ML033430409

Supplemental Information Related to NRC Request for Information Regarding the Adequacy and Availability of Design Basis Information

ML033430409
Person / Time
Site:	Davis Besse
Issue date:	11/20/2003
From:	Myers L FirstEnergy Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
2998
Download: ML033430409 (13)

Text

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Docket Number 50-346 License Number NPF-3 Serial Number 2998 November 20, 2003 United States Nuclear Regulatory Commission Document Control Desk Washington, D. C. 20555-0001

Subject:

Supplemental Information Related to NRC Request for Information Regarding the Adequacy and Availability of Design Basis Information Ladies and Gentlemen:

By letter dated October 9, 1996 (Log Number 4928), the NRC requested information pursuant to 10 CFR 50.54(f) regarding the adequacy and availability of design basis information. By letter dated February 11, 1997 (Serial Number 2438), the Davis-Besse Nuclear Power Station (DBNPS) responded to this request. In its response, the DBNPS stated much of the effort to compile the DBNPS design basis had been completed. This had been accomplished through the establishment of the DBNPS Configuration Management Program and through the development of System Descriptions and the Design Criteria Manual. The DBNPS further stated that it had commenced a Design Basis Validation Program (DBVP) to further assure that design basis information, specifically design basis calculations, was consistently reflected in the physical plant and those controlled documents used to support plant operation. By letter dated March 31, 1997 (Serial Number 2455), the DBNPS provided a plan and schedule for completion of the DBVP. By letter dated December 17, 1999 (Serial Number 2623), the DBNPS provided an update on the DBVP status and schedule.

This letter completes the action the FirstEnergy Nuclear Operating Company (FENOC) staff agreed to take during its meeting on May 7, 2003, with the NRC staff regarding the resolution of design issues. This letter provides supplemental information regarding the activities undertaken by FENOC during the ongoing thirteenth refueling outage to provide additional assurance of the adequacy and availability of design basis information.

In particular, this letter summarizes the status of corrective actions identified by the DBVP, the results of the Return to Service Plan as it pertains to system health, additional actions FENOC is taking to improve design basis information and documentation, and how these actions relate to the DBNPS's original response dated February 11, 1997 (Serial Number 2438).

Docket Number 50-346 License Number NPF-3 Serial Number 2998 Page 2 Status of Design Basis Validation Program Qpen Items The DBNPS's response to the NRC's request for information regarding the availability and adequacy of design basis information dated February 11, 1997, concluded that there were weaknesses in design calculations (such as missing calculations and calculations that did not always provide sufficient detail to verify assumptions and conclusions).

Based upon the identified weaknesses in calculations, the DBNPS initiated the DBVP to provide further assurance that design basis calculations were consistently reflected in the physical plant and controlled documents, and contained sufficient information to support the underlying assumptions in the calculations.

At the beginning of 2002, it was determined that the DBNPS had been slow to implement action for certain issues identified in the DBVP. Specifically, the DBNPS staff determined that a number of issues had not received action and were the subject of open requests for assistance for resolution from Engineering. The DBNPS staff subsequently determined that these issues either had been corrected, or it documented the issues on Condition Reports (CRs) and entered them into the DBNPS Corrective Action Program.

Additionally, the DBNPS staff identified some cases in which the prior corrective action for DBVP issues was not adequate. These issues also have been documented on CRs and entered into the DBNPS Corrective Action Program (CAP).

In accordance with FENOC's normal processes, the CRs were evaluated for potential impact on the operability of the plant's systems, structures and components (SSCs). The CRs were also reviewed to ensure that the proper significance classification and evaluation method was applied to the CR. Additionally, in accordance with DBNPS's Restart Action Plan, the CRs were reviewed by the Restart Station Review Board (RSRB), to determine whether they presented a potential restraint to restart. As provided in the Restart Action Plan, a condition was designated as a restart action item if it satisfied one or more of seven criteria, including: affecting operability, representing a nonconformance with the design basis, or representing a nonconformance with the license or a license condition. Those identified conditions that are classified as restart restraints require evaluation for needed corrective actions prior to restart from the current outage. Those identified conditions that are not classified as restart restraints are being prioritized and scheduled for resolution within the CAP, which may occur after restart of the plant. This process provides assurance that appropriate corrective actions will be taken prior to restart for those conditions identified by the DBVP that could affect safety.

The number of DBVP open items has been reduced to approximately 100. Among the remaining open items, only a small number are designated as restart items. The remaining non-restart items are not safety-significant, do not affect safety functions, and are relatively minor. Examples include such items as voiding or revising the status of calculations to indicate the calculation is no longer current and updating calculations to reflect minor revisions that do not affect the calculations' conclusions. These remaining

Docket Number 50-346 License Number NPF-3 Serial Number 2998 Page 3 open items have been documented in CRs and entered into the DBNPS's formal CAP.

They will be addressed in a timely manner consistent with their safety significance.

System Health Assurance Plan In response to the discovery of Reactor Pressure Vessel Head degradation during March of 2002, FENOC developed a Return to Service Plan to establish a course of action for safe and reliable return to service. The Return to Service Plan consisted of seven "building blocks." One of these "building blocks," the System Health Assurance Plan, included verification of aspects of the DBNPS design basis. A summary of the design basis verification activities performed under the System Health Assurance Plan and their results are contained in Attachment 1.

The System Health Assurance Reviews, which included the Latent Issues Reviews and the Safety Function Validation Project, examined the safety functions of [s systems whose functions comprise 99 percent of core damage frequency (CDF) and large early release frequency (LERF). As a result of these reviews, FENOC concluded that, in general, the systems could perform their safety functions. However, FENOC identified a generic concern with respect to the lack of a robust calculation control process. In addition, in a few cases, FENOC determined that some conditions adversely affected the safety functions of several systems. In those cases, FENOC has taken or will take corrective action prior to restart to restore the functionality of the systems, and has performed reviews to bound the extent of condition. As a result, FENOC concludes that there is reasonable assurance that plant systems can perform their design basis safety functions and are ready to support safe restart and operation of the DBNPS, subject to completion of the remaining restart actions. Additionally, as discussed below, FENOC is taking action to improve its calculations.

Design Basis Information Documentation and Control Improvements As noted in the DBNPS original response (Serial Number 2438), the System Descriptions were one of the documents intended to contain DBNPS design bases information. The Latent Issues Reviews Collective Significance and the Assessment of Engineering CR evaluations concluded less than adequate managerial methods and applied rigor had resulted in the deterioration of the capabilities of the engineering organization to support safe and reliable plant operation. This included issues with the System Descriptions. As a result, a System Description Improvement Plan is being developed. This effort is intended to determine where design information is to be located and how it will be controlled. This effort is intended to include revising the System Descriptions. The System Description improvements from this plan will be completed by December 31, 2004. Intended actions to strengthen the DBNPS engineering organization capabilities are described in Revision I of the Root Cause Analysis Report - Assessment of Engineering Capabilities, which was submitted to the NRC by letter dated May 2, 2003 (Serial Number 1-1314), and in the Management and Human Performance Root Cause

Docket Number 50-346 License Number NPF-3 Serial Number 2998 Page 4 Analysis Report on Failure to Identify Reactor Pressure Vessel Head Degradation, which was submitted to the NRC by letter dated August 21, 2002 (Serial Number 1-1286).

Example actions include: filling key engineering management positions; establishing an engineering assessment board to raise the quality standards of engineering products; and implementing a standard for accessibility of engineering documents. These reports were discussed in NRC Inspection Report 50-346/2002018, dated July 24, 2003.

FENOC has initiated additional actions during the ongoing outage to enhance the quality of design basis documentation. For example, an electronic database to facilitate more efficient access to design basis information will be created and populated with data from the five Latent Issues Reviews systems by September 30, 2004. The database is to include the functions and requirements of structures, systems, and components (SSCs) as well as other design reference information.

Activities to improve the quality of design basis calculations have also been planned as part of the Operational Improvement Plan currently in preparation. The following activities will be performed:

• The procedure governing creation and revision of calculations will be revised to incorporate improvements identified by a recent independent assessment of the DBNPS calculations. The revised procedure will require upgrading existing "critical calculations" (e.g., those which provide Technical Specification limits and those which support accident analyses in the Updated Safety Analysis Report) to the standards in the new procedure when each is revised during planned modification activities or other planned calculation revisions. The revised procedure will also specify that under emergent circumstances, critical calculations should be upgraded to the standards in the new procedure when each is revised. The procedure governing creation and revision of calculations will be revised by March 31, 2004.

• Following the identification and review of the "critical calculations," a supplemental letter will be provided with a schedule for updating those "critical calculations" identified as requiring revision to the upgraded standards in the revised procedure.

This supplemental letter will be provided by July 30, 2004.

• Training will be provided to the DBNPS engineering staff on the new calculation procedure. This training will include the use of case studies with the objective of achieving better calculation quality. This training will be completed by September 30, 2004.

• A design engineering calculation database will be created. This database will be designed to help manage and keep track of design engineering calculations. This database is to include critical information for the DBNPS calculations including such attributes as the title, purpose, affected equipment, related calculations, and electronic copy of each calculation. Entry of calculation information into the database will occur incrementally with "critical calculations" being incorporated by December 31, 2004.

• An indicator will be developed for monitoring calculation health. This indicator will be implemented by February 27, 2004.

Docket Number 50-346 License Number NPF-3 Serial Number 2998 Page 5 Conclusion In conclusion, certain DBVP open items, including calculation and System Description maintenance, did not receive proper DBNPS engineering management attention.

However, during the current extended outage, FENOC has placed these open items into the DBNPS Corrective Action Program and assessed them to determine whether they were required to be completed prior to restart. In addition, the Latent Issues Reviews, the System Health Readiness Reviews, and the Safety Function Validation Project, including associated corrective actions, provide additional assurance that systems are capable of performing their safety functions. Issues identified by these reviews have been placed into the Corrective Action Program for resolution, and those issues affecting functionality have been or are being corrected prior to restart. Resolution of these issues will provide further assurance of the adequacy and availability of DBNPS design basis information.

Should you have any questions or require additional information, please contact Mr.

Kevin L. Ostrowski, Manager - Regulatory Affairs, at (419) 321-8450.

The statements contained in this submittal, including its attachments, are true and correct to the best of my knowledge, information and belief. I declare under penalty of perjury that the foregoing is true and correct.

Executed on: ___20103 Lev W. Myers, Chie rating Officer MAR Attachments cc: Regional Administrator, NRC Region nI J. B. Hopkins, DB-1 NRC/NRR Senior Project Manager C. S. Thomas, DB-1 NRC Senior Resident Inspector Utility Radiological Safety Board

Docket Number 50-346 License Number NPF-3 Serial Number 2998 Attachment I Page I Summary of Results of System Health Assurance Plan The purpose of the System Health Assurance Plan was to perform reviews of system health prior to restart to ensure that the condition of the plant is sufficient to support safe and reliable operation.

Initial Scone of the System Health Assurance Plan The initial scope of the System Health Assurance Plan included the following levels of system reviews:

Operational Readiness Reviews The Operational Readiness Review was performed to identify whether systems have significant shortcomings, and to initiate immediate actions to correct those problems. Systems for review were selected considering system performance relative to the Maintenance Rule performance criteria, material condition, and operator burdens.

System Health Readiness Reviews System Health Readiness Reviews were performed on risk-significant Maintenance Rule systems not covered by the more extensive Latent Issue Review process. These reviews were more in-depth than the Operational Readiness Reviews and were focused to provide reasonable assurance that these systems can perform their risk-significant maintenance rule functions. These reviews included identification of each system's risk-significant functions, reviews of testing or review of other information (such as trending data) that assesses the system's ability to support risk-significant functions, walkdowns, and reviews of selected data sources. Problems identified during the reviews were captured in the condition report (CR) process. The Restart Station Review Board (RSRB) reviewed the CRs to determine if there were restart requirements.

Latent Issues Reviews Latent Issues Reviews of the reactor coolant system (RCS), auxiliary feedwater, emergency diesel generators, service water, and component cooling water systems were performed. The primary focus of these reviews was to provide reasonable assurance that these systems are capable of performing their safety and accident mitigating functions. These reviews included verification of the design basis functions of the systems and were comprised of an assessment of system attributes, review of various data sources, and walkdowns.

Numerous discrepancies were identified by the System Health Readiness Reviews and the Latent Issues Reviews. Discrepancies were also identified during additional self assessments performed by FENOC and during the NRC-performed Safety System Design and Performance Capability inspection. These discrepancies included hardware-related conditions, inconsistent or potentially

Docket Number 50-346 License Number NPF-3 Serial Number 2998 Attachment I Page 2 non-conservative assumptions in design and licensing basis documents, missing or unavailable calculations, operating and test procedures not reflecting the design documents, and documentation problems. These were documented on CRs in accordance with the Davis-Besse Corrective Action Program (CAP).

The CRs were evaluated for collective significance and the results of the evaluation were documented in the Discovery Phase Collective Significance Report. An evaluation of the potential safety consequences associated with the conditions identified during the reviews was also performed to determine if there could have been significant consequences had an accident occurred.

This evaluation identified a number of conditions with potential safety significance. Based upon these evaluations, FENOC determined that the potentially safety-significant issues pertained largely to calculations. Based upon these results, FENOC decided to expand the initial scope of System Health Assurance Reviews.

Expanded Scope of System Health Assurance Reviews As shown on Figure 1, FENOC's approach for resolving the design-related conditions identified from the initial scope of the System Health Assurance Reviews consisted of three paths.

Path A - Resolution of Each Condition Identified and Determination of the Extent of Condition Each CR was evaluated for the potential effect on the operability of the plant's structures, systems, and components (SSCs). Those identified conditions that did not affect operability and were not classified as a potential restart restraint were prioritized and scheduled for resolution after restart of the plant. As shown in Figure 1, for conditions affecting operability, corrective actions were completed or will be taken. Additionally, an evaluation was performed to determine whether the extent of condition (EOC) was bounded by the scope of another activity being implemented by FENOC, such as the Safety Function Validation Project (SFVP) under Path B, the Design Basis Validation Program (DBVP) performed in the late 1990s, or the actions to resolve the potential programmatic issues under Path C. If not, an EOC review was performed. If the EOC reviews identified other conditions that affected operability, then those conditions were also addressed.

Path B - Evaluations to Provide Additional Assurance of Significant Safety Functions Capabilities As a result of the calculation issues identified during the Latent Issues Reviews, FENOC performed further reviews of calculations to provide additional assurance that Davis-Besse systems are capable of performing their safety functions. These reviews consisted of an evaluation of the calculations for those systems with safety-related functions that contribute significantly to risk. This approach consisted of confirming that design basis calculations demonstrate safety function capability or that applicable tests are performed which demonstrate safety function capability. This review was performed by the SFVP. The scope of the SFVP included those systems with safety related functions that contribute greater than one percent of the total baseline CDF as determined by the Davis-Besse probabilistic safety assessment (PSA). These systems include the systems that were the subject of the Latent Issues Reviews plus 10 other systems: 125/250-volt DC, 480-volt AC,

Docket Number 50-346 License Number NPF-3 Serial Number 2998 Attachment I Page 3 4160-volt AC, high pressure injection (HPI), decay heat/low pressure injection (DHfLP1), HVAC for emergency core cooling system (ECCS) equipment, main steam (MS), safety features actuation system(SFAS), steam and feedwater line rupture control system (SFRCS), and the steam generators (SG). The systems selected on this basis also provide assurance of the adequacy of the plant safety functions that provide a combined 99 percent contribution to large early release frequency (LERF).

Additionally, the containment analyses were reviewed under the auspices of the FENOC Quality Assessment organization. As a result, the containment response analysis was updated. Non-conformances which had not been previously identified were documented on CRs.

Path C - Resolution of Design-Related Programmatic Issues The collective significance of the conditions identified by the system reviews was evaluated to determine if any potential issues were identified in more than one system and, therefore, might reflect the need for process, programmatic, or product improvements. FENOC sorted each condition that was identified during the System Health Assurance reviews into common topical bins. An evaluation was then performed on the set of identified potential issues in each of those bins to determine their potential for collective significance. The evaluation considered several factors, such as the number of identified potential issues in each bin, the ratio of the number of identified potential issues to the number of times the topic attribute was checked by the Latent Issue Review, and whether a potential issue was identified by more than one system review.

The evaluation identified approximately 20 topical areas where the potential collective significance warranted further evaluation. Many of the identified questions and potential issues related to calculations; others related to programmatic areas such as high energy line break (HELB),

environmental qualification (EQ), seismic, Appendix R - safe shutdown, and flooding that were not within the scope of the DBVP; and other potential issues that pertained to various other topics. The potential programmatic issues involving HELB, EQ, seismic, Appendix R - safe shutdown, and flooding were not within the scope of the DBVP. As a result, FENOC took action to address these potential programmatic issues, including determining their extent of condition, as appropriate.

Additionally, FENOC had previously initiated a review of the Air Operated Valve (AOV) program.

Finally, the Discovery Phase Collective Significance Report identified potential weaknesses in other topical areas beyond the calculation and programmatic issues discussed above. These areas did not directly impact the operability of plant structures, systems, and components (SSCs) and therefore, did not require resolution prior to restart.

Results The SFVP system reviews determined that four (HPI, MS, SFAS, SG) of the 10 systems could perform their safety functions, three (DH/LPI, HVAC-ECCS, SFRCS) had safety functions that could not be validated, and the three electrical systems (125/250V, 480V, 4160V) were'determined to be indeterminate based on available information.

In accordance with Path A of its plan for resolution of design issues, FENOC conducted more detailed evaluations of the issues identified by the System Health Assurance Reviews (including the

Docket Number 50-346 License Number NPF-3 Serial Number 2998 Attachment 1 Page 4 Latent Issues Reviews, Safety Function Validation Project, and Topical Area Reviews) to determine their impact on operability. Based upon its evaluations, FENOC determined that the 15 systems that were reviewed in detail (comprising 99% of the CDF and LERF) could perform their safety functions, with several exceptions. For example:

• RPV Head (Licensee Event Report (LER) 2002-02) -FENOC identified through-wall cracking of the CRDM penetrations and corrosion of the RPV head. As a result, FENOC replaced the head, conducted EOC walkdowns inside and outside of the containment to identify whether other components might be similarly affected, and took or will take corrective actions for such components.

• Tornado Missile Protection (LER 2002-006) - FENOC determined that some of the EDG exhaust piping was not protected against tornado missiles. Additionally, FENOC identified an exterior door for the Main Steam Line Room that was not adequately protected against tornado missiles. The Davis-Besse plant site was walked down to identify other unprotected SSCs associated with the systems necessary to function in the event of a tornado. A revised evaluation methodology has shown these conditions to be acceptable.

• Air Operated Valves (LER 2003-001) - FENOC implemented an AOV Reliability Program to verify AOV actuator sizing and setpoints. As a result of this program, FENOC identified some AOVs that could not perform their safety function.

Corrective action has been or will be taken for these valves, including modifications to install new valve actuators and new accumulators as necessary to restore operability.

• High Pressure Injection (HPI) Pumps (LER 2003-002) - FENOC determined that the HPI pumps could be adversely affected by debris in the containment emergency sump water during operation of the pumps in the recirculation mode.

FENOC is modifying the pumps and qualifying the modifications to operate with the debris. Additionally, FENOC evaluated other pumps (e.g., low pressure injection pumps, containment spray pumps) that might be adversely affected by the same condition, and determined that they could adequately perform their safety functions.

• Minimum HPI Recirculation Flow (LER 2003-003) - During its inspections in parallel with the System Health Assurance Reviews, the NRC identified the minimum flow protection for the HPI pumps might not be sufficient to protect the pumps against damage during certain small break loss of coolant accidents.

Additional minimum flow recirculation lines have been installed to correct this condition.

• Electrical Distribution System (EDS) (LER 2003-007) - FENOC determined that its electrical system distribution calculations were not sufficient to verify the function of the EDS. Many of the unvalidated functions in the 480V and 4160V systems were related to known deficiencies in the Electrical Load Management System (ELMS) calculation. To address these and other deficiencies, FENOC replaced the ELMS calculation with a new Electrical Transient Analysis Program (ETAP) - based calculation. Based upon the results of the ETAP calculations,

Docket Number 50-346 License Number NPF-3 Serial Number 2998 Attachment 1 Page 5 FENOC detennined the EDS could not perform its function under conditions involving the simultaneous occurrence of low grid voltage and a loss of coolant accident. As a result, FENOC is making modifications and establishing administrative limits to ensure that sufficient voltage will be available for essential components.

Additionally, during the early stages of the current outage, FENOC discovered that the decay heat removal (DHR) system may not be able to maintain long-term recirculation flow because the suction screen for the containment emergency sump could become clogged by debris and because gaps in the screens could allow debris to pass through to the pump. This debris could be generated by steam blowdown during a loss-of-coolant accident (LOCA) or by containment washdown during containment spray mode. This condition was reported in LER 2002-005. In response to the identification of the issue regarding the containment emergency sump, FENOC took several actions as part of the Containment Health Assurance Plan, including removing materials from containment that could be the source of such debris (e.g., unqualified coatings) and revising the design of the emergency sump screen. This revised design involved removal of the existing screen and installing a strainer assembly with much greater surface area. This modification expanded the screen surface area from the previous 50 square feet to approximately 1200 square feet of available area while decreasing the individual opening size and shape from approximately 1/4 inch square openings (5/16 inches diagonal) to 3/16 inch circular openings. Activities to address debris sources in containment and the containment emergency sump are discussed in the Davis-Besse response to NRC Bulletin 2003-01, dated August 8, 2003 (Serial Number 2977).

Conclusions The System Health Assurance Reviews examined the safety functions of 15 systems whose functions comprise 99 percent of CDF and LERF. As a result of these reviews, FENOC concluded that, in general, the systems could perform their safety functions. In a few cases, FENOC determined that some conditions adversely affected the safety functions of several systems. In those cases, FENOC has taken or will take corrective action to restore the functionality of the systems prior to restart, and has performed reviews to bound the extent of condition. As a result, FENOC concludes that subject to completion of the remaining restart actions, there is reasonable assurance that plant systems can perform their design basis safety functions and are ready to support safe restart and operation of Davis-Besse.

Docket Number 50-346 License Number NPF-3 Serial Number 2998 Attachment I Page 6 FIGURE I -- RESOLUTION OF ISSUES Path A Path C Not Operable or Requires Further Evaluation Condition Not Valid Path A

Docket Number 50-346 License Number NPF-3 Serial Number 2998 Page 1 COMMITMENT LIST The following list identifies those actions committed to by the Davis-Besse Nuclear Power Station (DBNPS) in this document. Any other actions discussed in the submittal represent intended or planned actions by the DBNPS. They are described only for information and are not regulatory commitments. Please notify the Manager -

Regulatory Affairs (419-321-8450) at the DBNPS of any questions regarding this document or any associated regulatory commitments.

COMMITMENT DUE DATE

1. The System Description improvements from 1. December 31, 2004.

this [System Description Improvement] plan will be completed.

2. An electronic database to facilitate more 2. September 30, 2004 efficient access to design basis information will be created and populated with data from the five Latent Issues Reviews systems. The database is to include the functions and requirements of structures, systems, and components (SSCs) as well as other design reference information.

3. The procedure governing creation and revision 3. March 31, 2004 of calculations will be revised to incorporate improvements identified by a recent independent assessment of the DBNPS calculations. The revised procedure will require upgrading existing "critical calculations" (e.g., those which provide Technical Specification limits and those which support accident analyses in the Updated Safety Analysis Report) to the standards in the new procedure when each is revised during planned modification activities or other planned calculation revisions. The revised procedure will also specify that under emergent circumstances, critical calculations should be upgraded to the standards in the new procedure when each is revised.

Docket Number 50-346 License Number NPF-3 Serial Number 2998 Page 2 COMMITMENT LIST (Continued)

COMMITMENT DUE DATE

4. Following the identification and review of the 4. July 30, 2004 "critical calculations," a supplemental letter will be provided with a schedule for updating those "critical calculations" identified as requiring revision to the upgraded standards in the revised procedure.

5. Training will be provided to the DBNPS 5. September 30, 2004 engineering staff on the new calculation procedure. This training will include the use of case studies with the objective of achieving better calculation quality.

6. A design engineering calculation database will 6. Entry of calculation information be created. This database will be designed to into the database will occur help manage and keep track of design incrementally with "critical engineering calculations. This database is to calculations" being incorporated include critical information for the DBNPS by December 31, 2004.

calculations including such attributes as the title, purpose, affected equipment, related calculations, and electronic copy of each calculation.

7. An indicator will be developed for monitoring 7. February 27, 2004 calculation health. This indicator will be implemented.