IR 05000275/2017003
| ML17300B404 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 10/26/2017 |
| From: | Mark Haire NRC/RGN-IV/DRP/RPB-A |
| To: | Halpin E Pacific Gas & Electric Co |
| Mark Haire | |
| References | |
| IR 2017003 | |
| Download: ML17300B404 (37) | |
Text
UNITED STATES ber 26, 2017
SUBJECT:
DIABLO CANYON POWER PLANT - NRC INTEGRATED INSPECTION REPORT 05000275/2017003 and 05000323/2017003
Dear Mr. Halpin:
On September 30, 2017, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at your Diablo Canyon Power Plant Units 1 and 2. On October 5, 2017, the NRC inspectors discussed the results of this inspection with Mr. J. Welsch, Site Vice President and other members of your staff. The results of this inspection are documented in the enclosed report.
NRC inspectors documented one finding of very low safety significance (Green) in this report.
This finding involved a violation of NRC requirements. The NRC is treating this violation as a non-cited violation (NCV) consistent with Section 2.3.2.a of the Enforcement Policy.
If you contest the violation or significance of the NCV, you should provide a response within 30 days of the date of this inspection report, with the basis for your denial, to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, DC 20555-0001; with copies to the Regional Administrator, Region IV; the Director, Office of Enforcement; and the NRC resident inspector at the Diablo Canyon Power Plant.
If you disagree with a cross-cutting aspect assignment in this report, you should provide a response within 30 days of the date of this inspection report, with the basis for your disagreement, to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, DC 20555-0001; with copies to the Regional Administrator, Region IV; and the NRC resident inspector at the Diablo Canyon Power Plant. This letter, its enclosure, and your response (if any) will be made available for public inspection and copying at http://www.nrc.gov/reading-rm/adams.html and at the NRC Public Document Room in accordance with 10 CFR 2.390, Public Inspections, Exemptions, Requests for Withholding.
Sincerely,
/RA/
Mark S. Haire, Branch Chief Project Branch A Division of Reactor Projects Docket Nos. 05000275 and 05000323 License Nos. DPR-80 and DPR-82
Enclosure:
Inspection Report 05000275/2017003 and 05000323/2017003 w/ Attachments:
1. Supplemental Information 2. RFI for O
REGION IV==
Docket: 05000275; 05000323 License: DPR-80; DPR-82 Report: 05000275/2017003; 05000323/2017003 Licensee: Pacific Gas and Electric Company Facility: Diablo Canyon Power Plant, Units 1 and 2 Location: 7 1/2 miles NW of Avila Beach Avila Beach, CA Dates: July 1 through September 30, 2017 Inspectors: C. Newport, Senior Resident Inspector J. Reynoso, Resident Inspector G. Kolcum, Senior Resident Inspector M. Phalen, Senior Health Physicist J. ODonnell, CHP, Health Physicist Approved Mark S. Haire By: Chief, Project Branch A Division of Reactor Projects 1 Enclosure
SUMMARY
IR 05000275/2017003, 05000323/2017003; 07/01/2017 - 09/30/2017; Diablo Canyon Power
Plant; Operability Determinations and Functionality Assessments The inspection activities described in this report were performed between July 1 and September 30, 2017, by the resident inspectors at Diablo Canyon Power Plant and inspectors from the NRCs Region IV office. One finding of very low safety significance (Green) is documented in this report. This finding involved a violation of NRC requirements. The significance of inspection findings is indicated by their color (i.e., Green, greater than Green,
White, Yellow, or Red), determined using Inspection Manual Chapter 0609, Significance Determination Process, dated April 29, 2015. Their cross-cutting aspects are determined using Inspection Manual Chapter 0310, Aspects within the Cross-Cutting Areas, dated December 4, 2014 Violations of NRC requirements are dispositioned in accordance with the NRC Enforcement Policy. The NRCs program for overseeing the safe operation of commercial nuclear power reactors is described in NUREG-1649, Reactor Oversight Process, dated July 2016.
Cornerstone: Mitigating Systems
- Green.
The inspectors identified a non-cited violation of 10 CFR Part 50, Appendix B,
Criterion XVI, Corrective Action, for the failure of the licensee to identify and correct a condition adverse to quality. Specifically, the licensee failed to implement prompt corrective actions related to a nitrogen leak from a component associated with safety-related pressurizer power-operated relief valve (PORV), PCV-455C. The nitrogen leak subsequently resulted in the PORV being declared inoperable, as well as the declaration of an Alert emergency action level classification due the Unit 2 containment atmosphere exceeding habitability limits.
The licensees failure to implement prompt corrective action to correct excessive nitrogen leakage into the Unit 2 containment was a performance deficiency. The finding was more than minor because it was associated with the equipment performance attribute of the mitigating systems cornerstone and adversely affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. Specifically, the excessive nitrogen leakage resulted in the inoperability of safety-related PORV PCV-455C for greater than technical specification allowed outage time and atmospheric conditions in Unit 2 containment that were an immediate danger to life and health, prompting an Alert emergency declaration.
Using NRC Manual Chapter 0609, Significance Determination Process, Attachment 4,
Phase 1 - Initial Screening and Characterization of Findings, and Appendix A, Exhibit 2,
Mitigating Systems Screening Questions, the inspectors determined the finding screened as having very low significance (Green) because: (1) it was not a design deficiency; (2) did not represent a loss of system and/or function; (3) did not represent an actual loss of function of at least a single train for longer than its technical specification allowed outage time; and (4) did not result in the loss of a high safety-significant non-technical specification train. The finding was assigned a human performance cross-cutting aspect associated with consistent processes, in that the licensee did not use a systematic approach in properly assessing the potential risk significance of an increasing trend of nitrogen leakage inside containment [H.13]. (Section 1R15)
PLANT STATUS
Units 1 and 2 began the inspection period at full power.
On July 6, 2017, Unit 1 reduced power to 25 percent to troubleshoot and repair feedwater regulator valve FCV-520 oscillations. Unit 1 returned to full power on July 9, 2017.
Units 1 and 2 operated at or near full power for the remainder of the inspection period.
REPORT DETAILS
REACTOR SAFETY
Cornerstones: Initiating Events, Mitigating Systems, and Barrier Integrity
1R01 Adverse Weather Protection
.1 Readiness for Impending Adverse Weather Conditions
a. Inspection Scope
On September 6, 2017, the inspectors completed an inspection of the stations readiness for impending adverse weather conditions. The inspectors reviewed plant design features, the licensees procedures to respond to high temperatures and grid disturbances due to fires, and the licensees implementation of these procedures. The inspectors evaluated operator staffing and accessibility of controls and indications for those systems required to control the plant.
These activities constituted one sample of readiness for impending adverse weather conditions, as defined in Inspection Procedure 71111.01.
b. Findings
No findings were identified.
.2 Readiness to Cope with External Flooding
a. Inspection Scope
On September 13, 2017, the inspectors completed an inspection of the stations readiness to cope with external flooding. After reviewing the licensees flooding analysis, the inspectors chose one plant area that was susceptible to flooding:
- Unit 1 and Unit 2 intake structure The inspectors reviewed plant design features and licensee procedures for coping with flooding. The inspectors walked down the selected areas to inspect the design features, including the material condition of seals, drains, and flood barriers. The inspectors evaluated whether credited operator actions could be successfully accomplished.
These activities constituted one sample of readiness to cope with external flooding, as defined in Inspection Procedure 71111.01.
b. Findings
No findings were identified.
1R04 Equipment Alignment
Partial Walk-Down
a. Inspection Scope
The inspectors performed partial system walk-downs of the following risk-significant systems:
- July 20, 2017, Unit 2, centrifugal charging pump 2-1
- September 15, 2017, Unit 2, emergency diesel generator 2-1
- September 20, 2017, Unit 2, auxiliary salt water pump 2-2 The inspectors reviewed the licensees procedures and system design information to determine the correct lineup for the systems. They visually verified that critical portions of the systems were correctly aligned for the existing plant configuration.
These activities constituted three partial system walk-down samples as defined in Inspection Procedure 71111.04.
b. Findings
No findings were identified.
1R05 Fire Protection
Quarterly Inspection
a. Inspection Scope
The inspectors evaluated the licensees fire protection program for operational status and material condition. The inspectors focused their inspection on four plant areas important to safety:
- July 11, 2017, Units 1 and 2, intake structure
- July 26-27, 2017, Units 1 and 2, auxiliary saltwater pump rooms 1-1 and 2-2
- August 7, 2017, Units 1 and 2, auxiliary building radiological controlled area located on the 100 foot elevation
- August 23, 2017, Units 1 and 2, H block of auxiliary building 100 foot elevation
- September 19, 2017, Unit 1 and Unit 2, turbine building 85 foot elevation For each area, the inspectors evaluated the fire plan against defined hazards and defense-in-depth features in the licensees fire protection program. The inspectors evaluated control of transient combustibles and ignition sources, fire detection and suppression systems, manual firefighting equipment and capability, passive fire protection features, and compensatory measures for degraded conditions.
These activities constituted five quarterly inspection samples, as defined in Inspection Procedure 71111.05.
b. Findings
No findings were identified.
1R06 Flood Protection Measures
a. Inspection Scope
On September 12, 2017, the inspectors completed an inspection of the stations ability to mitigate flooding due to internal causes. After reviewing the licensees flooding analysis, the inspectors chose the following plant area containing risk-significant structures, systems, and components that were susceptible to flooding:
- Units 1 and 2, diesel fuel oil transfer pump vaults 0-1 and 0-2 The inspectors reviewed plant design features and licensee procedures for coping with internal flooding. The inspectors walked down the selected areas to inspect the design features, including the material condition of seals, drains, and flood barriers. The inspectors evaluated whether operator actions credited for flood mitigation could be successfully accomplished.
These activities constituted completion of one flood protection measures sample, as defined in Inspection Procedure 71111.06.
b. Findings
No findings were identified.
1R11 Licensed Operator Requalification Program and Licensed Operator Performance
.1 Review of Licensed Operator Requalification
a. Inspection Scope
On September 20, 2017, the inspectors observed simulator training for an operating crew. The inspectors assessed the performance of the operators and the evaluators critique of their performance.
These activities constituted completion of one quarterly licensed operator requalification program sample, as defined in Inspection Procedure 71111.11.
b. Findings
No findings were identified.
.2 Review of Licensed Operator Performance
a. Inspection Scope
The inspectors observed the performance of on-shift licensed operators in the plants main control room. At the time of the observations, the plant was in a period of heightened activity. The inspectors observed the operators performance of the following activities:
- August 18, 2017, Unit 1, significant instrument air leak impacting letdown isolation valve CVCS-1-8152, including the pre-job brief
- August 22, 2017, Unit 1, transient from normal letdown to excess letdown In addition, the inspectors assessed the operators adherence to plant procedures, including conduct of operations procedure and other operations department policies.
These activities constituted completion of one quarterly licensed operator performance sample, as defined in Inspection Procedure 71111.11.
b. Findings
No findings were identified.
1R12 Maintenance Effectiveness
Routine Maintenance Effectiveness
a. Inspection Scope
The inspectors reviewed two instances of degraded performance or condition of safety-significant SSCs:
- September 12, 2017, Units 1 and 2, auxiliary salt water
- September 25-28, 2017, Units 1 and 2, 480V switchgear HVAC air balance evaluation The inspectors reviewed the extent of condition of possible common cause SSC failures and evaluated the adequacy of the licensees corrective actions. The inspectors reviewed the licensees work practices to evaluate whether these may have played a role in the degradation of the SSCs. The inspectors assessed the licensees characterization of the degradation in accordance with 10 CFR 50.65 (the Maintenance Rule), and verified that the licensee was appropriately tracking degraded performance and conditions in accordance with the Maintenance Rule.
These activities constituted completion of two maintenance effectiveness samples, as defined in Inspection Procedure 71111.12.
b. Findings
No findings were identified.
1R13 Maintenance Risk Assessments and Emergent Work Control
a. Inspection Scope
The inspectors reviewed four risk assessments performed by the licensee prior to changes in plant configuration and the risk management actions taken by the licensee in response to elevated risk:
- August 1, 2017, Unit 1, vital battery charger 1-1, maintenance outage
- August 22-24, 2017, Unit 2, emergency diesel generator 2-3, extended maintenance outage
- September 13, 2017, Units 1 and 2, auxiliary saltwater, high ocean temperature condition
- September 27, 2017, Unit 2, vital battery charger 2-1, clean and inspection maintenance outage The inspectors verified that these risk assessments were performed in a timely manner and in accordance with the requirements of 10 CFR 50.65 (the Maintenance Rule) and plant procedures. The inspectors reviewed the accuracy and completeness of the licensees risk assessments and verified that the licensee implemented appropriate risk management actions based on the result of the assessments.
The inspectors verified that the licensee appropriately developed and followed a work plan for these activities. The inspectors verified that the licensee took precautions to minimize the impact of the work activities on unaffected SSCs.
These activities constituted completion of four maintenance risk assessments and emergent work control inspection samples, as defined in Inspection Procedure 71111.13.
b. Findings
No findings were identified.
1R15 Operability Determinations and Functionality Assessments
a. Inspection Scope
The inspectors reviewed six operability determinations that the licensee performed for degraded or nonconforming SSCs:
- July 6, 2017, operability determination of Unit 1, steam generator 1-2 level oscillations
- July 26, 2017, operability determination of Unit 2, emergency diesel generator 2-2 turbo air compressor sensing line contamination
- August 4, 2017, operability determination of Unit 2, pressurizer PORV PCV-455C, inoperability due to nitrogen leakage
- August 29, 2017, operability determination of Unit 2, emergency diesel generator 2-3 starting air leak train B pressure control valve PCV-105 leak
- September 12, 2017, operability determination of Unit 1, charging pump lube oil pump not auto stopping
- September 27, 2017, operability determination of Unit 2, auxiliary feedwater pump 1-2 steam supply valve MS-2-FCV-95 leak-by The inspectors reviewed the timeliness and technical adequacy of the licensees evaluations. Where the licensee determined the degraded SSC to be operable, the inspectors verified that the licensees compensatory measures were appropriate to provide reasonable assurance of operability. The inspectors verified that the licensee had considered the effect of other degraded conditions on the operability of the degraded SSC.
These activities constituted completion of six operability and functionality review samples, as defined in Inspection Procedure 71111.15.
b. Findings
Introduction.
The inspectors identified a Green non-cited violation of 10 CFR Part 50, Appendix B, Criterion XVI, Corrective Action, for the failure of the licensee to identify and correct a condition adverse to quality. Specifically, the licensee failed to implement prompt corrective actions related to a nitrogen leak from a component associated with safety-related PORV, PCV-455C. The nitrogen leak subsequently resulted in the PORV being declared inoperable as well as the declaration of an Alert emergency action level classification due the Unit 2 containment atmosphere exceeding habitability limits.
Description.
On June 2, 2016, Unit 2 completed refueling outage 2R19, during which the PORV backup nitrogen system was modified with the addition of larger nitrogen accumulators and new ASME code relief valves. The larger accumulator design improved design margin for accident mitigation of design basis events by increasing the volume of nitrogen available to cycle the PORVs. Extensive leak testing and bench tests verified the new safety-related nitrogen system components were satisfactory, and not leaking, prior to and following the installation. For events in which both the normal instrument air and nitrogen supplies are lost, backup nitrogen accumulators allow the safety-related PORVs (PCV-455C and PCV-456) the ability to be cycled opened and closed a specific number of times over a period of time in response to various design basis scenarios.
On November 22, 2016, evidence of a nitrogen supply system leakage was documented in Notification 50710432. Operators confirmed the source of the nitrogen leakage was inside Unit 2 containment, but the specific location or components were not known.
On December 1, 2016, operators identified a notable change in the nitrogen leak rate.
The Unit 2 nitrogen system supply gas bottles were being changed at a rate far greater than expected compared to Unit 1. The Unit 1 nitrogen bottle change out rate was approximately one bottle per month whereas the Unit 2 nitrogen bottle change out rate had become approximately one bottle every 1-2 days.
On July 28, 2017, operators planned to enter the Unit 2 containment to investigate the nitrogen leakage, first identified in November 2016. Prior to containment entry, two separate air samples were taken and both results showed Unit 2 containment oxygen concentration levels had fallen below the acceptable safe minimum. As a result, operators declared the Unit 2 containment atmosphere was in a condition immediately dangerous to life and health (IDLH). Since the Unit 2 containment is listed as a vital area in the emergency plan and was determined to have an IDLH atmosphere, an Alert emergency classification was declared and the emergency response organization was activated. Immediate corrective actions, as directed by the emergency response team, restored oxygen levels to acceptable levels with initiation of several containment purges.
Subsequent licensee investigations determined the largest nitrogen leak source in the Unit 2 containment (which resulted in the low oxygen environment) was an O-ring failure within the ASME code relief valve RV-355, a safety-related relief valve associated with the PORV PCV-455C backup nitrogen accumulator.
The inspectors reviewed historical data associated with the Unit 2 nitrogen usage and determined that the licensee had identified a leak associated with the nitrogen supply system inside the Unit 2 containment in 2016. Following assessment that the leak was from inside containment, a timely investigation to verify the source of the leak was not completed from December 1, 2016 to July 28, 2017, a period of nearly 8 months. In addition, the inspectors noted a quarterly air sample of Unit 2 containment taken on April 4, 2017, indicated a drop in oxygen concentration level from its normal concentration of 21.3 percent to 19.7 percent, which was an additional missed opportunity for the licensee to have initiated an investigation to identify and resolve this condition, but documentation of the condition was not entered into the corrective action program. Therefore, the inspectors concluded that resolution of the condition was not timely and the potential risk significance was not appropriately evaluated by the corrective action process during troubleshooting. In addition, as a result of the licensees failure to implement prompt corrective actions related to a nitrogen leak, the PORV was rendered inoperable for longer than permitted by TS 3.4.11.
Analysis.
The licensees failure to implement prompt corrective action to correct excessive nitrogen leakage into the Unit 2 containment was a performance deficiency. The finding was more than minor because it was associated with the equipment performance attribute of the mitigating systems cornerstone and adversely affected the cornerstone objective to ensure the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences.
Specifically, the excessive nitrogen leakage resulted in the inoperability of safety-related PORV PCV-455C for greater than technical specification allowed outage time, and atmospheric conditions in Unit 2 containment than were an immediate danger to life and health prompting an Alert emergency declaration.
Using NRC Manual Chapter 0609, Significance Determination Process, Attachment 4, Phase 1 - Initial Screening and Characterization of Findings, and Appendix A, Exhibit 2, Mitigating Systems Screening Questions,. the inspectors determined the finding screened as having very low significance (Green) because:
- (1) it was not a design deficiency;
- (2) did not represent a loss of system and/or function;
- (3) did not represent an actual loss of function of at least a single train for longer than its technical specification allowed outage time; and
- (4) did not result in the loss of a high safety-significant non-technical specification train The finding was assigned a human performance cross-cutting aspect associated with consistent processes, in that the licensee did not use a systematic approach in properly assessing the potential risk significance of an increasing trend of nitrogen leakage inside containment [H.13].
Enforcement.
Title 10 CFR Part 50, Appendix B, Criterion XVI, requires, in part, that measures shall be established to assure that conditions adverse to quality are promptly identified and corrected. Contrary to the above, between December 1, 2016, and July 28, 2017, the licensee failed to identify and correct a condition adverse to quality by not correcting the cause of excessive nitrogen leakage into Unit 2 containment.
Subsequently, excessive nitrogen leakage resulted in the IDLH conditions inside Unit 2 containment and the inoperability of a safety-related PORV for greater than technical specification allowed outage time. In response to this issue, in addition to the immediate actions noted above, the licensee initiated Notification 50934650, initiatied an equipment failure cause evaluation, a root cause evaluation, and made repairs of nitrogen supply components including relief valve RV-355. Because this violation was of very low safety significance and was entered into the licensees corrective action program, it is being treated as a non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
NCV 05000323/2017003-01, Inadequate Corrective Actions resulted in a Failure to Comply with Technical Specification 3.4.11 and an Emergency Declaration
1R18 Plant Modifications
a. Inspection Scope
On September 12-14, 2017, the inspectors reviewed a temporary plant modification to the Unit 2, nuclear power range instrumentation in support of troubleshooting, as documented in Notification 50907728. The inspectors verified that the licensee had installed this temporary modification in accordance with technically adequate design documents. The inspectors verified that this modification did not adversely impact the operability or availability of affected SSCs. The inspectors reviewed design documentation and plant procedures affected by the modification to verify the licensee maintained configuration control.
These activities constituted completion of one sample of temporary modifications, as defined in Inspection Procedure 71111.18.
b. Findings
No findings were identified.
1R19 Post-Maintenance Testing
a. Inspection Scope
The inspectors reviewed five post-maintenance testing activities that affected risk-significant SSCs:
- July 17, 2017, Unit 2, residual heat removal pump 2-1, pump motor preventative maintenance and post-maintenance testing, Work Order 64155680
- July 19, 2017, Units 1 and 2, emergency diesel generator transfer pump 0-2 maintenance, Work Order 64145012
- July 26-27, 2017, Unit 1, auxiliary saltwater cooling pump 1-1, packing replacement and preventative maintenance post-maintenance testing, Work Order 64178991
- August 2, 2017, Unit 2, test of backup nitrogen accumulator for PCV-455C, pressurizer PORV following replacement accumulator of relief valve of RV-355, Work Order 60103127
- August 26-28, 2017, Unit 2 emergency diesel generator 2-3, maintenance and post-maintenance testing, Work Order 64186067 The inspectors reviewed licensing- and design-basis documents for the SSCs and the maintenance and post-maintenance test procedures. The inspectors observed the performance of the post-maintenance tests to verify that the licensee performed the tests in accordance with approved procedures, satisfied the established acceptance criteria, and restored the operability of the affected SSCs.
These activities constituted completion of five post-maintenance testing inspection samples, as defined in Inspection Procedure 71111.19.
b. Findings
No findings were identified.
1R22 Surveillance Testing
a. Inspection Scope
The inspectors observed four risk-significant surveillance tests and reviewed test results to verify that these tests adequately demonstrated that the SSCs were capable of performing their safety functions:
In-service tests:
- July 17, 2017, Unit 2, exercising residual heat removal pump 2-1, suction valve 8700A, per procedure STP V-3M4A Other surveillance tests:
- July 6, 2017, Unit 1, exercising full length control rods, per procedure STP R-1A
- August 23, 2017, Unit 2, 4 kV Bus F, emergency diesel generator start under voltage relay testing, per procedure STP M-75F
- September 20, 2017, Unit 2, auxiliary salt water pump 2-1 routine surveillance, per procedure STP P-ASW-21 The inspectors verified that these tests met technical specification requirements, that the licensee performed the tests in accordance with their procedures, and that the results of the test satisfied appropriate acceptance criteria. The inspectors verified that the licensee restored the operability of the affected SSCs following testing.
These activities constituted completion of four surveillance testing inspection samples, as defined in Inspection Procedure 71111.22.
b. Findings
No findings were identified.
Cornerstone: Emergency Preparedness
RADIATION SAFETY
Cornerstones: Public Radiation Safety and Occupational Radiation Safety
2RS2 Occupational ALARA Planning and Controls
a. Inspection Scope
The inspectors assessed licensee performance with respect to maintaining individual and collective radiation exposures ALARA. The inspectors performed this portion of the attachment as a post-outage review. During the inspection the inspectors interviewed licensee personnel, reviewed licensee documents, and evaluated licensee performance in the following areas:
- Radiological work planning, including work activities of exposure significance, and radiological work planning ALARA evaluations, initial and revised exposure estimates, and exposure mitigation requirements. The inspectors also verified that the licensees planning identified appropriate dose reduction techniques, reviewed any inconsistencies between intended and actual work activity doses, and determined if post-job (work activity) reviews were conducted to identify lessons learned.
- Verification of dose estimates and exposure tracking systems, including the basis for exposure estimates, and measures to track, trend, and if necessary reduce occupational doses for ongoing work activities. The inspectors evaluated the licensees method for adjusting exposure estimates and reviewed the licensees evaluations of inconsistent or incongruent results from the licensees intended radiological outcomes.
- Problem identification and resolution for ALARA planning. The inspectors reviewed audits, self-assessments, and corrective action program documents to verify problems were being identified and properly addressed for resolution.
These activities constitute completion of three of the five required samples of occupational ALARA planning and controls program, as defined in Inspection Procedure 71124.02, and completes the inspection.
b. Findings
No findings were identified.
2RS4 Occupational Dose Assessment
a. Inspection Scope
The inspectors evaluated the accuracy and operability of the licensees personnel monitoring equipment, verified the accuracy and effectiveness of the licensees methods for determining total effective dose equivalent, and verified that the licensee was appropriately monitoring occupational dose. The inspectors interviewed licensee personnel, walked down various portions of the plant, and reviewed licensee performance in the following areas:
- Source term characterization, including characterization of radiation types and energies, hard-to-detect isotopes, and scaling factors.
- External dosimetry including National Voluntary Laboratory Accreditation Program (NVLAP) accreditation, storage, issue, use, and processing of active and passive dosimeters.
- Internal dosimetry, including the licensees use of whole body counting, use of in vitro bioassay methods, dose assessments based on airborne monitoring, and the adequacy of internal dose assessments.
- Special dosimetric situations, including declared pregnant workers, dosimeter placement and assessment of effective dose equivalent for external exposures (EDEX), shallow dose equivalent, and neutron dose assessment.
- Problem identification and resolution for occupational dose assessment. The inspectors reviewed audits, self-assessments, and corrective action program documents to verify problems were being identified and properly addressed for resolution.
These activities constitute completion of the five required samples of occupational dose assessment program, as defined in Inspection Procedure 71124.04.
b. Findings
No findings were identified.
OTHER ACTIVITIES
Cornerstones: Initiating Events, Mitigating Systems, Barrier Integrity, Emergency Preparedness, Public Radiation Safety, Occupational Radiation Safety, and Security
4OA1 Performance Indicator Verification
.1 Mitigating Systems Performance Index: Heat Removal Systems (MS08)
a. Inspection Scope
The inspectors reviewed the licensees mitigating system performance index data for the period of July 2016 through June 2017 to verify the accuracy and completeness of the reported data. The inspectors used definitions and guidance contained in Nuclear Energy Institute Document 99-02, Regulatory Assessment Performance Indicator Guideline, Revision 7, to determine the accuracy of the reported data.
These activities constituted verification of the mitigating system performance index for heat removal systems for Units 1 and 2, as defined in Inspection Procedure 71151.
b. Findings
No findings were identified.
.2 Mitigating Systems Performance Index: Residual Heat Removal Systems (MS09)
a. Inspection Scope
The inspectors reviewed the licensees mitigating system performance index data for the period of July 2016 through June 2017 to verify the accuracy and completeness of the reported data. The inspectors used definitions and guidance contained in Nuclear Energy Institute Document 99-02, Regulatory Assessment Performance Indicator Guideline, Revision 7, to determine the accuracy of the reported data.
These activities constituted verification of the mitigating system performance index for residual heat removal systems for Units 1 and 2, as defined in Inspection Procedure 71151.
b. Findings
No findings were identified.
.3 Mitigating Systems Performance Index: Cooling Water Support Systems (MS10)
a. Inspection Scope
The inspectors reviewed the licensees mitigating system performance index data for the period of July 2016 through June 2017 to verify the accuracy and completeness of the reported data. The inspectors used definitions and guidance contained in Nuclear Energy Institute Document 99-02, Regulatory Assessment Performance Indicator Guideline, Revision 7, to determine the accuracy of the reported data.
These activities constituted verification of the mitigating system performance index for cooling water support systems for Units 1 and 2, as defined in Inspection Procedure 71151.
b. Findings
No findings were identified.
4OA2 Problem Identification and Resolution
.1 Routine Review
a. Inspection Scope
Throughout the inspection period, the inspectors performed daily reviews of items entered into the licensees corrective action program and periodically attended the licensees condition report screening meetings. The inspectors verified that licensee personnel were identifying problems at an appropriate threshold and entering these problems into the corrective action program for resolution. The inspectors verified that the licensee developed and implemented corrective actions commensurate with the significance of the problems identified. The inspectors also reviewed the licensees problem identification and resolution activities during the performance of the other inspection activities documented in this report.
b. Findings
No findings were identified.
.2 Semiannual Trend Review
a. Inspection Scope
The inspectors reviewed the licensees corrective action program, performance indicators, system health reports, margin management program reports, and other documentation to identify trends that might indicate the existence of a more significant safety issue. The inspectors verified that the licensee was taking corrective actions to address identified adverse trends.
These activities constituted completion of one semiannual trend review sample, as defined in Inspection Procedure 71152.
b. Observations and Assessments In general, the licensee has identified trends and appropriately addressed them in the CAP. The inspectors evaluated the licensee trending methodology and observed that the licensee performs ongoing assessments and quarterly detailed reviews documented in a Station Integrated Performance Monitoring report. The licensee routinely reviews cause codes, involves key organizations, operating experience, key words, and system links to identify potential trends in their data. The inspectors noted the licensees increasing use of cognitive trending in their trend reviews. The inspectors compared the licensee process results with the results of the inspectors daily screening.
c. Findings
No findings were identified.
.3 Annual Follow-up of Selected Issues
a. Inspection Scope
The inspectors selected one issue for an in-depth follow-up:
- On September 26, 2017, Diablo Canyon structures monitoring program The inspectors reviewed Diablo Canyon Power Plants structures monitoring program. As part of the inspection, the inspectors assessed PG&Es baseline and periodic structures monitoring walkdowns, and compared structural indications identified by the inspectors to those identified by PG&E during the periodic and baseline walkdowns. The inspectors interviewed PG&E engineering personnel and reviewed program procedures and documentation.
These activities constituted completion of one annual follow-up sample as defined in Inspection Procedure 71152.
b. Findings
No findings were identified.
4OA3 Follow-up of Events and Notices of Enforcement Discretion
Alert - Unit 2, due to Low Oxygen Levels inside Containment At 12:06 p.m. PDT, the licensee declared an -Alert emergency classification (NRC Event Notice 52876) due to low oxygen levels inside containment. The Alert was initiated at the site due to discovery of Unit 2 containment atmosphere reaching IDLH levels of less than 19.5 percent oxygen due to nitrogen leakageas described in Section
1R15 of this report. The resident inspector was on site at the time and was immediately
notified about the condition. The inspector responded to the control room and later to the technical support center to observe the licensees emergency response organization actions, coordination, and communication with onsite personnel and offsite agencies.
Unit 2 containment oxygen levels were restored to normal by purging the containment, and the Alert was terminated on July 28, 2017, at 6:19 p.m. PDT. The inspectors reviewed the appropriateness of the Alert classification and determined that the declaration of Unit 2 event was accurate and timely. There were no impacts to the safe operation of the plant from this event. Both reactor units remained at full power throughout the event. Based on the resident inspectors follow-up review of the causes of this event, a finding is documented in Section 1R15 of this inspection report.
a. Inspection Scope
The inspectors reviewed the below listed events for plant status and mitigating actions to:
- (1) provide input in determining the appropriate agency response in accordance with Management Directive 8.3, NRC Incident Investigation Program;
- (2) evaluate performance of mitigating systems and licensee actions; and
- (3) confirm that the licensee properly classified the event in accordance with emergency action level procedures and made timely notifications to NRC and state/governments, as required.
- July 28, 2017, Unit 2, Alert, declaration due to low oxygen level inside containment.
Documents reviewed by the inspectors are listed in the attachment.
b. Findings
No findings were identified.
These activities constituted completion of one event follow-up sample, as defined in Inspection Procedure 71153.
4OA6 Meetings, Including Exit
Exit Meeting Summary
On August 4, 2017, the inspectors presented the radiation safety inspection results (Sections 2RS2 and 2RS4) to Mr. K. Johnston, Acting Station Director, and other members of the licensee staff. The licensee acknowledged the issues presented. The licensee confirmed that any proprietary information reviewed by the inspectors had been returned or destroyed.
On October 5, 2017, the resident inspectors presented the inspection results to Mr. J. Welsch, Site Vice President, and other members of the licensee staff. The licensee acknowledged the issues presented. The licensee confirmed that any proprietary information reviewed by the inspectors had been returned or destroyed.
SUPPLEMENTAL INFORMATION
KEY POINTS OF CONTACT
Licensee Personnel
- T. Baldwin, Director, Nuclear Site Services
- J. Covey, Radiation Protection General Foreman
- D. Evans, Director, Security & Emergency Services
- P. Gerfen, Senior Director Plant Manager
- M. Ginn, Manager, Emergency Planning
- E. Halpin, Sr. Vice President, Chief Nuclear Officer Generation
- H. Hamzehee, Manager, Regulatory Services
- J. Hinds, Director, Quality Verification
- L. Hopson, Director Maintenance Services
- M. Huszarik, ALARA Foreman
- T. Irving, Manager, Radiation Protection
- K. Johnston, Director of Operations
- M. McCoy, NRC Interface, Regulatory Services
- L. Millian, Radiation Protection Supervisor
- J. Morris, Senior Advising Engineer
- C. Murry, Director Nuclear Work Management
- J. Nimick, Senior Director Nuclear Services
- A. Peck, Director, Nuclear Engineering
- S. Stoffel, Supervisor, Dosimetry
- L. Sewell, Supervisor, Radiation Protection
- A. Warwick, Supervisor, Emergency Planning
- J. Welsch, Site Vice President
LIST OF ITEMS OPENED, CLOSED, AND DISCUSSED
Opened and Closed
Inadequate Corrective Actions resulted in a Failure to Comply
- 05000323/2017003-01 NCV with Technical Specification 3.4.11 and an Emergency Declaration (Section 1R15)