IR 05000424/2020041
| ML20209A002 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 07/27/2020 |
| From: | Binoy Desai NRC/RGN-II/DRS/EB3 |
| To: | Gayheart C Southern Nuclear Operating Co |
| References | |
| IR 2020041 | |
| Download: ML20209A002 (11) | |
Text
July 27, 2020
SUBJECT:
VOGTLE ELECTRIC GENERATING PLANT UNITS 1 AND 2 - 95001 SUPPLEMENTAL INSPECTION REPORT 05000424/2020041 AND 05000425/2020041 AND ASSESSMENT FOLLOWUP LETTER
Dear Ms. Gayheart:
On June 24, 2020, the U.S. Nuclear Regulatory Commission (NRC) completed a supplemental inspection using Inspection Procedure 95001, "Supplemental Inspection Response to Action Matrix Column 2 Inputs. On June 25, 2020, the NRC inspection team discussed the results of this inspection and the implementation of your corrective actions with you and other members of your staff.
The NRC performed this inspection to review your stations actions in response to a White finding in the Emergency Preparedness cornerstone which was documented and finalized in NRC Inspection Report 05000424, 05000425/2020090. On June 8, 2020, you informed the NRC that your station was ready for the supplemental inspection.
The NRC determined that your staffs evaluation identified the cause of the finding. Specifically, they determined that the root cause (RC-1) of the White finding was the creation of inadequate calibration procedures for the containment high-range area radiation monitors in 1991. The primary corrective actions included hiring of an outside contractor to evaluate the circumstances and severity of the problem and subsequent revision of the inadequate calibration procedures.
The NRC has determined that the completed, or planned, corrective actions are sufficient to address the performance issue that led to the White Finding. Therefore, the performance issue will no longer be considered as an Action Matrix input after the end of the second quarter of 2020, in which the supplemental inspection exit meeting and regulatory performance meeting were conducted. After reviewing Vogtle's performance in addressing the White Finding which was the subject of Inspection Procedure 95001, the NRC concluded your actions met the objectives of the inspection procedure. Therefore, in accordance with the guidance in Inspection Manual Chapter 0305, Operating Reactor Assessment Program, the White Finding will only be considered in assessing plant performance for a total of four quarters. As a result, the NRC determined the performance at Vogtle Units 1 and 2 to be in the Licensee Response Column of the Reactor Oversight Process Action Matrix beginning on July 1, 2020.
No findings or violations of more than minor significance were identified during this inspection.
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 Title 10 of the Code of Federal Regulations 2.390, Public Inspections, Exemptions, Requests for Withholding.
Sincerely,
/RA/
Binoy B. Desai, Chief Engineering Branch 3 Division of Reactor Safety Docket Nos. 05000424 and 05000425 License Nos. NPF-68 and NPF-81
Enclosure:
As stated
Inspection Report
Docket Numbers: 05000424 and 05000425 License Numbers: NPF-68 and NPF-81 Report Numbers: 05000424/2020041 and 05000425/2020041 Enterprise Identifier: I-2020-041-0000 Licensee: Southern Nuclear Operating Company, Inc.
Facility: Vogtle Electric Generating Plant Units 1 and 2 Location: Waynesboro, GA Inspection Dates: June 21, 2020 to June 27, 2020 Inspectors: A. Nielsen, Senior Health Physicist W. Pursley, Health Physicist Approved By: Binoy B. Desai, Chief Engineering Branch 3 Division of Reactor Safety Enclosure
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting a 95001 supplemental inspection at Vogtle Electric Generating Plant Units 1 and 2, in accordance with the Reactor Oversight Process. The Reactor Oversight Process is the NRCs program for overseeing the safe operation of commercial nuclear power reactors. Refer to https://www.nrc.gov/reactors/operating/oversight.html for more information.
List of Findings and Violations
No findings or violations of more than minor significance were identified.
Additional Tracking Items
None.
INSPECTION SCOPES
Inspections were conducted using the appropriate portions of the inspection procedures (IPs) in effect at the beginning of the inspection unless otherwise noted. Currently approved IPs with their attached revision histories are located on the public website at http://www.nrc.gov/reading-rm/doc-collections/insp-manual/inspection-procedure/index.html. Samples were declared complete when the IP requirements most appropriate to the inspection activity were met consistent with Inspection Manual Chapter (IMC) 2515, Light-Water Reactor Inspection Program - Operations Phase. The inspectors reviewed selected procedures and records, observed activities, and interviewed personnel to assess licensee performance and compliance with Commission rules and regulations, license conditions, site procedures, and standards.
OTHER ACTIVITIES
- TEMPORARY INSTRUCTIONS, INFREQUENT AND ABNORMAL 95001 - Supplemental Inspection Response to Action Matrix Column 2 Inputs The inspectors reviewed and selectively challenged aspects of the licensees problem identification, causal analysis, and corrective actions in response to the White finding involving the failure to adequately calibrate containment high-range area radiation monitors and the resultant high bias in main control room indication. The details of this finding are documented in inspection reports 05000424, 05000425/2018004; 05000424, 05000425/2019003; 05000424, 05000425/2019090; and 05000424, 05000425/2020090.
INSPECTION RESULTS
Assessment 95001
Problem Identification.
a. Identification. The issue was identified in October of 2018 by NRC inspectors during performance of baseline IP 71124.05, Radiation Monitoring Instrumentation. The licensee correctly stated that the issue was identified by the NRC.
b. Exposure Time. The licensee determined that calibration procedures for the containment high-range area radiation monitors had been flawed since they were created in 1991. The inspectors reviewed calibration procedure revisions back to 2002 and verified that the errors had existed at least that long. All paperwork that was reviewed and all discussions with licensee staff indicated that the condition had existed since the detectors were installed.
c. Identification Opportunities. The licensee identified an opportunity in 2015 to have identified the issue during maintenance activities on detector cabling. In addition to this example, the inspectors determined that, given the age of the condition, many other opportunities to identify the problem likely existed. For example, occasions when a calibration was performed that fell out of tolerance and gain factors were adjusted, would have been an opportunity to identify and correct the problem. However, the inspectors noted that it would be unrealistic for the licensee to correctly identify every missed opportunity from 1991 - present.
d. Risk and Compliance. The NRC determined this issue was a White finding as documented in inspection report 05000424, 05000425/2020090. The licensees Root Cause Determination Report (RCDR) documented the consequences of the issue, including the potential for emergency event over-classification during certain accident scenarios and the resulting overly conservative actions taken to protect public safety (i.e. unnecessary evacuations).
NRC Assessment: The inspectors determined that the licensee appropriately evaluated and documented problem identification, including adequate considerations of identification credit, how long the condition had existed, missed opportunities for self-identification, and risk insights.
2. Causal
Analysis.
a. Methodology. The licensees RCDR utilized a systematic Barrier Analysis methodology to determine the root and contributing causes. The analysis used an Event and Causal Factor Chart to identify the events, conditions and barriers. From the conditions, causal factors were identified that ultimately revealed the root and contributing causes.
b. Level of Detail. The licensees RCDR was conducted to a level of detail commensurate with the significance and complexity of a White finding for failure to adequately calibrate radiation monitors used to make emergency action level declarations.
c. Operating Experience. Internal and external Operating Experience (OE) was evaluated by the licensee, however the use of this particular model of high-range ion chamber appears to be unique among operating nuclear power plants. Therefore, OE was of limited use in the causal analysis. The inspectors noted that the licensee submitted its own OE regarding this issue to industry peers.
d. Extent of Condition and
Cause.
The licensees RCDR evaluated extent of condition and extent of cause among other radiation monitors used for emergency and non-emergency conditions at Plant Vogtle. Due to the unique problems with calibration of this model of high-range ion chamber, no similar conditions or causal mechanisms have been identified. Some of these evaluations were still in progress at the time of inspection.
e. Safety Culture. The licensees RCDR contained an appropriate analysis of safety culture components. The RCDR determined that the root cause (RC-1) and one of the contributing causes (CC-1) was associated with the Human Performance Aspect of Resources, which aligned with the inspection finding cross cutting aspect. The RCDR also determined that both contributing causes (CC-1 and CC-2) were associated with the Supplemental Aspects of Accountability and Safety Policies.
f.
Common
Cause.
This inspection covered only one White input into the EP cornerstone, therefore a common cause analysis was not performed.
NRC Assessment: The licensees RCDR determined that the root cause (RC-1) of the performance deficiency was the creation of inadequate calibration procedures shortly after radiation monitor installation. A contributing cause (CC-1) was determined to be less than adequate understanding of the out-of-tolerance characteristics of ion chamber monitors, which contributed to missed opportunities to self-identify the issue (e.g. in 2015 during maintenance activities). A second contributing cause (CC-2) was identified as a lack of challenge from licensee management when out-of-tolerance conditions were identified (e.g. in 2015). The RCDR was performed according to licensee procedures and by qualified individuals that had no direct authority over, and were not responsible for, any of the areas evaluated. The inspectors determined that the RCDR adequately addressed the root and contributing causes of the White finding.
3. Corrective Actions.
a. Corrective Actions
to Prevent Recurrence
- (1) Completed As documented in inspection report 05000424, 05000425/2019003; the licensee hired an outside contractor to determine the degree of detector bias in the spring of 2019. The contractors report showed that the degree of bias was +60% for 2RE-005 and +84% for 2RE-006 and that the Unit 1 detectors were likely biased high by a similar amount. From April 2019 to March 2020, the licensees primary corrective action was to revise their calibration procedures based on recommendations from the contractor. The new procedures implemented a fixed, reproducible source-to-detector geometry and would allow the licensee to determine the correct gain factor for each radiation monitor. The procedure revisions successfully addressed the root cause (RC-1) of the problem and are considered corrective actions to prevent recurrence (CAPR), however these procedures could only be performed during a plant shutdown. Although the instruments continued to read high while waiting for an outage opportunity, the inspectors noted that there were no interim compensatory actions taken during this time period (e.g. adjusting the gain factors to nominal values or issuing temporary guidance to the emergency response organization). This represents a missed opportunity to take interim corrective actions prior to achieving full compliance.
As of the date of this inspection, the new calibration procedures have been performed on both units and the gain factors for all four containment high range area radiation monitors have been adjusted back to accurate values. Therefore, the artificial bias in main control room indication no longer exists. An effectiveness review metric (evaluation of calibration procedure performance) was created for this CAPR and will be assessed during subsequent refueling outages.
- (2) Planned All CAPRs have been completed.
b. Other Corrective Actions
- (1) Completed Several corrective actions taken to address contributing causes have been completed, including informal training provided by the contractor on containment high-range area radiation monitors (CC-1). Also, as a result of many issues, Southern Nuclear Corporation (SNC) executive leadership made changes to how the nuclear sites interact with SNC headquarters. One of the changes was to shift headquarters from an oversight role to more of a support role, where technical decisions are more likely to be challenged (CC-2).
- (2) Planned Planned corrective actions include assessment of the calibration procedures for different types of effluent monitors (extent of condition), performance of a training needs analysis (CC-1), and various enhancements and clarifications to the newly revised calibration procedures.
NRC Assessment: The inspectors determined that completed and planned corrective actions, including CAPRs, were adequate to address the root cause and contributing causes of the White finding. However, the inspectors identified a missed opportunity to take immediate corrective actions when presented with the contractors results in April 2019. This weakness was entered into the licensees corrective action program as condition report 10718138.
Old Design Issue Evaluation.
This issue is not being considered for treatment as an old design issue, therefore this section is omitted.
Conclusion.
The inspectors determined that the licensees causal evaluation of the White finding and corrective actions taken to address root and contributing causes have been effective and complete. All objectives listed in inspection procedure 95001 have been satisfactorily completed. Therefore, in accordance with Inspection Manual Chapter 0305, this finding is closed and the associated White input is removed from the action matrix.
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
- On June 25, 2020, the inspectors presented the 95001 Exit Meeting and Regulatory Performance Meeting inspection results to Mr. Drayton Pitts and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection Type Designation Description or Title Revision or
Procedure Date
95001 Calibration SNC788584 18M Hi Range Area Monitor 1RE-0005 Isotopic/Chan Cal 03/16/2020
Records SNC792808 18M Hi Range Area Monitor Isotopic/Chan Cal 1RE-0006 03/16/2020
Corrective Action CAR277215 Root Cause Determination Report, Containment High Range 06/15/2020
Documents Monitor Less Than Adequate Calibration Methodology
CR10536455
CR10536456
CR10550154
CR10621284
CR10695355
CR10699945
CR107092552
Corrective Action CR 10717619
Documents CR 10717859
Resulting from
Inspection
Engineering RSCS TSD 19- High-Range Containment Radiation Monitor Calibration 04/05/2019
Evaluations 023 Evaluation for Vogtle
Miscellaneous Printout from Plant Computer - Current Gain Factors for 06/08/2020
1RE-0005, 1RE-0006, 2RE-0005, and 2RE-0006.
NMP-AD-012-F01 Determination of Operability, OD V1-19-001, Lessons Revision 2
Learned, CR10621284 and CR10709252
Procedures 24989-1 Isotopic Channel Calibration of the Containment High Range Revision 1
Area Monitors 1RE-0005 and 1RE-0006
24989-1 Isotopic Channel Calibration of the Containment High Range Version 7.1
Area Monitors 1RE-0005 and 1RE-0006
24989-1 Isotopic Channel Calibration of the Containment High Range Version 9
monitors 1 RE-0005 and 1RE-0006
NMP-GM-002 Corrective Action Program Version 15.1
NMP-GM-002- Organizational and Programmatic (O&P) Screening Tool Version 8.2
F08
NMP-GM-002- Human Performance Checklist Version 10.3
F31
Inspection Type Designation Description or Title Revision or
Procedure Date
NMP-GM-002- Level of Evaluation Checklist Version 6.3
F47
NMP-GM-002- Example Barrier Analysis Version 2.3
F48
NMP-GM-002- Cause Analysis and Corrective Actions Guideline Version 30.1
GLO3
8