduction in wall thickness of the dryw.ell liner at Oyster Cree A supplement to IN 86-99, describing Oyster Creek's corrective actions, was issued in February 199 As part of its response.to the Generic Letter, CECo committed to perform surveillances of the sand pocket drain lines every outage; leakage was to be promptly reported and correcte In addition, in 1988 the licensee performed an ultrasonic examination of the containment and concluded that the containment had not degraded at that tim However, leakage has continued during every refueling outage conducted since that time and has increased from the original "few drops per minute" to the current 5 gp The failure to take prompt corrective action is a violation of 10 CFR Part 50, Appendix B, Criterion XVI, which requires that measures bee established to assure that conditions adverse to quality are promptly identified and corrected (50-249/91036-01).
- Lack of system Engineer Experience and Familiarity with System The system engineer had only 18 months of experience since graduating from college and was not familiar with the issues concerning the leakage proble While the system engineer was aware that surveillances were conducted as a result of an "industry problem" associated with the leakage and that.UT measurements had been taken of the drywell liner, he was not aware that the two issues were related, nor was he aware of either the IN or the G Further, he was not aware of the supplement to the IN which had been issued after he had encountered similar leakage at Unit The system engineer was not aware of the Dresden response to the GL, nor did he know what commitments existed to monitor and correct leakag For example, drain lines remained plugged after the surveillance had been performed which was contrary to the purpose of the surveillanc In addition to the primary containment, the engineer was also responsible for two other major system The inspectors* attributed the engineer's lack of detailed system knowledge to his work load and his lack of experienc * Lack of Management Attention to Ensure Implementation of Generic Letter Response to NRC By letter dated September 6, 1988, the licensee responded to GL 87-05 and stated that surveillances to check for leakage from the sand pocket region drain lines would be performed and "any evidence of leakage through any of the drain lines constitutes an abnormal condition to be reported and for corrective measures to be initiated." In addition, the licensee committed to
- perform ultrasonic testing of the primary containment liner to determine if degradation had occurre *
The licensee did not make any effort to correct the leakag Surveillances of the drain lines during refueling outages were begun in.198 Unit 3 surveillance records showed that leakage had been present since the surveillances were first implemented and had increased every refueling outag Leakage also occurred on Unit 2, although it was less extensive than Unit Although the Unit 3 surveillance was performed prior to this inspection, some of the sand pocket drain lines remained clogged contrary to the intent of the G The inspectors concluded that a lack of management attention had allowed the leakage problem to persis **
Although no deviation or nonconformance report had been generated, despite the fact that the surveillances continued to identify the leakage condition, in December of 1990, the system engineer initiated Action Item Request (AIR) 12-90-07 to corporate engineering to determine the source of the Unit 2 leakag No action was taken on the AIR until September 1991, when the station again encountered leakage during the Unit 3 refueling outage and the system engineer reinitiated the AI The licensee's procedure required issuing a deviation report only for conditions which either warranted a unit to be derated or if a reportable event occurre This threshold for deviation reports contributed to the failure to implement corrective action to prevent continued leakage or ensure that the containment liner was not adversely affecte At the time of inspection, the presence of leakage, identified through the surveillances, had not been reported to the NR The tech staff management and senior plant management viewed that the statement in their response to GL 87-05 did not constitute a commitment to report this leakage to the NR However, based on the inspectors' discussions with NRR, this was not the understanding of the NR During the inspection, technical staff management stated that they considered the leakage only to be a nuisanc This was based on a report prepared in 1988 indicating that.UT results showed no appreciable reduction in thickness of the drywall liner, with some liner plate measurements exceeding the expected tolerance Based on the as-found plate thickness and an estimated corrosion rate of 10 mils per year, the licensee estimated that 27 years remained before liner thickness would be a proble However, the supplement to IN 89-66, issued in 1991, stated that corrosion rates were actually on the order of 35 mils per year at Oyster Cree No re-analyses was performed based on the information provided in the IN supplement or the increasing leakag Conclusion The licensee's failure to initiate corrective actions as required by the regulations.was caused by a lack of appreciation of the issue by both the system engineer and station managemen After discussions with NRC management on December 26 and 31, 1991, the licensee agreed to perform the following actions during the
- Unit 3 refueling outage:
(1) perform UT measurements at 5 of the original 22 sample locations in the containment liner to ascertain the amount of liner degradation; (2) perform a visual inspection, if possible, of the refueling cavity liner to determine the leakage source; (3) sample the water in the Unit 3 torus basement to verify that it was from the refueling cavity; and (4) clear the plugged sand pocket drain line Turbine Floor Cracking During a walkdown in the turbine building, the inspectors found a large crack that could potentially affect safety related equipmen The crack was approximately 1 11 to 1 1/2" deep, consisting of spalled concret The inspectors reviewed the licensee's activities in response to the formation of the crack and identified two concerns:
Corrective action Communication among corporate engineering organizations Although the turbine building is not a safety related structure, several pieces of safety related equipment could be affected by spalling of concrete from the crack, including safety related switchgear MCC-29 and portions of the standby gas treatment syste Corrective Action The crack was first identified by the licensee in April 199 No actions to prevent further propagation of the crack have been taken to dat In June 1991, Sargent and Lundy (S&L), evaluated the cracking and recommended that the outer layer of the cracked concrete be completely removed in order to evaluate the extent of the crackin The licensee did not implement this recommendatio In November 1991, after the licensee noted that the crack had propagated and the concrete separation was more pronounced, S&L was again requested to inspect the crackin S&L reiterated their earlier recommendatio At the time of the inspection, no deviation report or nonconformance report had been initiate The inspector considered the lack of tracking of this issue in a formal corrective action system to be a weaknes Communication Among Corporate Engineering Organizations The onsite engineer with cognizance for this issue reports to the Systems Engineering.Design section within the, corporate engineering organizatio The corporate engineering group with the responsibility for evaluating civil structural issues is the Mechanical/
Structural Design Engineering Sectio The Mechanical/
Structural Design Engineering Section did not review S&L's initial structural evaluation nor were they aware of the problem prior to the NRC informing them of the cracking during this inspectio The inspector considered this to be a weakness in communication.
Engineering and Technical Support This portion of the inspection focused on the effectiveness of the licensee's engineering and technical support organization Engineering support was provided to the site primarily by three groups, the station's Technical Staff, the Nuclear Engineering Division's projects engineering group at the site (Engineering and Construction (ENC)
group), and the rest of the Nuclear Engineering Division's discipline engineering groups located at Downers Grove._ The station's Technical Staff provided system engineering and other technical support at the sit Corporate engineering activities were coordinated through the ENC group, which would either perform the work or forward it to the corporate office where the projects group would interface with the discipline engineering group Engineering was evaluated focusing on the following:
Engineering Backlog and Management Tracking of Workload
Prioritization of Modifications
Engineering Support
Engineering Communications Effectiveness
Training, Qualification, and Certification Engineerin9 Backlog and Management Tracking of Workload The inspectors reviewed the backlog and workload for both site and corporate engineering organization Most action items were completed by their scheduled date The station technical staff appeared to.be strained based on the number of systems and issues being dealt
wit This may have been the result of, or exacerbated by, the lack of experience of several of the systems engineer Station management tracked work items for engineers using the nuclear tracking system (NTS) and a daily listing of regulatory activitie Updating the status and prioritizing the remaining items was generally done during the daily meetings between technical staff management and group leader During the inspection, the licensee focused attention on a reduction of the number of overdue regulatory activity item Prioritization of Modifications The licensee had developed and implemented a numerical point system for prioritizing major modification The system applied different weighting factors to various attributes of the modification, such as whether it would improve public safety, safety system performance, productivity, et The highest factor was assigned to items of safety significanc The overall score then determined the relative priority of each modificatio The inspectors considered the prioritization system to be workable and usefu The licensee did not prioritize minor modifications or other more routine work, stating that these items were often performed on the basis of what was "hot". Engineering Support The inspectors evaluated the interfaces among plant operations and maintenance staff, plant technical staff, onsite engineering, and corporate engineerin Technical staff personnel (TS) indicated that they were kept informed about the status of their system In addition, TS routinely reviewed all work request cover sheets submitted on their systems. If corporate support was needed, they would contact ENC at the site or directly contact various disciplines within NE The interface between operations and TS was generally good, although TS lack of system expertise reduced their effectivenes TS generally responded to operations when called upo The presence of the corporate Engineering and Construction (ENC) group onsite improved the overall quality of modifications and has improved engineering's respons The corporate strategy of establishing a more self-suff icient engineering organization was also a positive ste The licensee recently established a dedicated architect/engineer (A/E) for each sit Because the dedicated A/E for Dresden was not the original A/E, the licensee was in the process of transfering the responsibility to the new A/ Engineering Communication Effectiveness The inspectors examined the communication paths among the segments of the licensee's engineering support organization The normal flow of problems or concerns would be as follows:
identification by plant personnel,
informal communication of problem to TS, followed by a written work request (discussed in Section 6.C above),
informal communication between TS and ENC, followed by either a request form or an AIR,
communication between ENC and corporate engineering to determine whether the problem should be handled onsite or at corporate, and
communication between corporate and the dedicated A/E for items involving a potential modificatio Per procedures, all formal communications from engineering to the site was in the form of a letter to the station manage The inspectors evaluated communications among onsite engineering (ENC), corporate engineering (NED),. and the Technical Staff (TS).
Communications between corporate engineering and the dedicated A/E was not evaluate.
Between Onsite Engineering (ENC) and Technical Staff The communication between these two groups was goo The inspectors found the staff in the two organizations communicated freely on technical issues related to Dresde The daily morning meetings between the technical staff and the onsite engineering personnel enhanced the communication between these two group Another example of good communications was the weekly conference calls between the station's nuclear
- engineers and the nuclear fuel services organizatio Between ENC and Corporate Engineering Communications. ~etween ENC and corporate engineering were not always effective or timel One example is discussed in Section 5.B abov Another example was the lack of awareness by corporate engineering personnel with a training program developed by the Mechanical/Structural staf This program was for the preparation, review, and approval of calculation Another example was that it took one month for the issues discussed in AIR 91-07 to get to the appropriate discipline group from the project engineering grou The inspectors concluded that communication flow between ENC and corporate engineering still needed improvemen In contrast, the communication between the onsite and corporate sections of the same group within NED was acceptabl This communic.ation normally flowed through the onsite Engineering Group superviso.
Between Corporate Engineering and Technical Staff The inspectors evaluated the programs established by the licensee to identify generic engineering issues and found that there was still a need for improvemen Although a good mechanism had evolved to collate and evaluate the information; personnel were not always familiar with either the system or the informatio Training and Qualification Effectiveness The inspectors evaluated the experience and training of tech staff and engineering personnel and determined that in many cases, the system engineers did not have detailed, indepth knowledge of their system In contrast, corporate engineering personnel were experienced, as many of the.onsite corporate engineers had been site Technical Staff engineer The reasons for the lack of system engineer familiarity with their systems were related to the following.:
Lack of industry or site experience, and
Insufficient training prior to assuming role as a systems engineer 13 Lack of Industry or Site Experience The inspectors noted that many of the station technical staff were engineers hired directly out of college with about 18 months of experienc While the engineers demonstrated a positive work-ing attitude, their lack of experience and the lack of sufficient training prior to assuming the role of system engineer hampered their effectivenes During a walkdown of a system affected by a modification/ the cognizant engineer for the modification was unable to locate some of the system components without the inspectors'
assistanc Another system engineer did not recognize the significance of a problem until the inspector obtained the design drawings and showed the engineer that the installed system did not meet design requirement An ~dditional case of insufficient experience is discussed in Section 4.B abov Using the system engineering position as a developmental position to some extent is not by itself undesirable; it may, in fact, be beneficia However, where experience levels are generally low and this is not recognized or compensated for by oversight by senior engineers and an agressive training program is not implemented, effectiveness of the systems engineering program is severly hampere We consider this to be the case at Dresde The majority of onsite engineering personnel had more experience than the station technical staf This was primarily because they had been hired from the cadre of experienced station TS personne However, one notable exception is discussed in Section 3.C abov The overall experience for the NED personnel was goo Most had several*years of technical experience in their respective field.
Insufficient Training Prior to Assuming Role as a Systems Engineer Although a comprehensive matrix for tracking and matching qualification versus training had been developed for personnel within corporate
engineering, similar program did not exist for the site technical staff personne Although a "system notebook" concept was in place to provide detailed system information *to system engineers, it did not compensate for the lack of formal training or a qualification progra The lack of a training matrix was discussed with the site Tech Staff training management and the licensee's corporate engineering training managemen.
Review of Quality Assurance Effectiveness The inspectors evaluated the licensee's oversight activities associated with engineerin These were primarily performed by the licensee's corporate Quality Assu*rance/Nuclear Safety (QA/NS) and Engineering Assurance (EA) group Corporate QA/NS performed audits of engineering, both at the site and at the corporate offic The corporate audits tended to focus on current problems, although they also reviewed previous findings to ensure that corrective actions were adequately implemente The EA organization provided a comprehensive technical review of engineering efforts, auditing corporate engineering, onsite engineering, and various A/E' One self-initiated action on the part of these Q organizations was the performance of a "comparative audit."
In this audit, the same team audited the operations area at all six nuclear site They concentrated on good practices, transfering any findings to the site's Nuclear QA grou The comparative audit developed a "model station" to show the stations the ways to improve as a result of this audi A comparative audit of technical support (including the technical staff) was planned for 199 The onsite QA organization followed up on corrective actions to NRC findings, as well as their own, and appeared to provide a good resource to prevent recurrence of previous problem *
In addition to the above two QA organizations, corporate engineering instituted an internal audit process, under the cognizance of E The inspectors determined that EA thoroughly highlighted ongoing problems in the engineering organizatio For example an evaluation of the quality of designer and installer walkdowns identified numerous deficiencie.
Exit Interview The inspectors met with the licensee representatives (denoted in Paragraph 1) on December 20, 199 The inspectors summarized the scope and findings of the inspectio The licensee acknowledged the statements made by the inspectors with respect to the items discussed in this repor The inspec~ors also ~iscussed the likely informational content of the inspection report with regard to documents or processes reviewed by the inspectors during the inspection and the licensee did not identify any such documents or processes as proprietar A telephone conference was held with Mr. L. Gerner of the station to
- discuss the licensee's actions concerning the issues discussed in Section 4 of this report on December 31, 199