IR 05000269/2012013
| ML12366A264 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 12/31/2012 |
| From: | Nease R L NRC/RGN-II/DRS/EB1 |
| To: | Gillespie T P Duke Energy Corp |
| Linda K. Gruhler 404-997-4633 | |
| References | |
| IR-12-013 | |
| Download: ML12366A264 (21) | |
Text
December 31, 2012
Mr. T. Preston Gillespie, Jr.
Site Vice President Duke Energy Corporation Oconee Nuclear Station 7800 Rochester Highway Seneca, SC 29672-0752
SUBJECT: OCONEE NUCLEAR STATION UNIT 3 - REACTOR PROTECTIVE SYSTEM/ENGINEERED SAFEGUARDS PROTECTIVE SYSTEM (RPS/ESPS) DIGITAL MODIFICATION - U.S. NUCLEAR REGULATORY COMMISSION INSPECTION REPORT 05000287/2012013
Dear Mr. Gillespie,
Jr.:
On October 9, 2012, the U. S. Nuclear Regulatory Commission (NRC) completed an inspection at your Oconee Nuclear Station, Unit 3 reactor facility. The enclosed inspection report documents the inspection results, that were discussed with you and other members of your staff.
The inspection was performed in accordance with Inspection Procedure 52003, "Digital Instrumentation and Control Modification Inspection," and also focused on the list of recommended "Site Inspection Follow-Up Items" outlined in the RPS/ESPS Safety Evaluation dated January 28, 2010, (ADAMS Accession Number ML100220016). The inspection examined activities conducted under your license as they relate to safety, compliance with the Commission's rules and regulations, and with the conditions of your license. The team reviewed selected procedures and records, observed activities, and interviewed personnel. No findings were identified during this inspection. In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter, its Enclosures, and your response (if any) will be available electronically for public inspection in the NRC Public Document Room, or from the Publicly Available Records (PARS) component of the T. P. Gillespie, Jr. 2 NRC's Agencywide Documents Access and Management System (ADAMS). ADAMS is accessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room).
Sincerely,/RA by Eric J. Stamm Acting For/ Rebecca L. Nease, Chief Engineering Branch 1 Division of Reactor Safety Docket No. 50-287 License No. DPR-55
Enclosure:
Inspection Report 05000287/2012013,
w/Attachment:
Supplemental Information cc: (See page 3 and 4)
SUMMARY OF FINDINGS
IR 05000287/2012013; 5/7/2012 - 10/9/2012; Oconee Nuclear Station, Unit 3; Digital Instrumentation and Control Modification Inspection.
This inspection was conducted by a team of three NRC inspectors from the Region II office, and one technical reviewer from the Office of Nuclear Reactor Regulation. No findings were identified. The NRC's program for overseeing the safe operation of commercial nuclear power reactors is described in NUREG-1649, "Reactor Oversight Process," (ROP) Revision 4, dated December 2006.
REPORT DETAILS
Background Information On January 31, 2008, Duke Energy Carolinas submitted a first-of-a-kind license amendment request to upgrade the Oconee Nuclear Station to a digital Reactor Protective System (RPS)and Engineered Safeguards Protective System (ESPS). The proposed amendment would allow replacement of the existing Bailey Meter Company analog, solid-state design, RPS/ESPS with a digital computer based TELEPERM XS (TXS) platform at Oconee Units 1, 2 and 3. The digital RPS/ESPS would provide signal processing, signal validation, and protection logic function for these systems.
NRR approved the LAR and issued a safety evaluation report (SER) dated January 28, 2010 (ML100220016). NRR conducted an evaluation of the license amendment as part of the normal review process. This included a review of the design and capabilities of the modification. Regional inspectors were tasked with performing documentation and functionality reviews after the system left the vendor in accordance with Inspection Procedure 52003.
In addition, the SER discussed inspection activities (Section 3.14., Regional Activities) for the digital RPS/ESPS that would be addressed by the NRC regional office during site acceptance testing, installation, startup testing, and operation of the system. The activities, referred to as inspection follow-up items, were intended to verify licensee activities that were not part of the licensing process, but were related to the safe operation of the digital RPS/ESPS system. The bases for the inspection activities were derived from Chapter 7 of the Standard Review Plan (SRP), and explained in detail throughout the SER.
Region II developed a site-specific inspection plan to select and review the activities associated with the major phases of the digital I&C modification. Region II observed portions of testing, installation, and operation of the RPS/ESPS modification on Unit 1 in 2011. This included a sample of inspection requirements involving four major areas of effort: (1) developing an understanding of the modification design; (2) documentation verification; (3) review of testing, operations, and training; and (4) a review of plans for maintenance and repair efforts. The results of the inspection were documented in Inspection Report 05000269/2011011 (ML 12069A088).
This report documents the inspection results for the RPS/ESPS modification on Unit 3. For the Unit 3 review, the site-specific inspection plan included an emphasis on: 1) review of corrective action program (CAP) documents to ensure lessons learned and operating experience had been properly captured and implemented; and 2) additional emphasis was considered for those licensee activities that included new or different management controls, or were being managed/controlled in a different manner, or implemented with new techniques. Because the SER was applicable to all three units, many of the inspection follow-up items that were previously reviewed during the Unit 1 inspection effort were not reviewed again.
OTHER ACTIVITIES
4OA5 Other Activities - Digital Instrumentation and Control Modification Inspection
.1 Design Review
.1.1 Full Scope Modification
a. Inspection Scope
The team reviewed all the documentation required to gain a working knowledge of the digital instrumentation and control (I&C) modification including, but not limited to: the staff's SER; any licensing commitment documents; manufacturer's literature on the hardware and software being installed; and applicable drawings and schematics. In addition, the team reviewed design specification attributes including design architecture, input consolidations, isolation and interface devices, affected indicators, and the credited function of the system to verify proper system requirements were met and/or maintained during installation.
The team discussed several changes the licensee made during the Unit 1 installation to verify that they were appropriately captured in the Unit 3 scope. The team also reviewed the Unit 3 modification project plan to determine if any changes following installation on Unit 1 had been appropriately evaluated.
b. Observations and Findings
No findings were identified. The team determined that given the complexity and large scale of the modification, the licensee adequately implemented the full scale design.
The team reviewed Problem Investigation Program (PIP) O-11-8106 documenting the licensee's lessons learned from Unit 1, and observed that the Integrated Test performed on Unit 1 was not being performed on Unit 3, or following installation on Unit 2 in 2014.
The PIP stated that the Unit 3 modification test plan should outline the purpose for the integrated test performed on Unit 1, and the necessary justification to support not performing the test on Unit 3. When the team reviewed the Unit 3 mod test plan, it was noted there had been no justification for not performing the test. The team questioned whether there were components or features that would not be tested due to removal of the integrated testing. Following discussions, the licensee revised the modification test plan to document that the integrated test performed on Unit 1 was to be a final demonstration of what was considered to be the worst cases for the network loading and power supply loading with all ES channels tripped and six of 10 RPS trips generated. This test scope was not required by the SER, or by the post-modification testing requirements. Software integration and loading of the TXS cabinet power supplies was demonstrated by Factory Acceptance Testing, Site Acceptance Testing, and post-modification verification and functional tests. The team found the justification acceptable.
.1.2 Modification Schedule
a. Inspection Scope
The team reviewed the licensee's proposed schedule for implementation to verify the licensee properly evaluated any associated shutdown risk due to modification implementation and emergent changes to the schedule. The team reviewed the licensee's modification plan to verify whether the implementation would be done in conjunction with shutdown risk activities, such as a complete core offload or mid-loop operations. The team reviewed and assessed the emergent issues to evaluate the potential impact on the overall implementation and testing schedule.
b. Observations and Findings
No findings were identified. The team determined the licensee adequately scheduled installation, maintenance, and testing appropriate to the circumstances. As emergent issues arose, the licensee would prioritize issues utilizing safety and risk insights. The team determined the licensee incorporated lessons learned from the Unit 1 installation which provided for more effective scheduling.
.2 Documentation Review
.2.2 Procedure Review
a. Inspection Scope
The team performed, on a sampling basis, a review of the licensee procedures affected by the modification of the RPS/ESPS system. PIPs were reviewed to verify issues that arose during installation that may affect procedural guidance were appropriately entered into the CAP and resolved.
The inspection consisted of the review of surveillance, abnormal operating, emergency operating, annunciator response, maintenance, and testing procedures that were updated for Unit 3. These procedures were reviewed in order to assure that they accurately reflected Unit 1 implementation; any new systems attributes; and were in accordance with the design commitments and technical specifications. The team was provided a list of changes made to Unit 3 RPS/ESPS versus Unit 1 installation, which included the approved scope of the Unit 3 engineering changes and the associated PIPs. There were several PIPs reviewed from this list to confirm adequate changes were made to the Unit 3 and associated procedures. The team also reviewed the engineering change (EC) documents for the RPS and ESPS project (EC 77069 and EC 77070).
b. Observations and Findings
No findings were identified.
Procedures:
The team determined that the RPS/ESPS Maintenance, Testing, and Operation procedures reviewed for Unit 3 were adequate and consistent with Unit 1, the design capability, and plant specifications. Any modifications that were made on Unit 3 and differed from Unit 1 were reflected in the Unit 3 procedures.
The team requested several operational procedures from the licensee in order to verify that the test machine, which is a portable unit that can be used to perform calibration checks and logic tests on TXS systems, was correctly identified in the procedures. The licensee staff stated that the test machine was not incorporated in their operation procedures because they have no plan to use the unit in the future. The team also determined that the implementation of the Technical Specifications (TS), applicable licensee standards, and vendor recommendations were appropriately integrated in the sampled calibration procedures.
The team reviewed several PIPs (listed in the Documents Reviewed section of this report) that were listed on a requested lessons learned list of Unit 1 issues. These PIPs were written as a result of various issues discovered during Unit 1 installation of the RPS/ESPS system, and some required hardware modifications or procedure changes, as resolution. Affected procedures that were listed in the PIP were reviewed by the team to verify described changes were actually implemented in the procedure, and were similar to those changes of Unit 1 procedures.
The team identified some differences in the Unit 3 procedures; however, interviews with the licensee staff revealed that these differences were either new modifications planned for Unit 3, which will be implemented on Unit 1 at a later date; or they were minor changes that would only be specific to Unit 3. The changes that were relevant to the human factors of the Graphical Service Monitors (GSM) were verified by inspectors, because according to the written PIPs, the GSM for Unit 1 required several modifications that have not yet been implemented on Unit 1. According to the licensee, the required changes for Unit 1 have been captured and will be reflected in the continuous use procedures for Unit 3 by use of notes to point users to differences for Unit 3. The work to implement the changes on Unit 1 is scheduled for the next outage date. The inspectors interviewed training personnel to verify that maintenance personnel were trained in the differences between the systems on each unit. According to the licensee, the training did not have to be repeated because the same user skill set required for Unit 1 is used for Unit 3. For other changes implemented, the users are able to refer to procedures, as well as the Users Manual and training was not required.
Configuration Management: On Unit 1, the licensee failed to perform adequate post modification testing to evaluate the adequacy of a design modification to the RPS/ESPS, and allowed an improper wiring configuration of the nuclear instrumentation (NI) Power Range detector cables affecting all four RPS channels (LER 05000269/2011-05-01). The team determined the licensee took appropriate corrective actions to prevent this from happening on the Unit 3 RPS/ESPS modification.
The team conducted interviews and was provided with the corrected drawings and procedures for Unit 3. The design drawings used for the connection of the NI cables were modified to show in more detail the connection points for each cable. Procedure TN/3/A/77070/001, "Reactor Protective System Replacement Modification," was modified to show proper labels for the cable terminations, and new signature blocks for implementation management and engineering oversight were added. A new continuity test sequence for Power Range NIs was added to procedure TN/3/A/77070/001. A new section was also added to procedure TN/3/A/77070/002, "Functional Checkout of Unit 3 RPS Replacement Modification," to include the Power Range NI, and hot leg cable testing.
The team inspected the RPS Channel A cabinet 1 (3PPSCA0001) to verify that the Power Range connection for 3NI-5 was performed according to drawing O-2781, Rev.
16E. The team concluded that the connection of triaxial cables JC and JA was performed according to the drawing.
Bend Radius:
During the Unit 1 installation and inspection, the team noted that the four channels of the RPS system had wires (e.g., Okonite model 3BA-12U) that had appeared to have exceeded the allowable bend radius. The inspectors determined that the training radius for the wire, as specified by the manufacturer, was four times the outer diameter (4xOD) of the wire. The licensee documented this issue in the CAP as PIP O-11-6850. The licensee concluded that guidance for recommended target minimum bending radius for individual insulated conductors within enclosures would be added to the procedures for making cable terminations, as well as included in the pre-job briefings for such work.
Just prior to the inspection team's arrival onsite for the Unit 3 inspection, the licensee discovered the procedures had not been properly updated. As a result, the licensee issued PIP O-12-5512 and conducted a walkdown to determine if there were any wires that exceeded their bend radius. The results of the inspections identified five examples of wires that were bent more than needed; however, the licensee noted none of the examples were reported as being less than the 4xOD limit. A follow-up walkdown was performed by the inspection team. The team inspected ES cabinets 3PPSCA0017, 3PPSCA0018, and 3PPSCA0010; and RPS cabinets 3PPSCA0001 and 3PPSCA0002, for potential bend radius issues on cables and conductors. The team observed several examples of inadequate bend radius (most notable in RPS cabinet 3PPSCA0001) that were less than 4xOD.
The team identified that the licensee did not adequately incorporate acceptance criteria for bend radii of low voltage cables as a result of an NRC issue identified during Unit 1 RPS Installation. Specifically, the NRC identified that the governing procedures for conductor installation (DPS-1390.01-00-003 and IP/0/A/3009/017,"Wire Terminal Installation, Labeling, and Termination 600V or Less," Rev. 35), did not have specific guidance to verify bend radii for single conductor cables that could cause degradation.
The licensee conducted a subsequent follow-up inspection and provided an update to PIP O-12-5512; where they listed the conductors, (approximately 54, excluding spares and shields), that were identified to have a small bend radius, (between 1xOD and 2xOD), and were subsequently corrected (to 4xOD or greater) per work orders. The licensee stated that they had no plans to correct any spare or shield cables that may have inadequate bend radii. The inspectors noted that spare cables should be tested prior to being used to ensure no damage has occurred due to an inadequate bend radius.
Based on the information collected and evaluations performed, the licensee determined the minimum bend radius to be 2xOD for individual conductors 10AWG and smaller, serving low voltage, low current instrumentation and controls circuits. The licensee stated conductors for power feeder cables shall follow vendor recommended bend radius values; and conductors for lw voltage, low current I&C cables should be not less than 2xOD minimum bend radius; unless restricted by vendor qualification reports. Following several discussions and review of the evaluations performed by the licensee, the team found the licensee's position on bend radius acceptable. Because the system had not returned to service at the time of discovery, the as-found cables were not considered degraded, and the licensee took immediate corrective actions, the team considered this issue appropriately resolved.
Panel Wiring:
The inspection team performed spot checks to verify cable terminations on the RPS and ESPS cabinets were being performed according to the drawings. The team inspected the following cabinets, terminals, and drawings:
- For RPS cabinet 3PPSCA0001, the team looked at terminal blocks X011 and X111 and compared them with drawing O-2781, Rev. 16E ('Interconnection Diagram Nuclear Instrumentation and Reactor Protection System Cabinet 3PPSCA0001')
- For RPS cabinet 3PPSCA0002, the team looked at terminal blocks X023, X026, and X122 and compared them with drawing O-2781-02, Rev. C ('Interconnection Diagram Nuclear Instrumentation and Reactor Protection System Cabinet 3PPSCA0002'); and terminal block X016 and compared it to drawing O-2781-03, Rev. D ('Interconnection Diagram Nuclear Instrumentation and Reactor Protection System Cabinet 3PPSCA0002')
- For ESPS cabinet 3PPSCA0017, the team looked at terminals 53 and 56 on terminal block 121 and compared it with drawing O-2757-G, Rev. 18C ('Connection Diagram Engineering Safeguards Cabinet 3PPSCA0017'); and terminal blocks X112, TB-5, and TB-6 and compared them to drawing O-2757-G-001, Rev. D ('Connection Diagram Engineering Safeguards Cabinet 3PPSCA0017') For the terminals checked, the inspectors concluded that the wiring for those terminals was correct. The team conducted interviews and went through the work order that was used to perform the terminations for RPS cabinet 3PPSCA0001. The team noted that compared to the RPS/ESPS cabinets on Unit 1, the cabinets on Unit 3 were wired in a much more organized manner. The licensee attributes this to giving 'ownership' of each cabinet to a group of electricians, and having only them work on those cabinets. The licensee incorporated this format based on lessons learned from Unit 1.
.2.3 Design Bases Document Review
a. Inspection Scope
The team conducted sample reviews of the Updated Final Safety Analysis Report (UFSAR), design basis documents, TSs, and plant drawings to verify that design basis documents were adequately updated to reflect the replacement RPS/ESPS system.
b. Observations and Findings
No findings were identified. The team noted that the design basis documents were adequately updated to reflect the new system and associated design changes. The team also reviewed the UFSAR change summary package and observed the subsequent UFSAR revision included the appropriate updates to reflect the design changes to Unit 3. Because this modification is being installed on each one of the units in phases, the UFSAR revision did not specifically denote which unit was modified; rather it generically addressed units as either a unit with the RPS installed or not installed.
During the Unit 1 installation, the team observed the ES changes and the UFSAR change packages referenced IEEE 279, "Criteria for Protection Systems for Nuclear Power Generating Stations," however, the new RPS/ESPS is licensed to IEEE 603,
"IEEE Standard for Safety Systems for Nuclear Power Generating Stations." The licensee captured this issue in the CAP as PIP-O-11-6663. The team reviewed the status of this PIP and found the licensee took appropriate corrective actions to update the UFSAR.
.3 Testing, Operations, and Training
.3.1 Software Testing Plan
a. Inspection Scope
The team reviewed the installation and startup test procedures for the RPS/ESPS systems to assess whether the procedures ensured that the as-installed modifications were consistent with the SER, the design drawings, and the licensee's commitments. Any changes or deviations from Unit 1 were noted and discussed with the licensee to understand the purpose of any changes and to ensure the design and licensing bases were maintained. The team performed field reviews of the modification of the digital RPS/ESPS system, which was in the process of being installed and tested on Unit 3.
The team observed portions of the installation testing, including component checks, functional testing, and start-up testing to verify the testing plan was adequate in identifying proper design implementation. The team assessed whether the procedures were clear and sufficiently detailed enough to allow site personnel to perform the tests.
The team observed portions of the Unit 3 ES Voter Actuation Testing on the Even Voter.
The licensee used procedure TN/3/A/77069/002, "ES Post-Modification Functional Verification," and inspectors observed Subsection 4.4.13.42 through 4.4.13.66 to verify the testing was adequately performed and the test procedure was properly followed.
The Unit 3 ES Test modification plan (770609) was also reviewed in order to verify that the performed testing procedure used was included in the plan.
The team reviewed several PIPs (listed in the Documents Reviewed section of this report) associated with user document reviews of the RPS/ESPS system given that user documentation evaluations were considered by the NRC staff to be necessary components of acceptable methods for meeting the requirements of Appendices A and B to 10 CFR Part 50 and were not available at the time of the SER.
The team reviewed Duke Energy's Nuclear System Directive 106, Configuration Management, to ensure that software installation and test procedures were developed by the licensee, in accordance with this directive which assures systems, structures, and components are operated, maintained and modified within their design basis. The team reviewed procedure IP/3/A/0315/026, "TXS (Teleperm XS) Service Unit Software Loading," to verify that limitations were put in place to prevent the development of new or modified operational software on the service unit since such actions were not approved in the SER. The inspection team discussed software limitation mechanisms with the licensee to further understand what level of privilege that is required, and who from the staff has such privilege to load the system or application software.
The team reviewed a number of licensee site-specific documents that described the Software Life Cycle process associated with the TXS from the Digital System Specification (ODSS-0806-PPS.0003) document. The Digital System Specification described the recommended requirements as well as the responsibilities to ensure that RPS/ESPS provides intended results. The team assessed the Digital System Specification document to verify that it met the requirements of Branch Technical Position 7-14 (BTP 7-14).
b. Observations and Findings
No findings were identified. The team observed installation testing, functional testing, and system start-up testing. The team found that the test plans assured adequate controls to implement the modification. The team found that the licensee addressed any potential issue according to its safety and risk significance. The team observed the RPS/ESPS system start-up test and that it had functioned properly. It was noted that some inputs could not be simulated during the testing stages, and would only be verified during actual plant startup. These inputs were assessed and determined to be not safety significant, and would cause no increase to public health and safety if not tested prior to startup. The team determined the licensee adequately performed testing which was in accordance with the Unit 3 ES testing procedures and that the testing procedures were detailed and clear.
The team observed that the licensee employed a two-phase process to assess their end user documentation associated with the RPS/ESPS system. First, a document review phase was performed in 2008 in preparation for the Unit 1 project. Then, Verification & Validation (V&V) document evaluation activities in accordance with procedure, Nuclear System Directive 705, were accomplished to demonstrate proper translation of the TXS User Manuals into their end user procedures. The team reviewed PIPs that outlined the different types of issues identified, and the action taken to resolve them, during the document review phase and the V&V document evaluation phase. During the inspection, the team determined that the Software Operations Plan of the Digital System Specification ODSS-806.0003 Attachment F-1, did not clearly define how the licensee would restrict unauthorized changes to the hardware. In addition, the team could not find any provisions on how the licensee would respond to security problems. In accordance with BTP7-14, these measures are to be defined in the license's Software Operations Plan. The inspector could not assess the software Installation Process which describes the installation process, the goals of that process, and a general description of the environment, (such as temperature, humidity, vibration, and rack space), within which the computer system and software system is qualified to operate. The licensee demonstrated that this specific information was captured appropriately in other documents. The licensee captured this issue in the CAP as PIP O-12-6592. 3.4 Personnel Training
a. Inspection Scope
The team reviewed training documents and interviewed personnel to verify that operators, technicians, and system engineers had been adequately trained and have an understanding of the system commensurate with their responsibilities.
b. Observations and Findings
No findings were identified. Following review of relevant documents, the team determined the licensee underwent appropriate training in preparation for implementation of the RPS/ESPS modification. The team reviewed the ongoing training requirements and documents, specifically on Go/NoGo Testing and GSM Functional Testing. The licensee stated training procedures for Unit 1 and Unit 3 were taken from the GSM User Manual. There was no required retraining for Unit 3 maintenance personnel because the User Manual and Operating procedures had been updated with any major differences.
3.5 Hardware and Software Failures
a. Inspection Scope
The team reviewed test incident reports and PIPs to verify the licensee was appropriately capturing hardware and software failures that occurred, and that the issues were properly resolved.
b. Observations and Findings
No findings were identified. The team determined the licensee utilized an appropriate threshold for entering issues into the CAP. The team followed up on several PIPs identified during the Unit 1 installation and found them to have had adequate resolution (the issue with inadequate bend radius was an exception). The team noted that the licensee documented several new issues related to the implementation of the system, categorized each issue based on its significance, proposed appropriate corrective actions, and documented the resolution(s). The issues were appropriately entered into the CAP as PIPs (during the SAT, issues discovered were documented as test incident reports), and subsequently tracked separately in accessible tables. The licensee also reviewed the issues to determine mode applicability to ensure design basis limits and commitments (i.e., TS LCO) were maintained.
3.8 Indication and Annunciation
a. Inspection Scope
The team reviewed procedures, performed walkdowns, and observed control room operations and testing; to verify proper indication and annunciation for system failures, and system bypass were functional, and met the licensing basis as stated in the SER.
b. Observations and Findings
No findings were identified.
4OA6 Meetings, Including Exit Meeting
Exit Meeting Summary The inspection team presented the inspection results to the staff during an exit with members of licensee management on October 9, 2012. The inspectors asked the licensee if any of the material examined during the inspection should be considered proprietary and no proprietary information was identified.
ATTACHMENT: