IR 05000282/2020012
| ML20211L852 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 07/29/2020 |
| From: | Richard Skokowski Engineering Branch 3 |
| To: | Sharp S Northern States Power Company, Minnesota |
| References | |
| IR 2020012 | |
| Download: ML20211L852 (13) | |
Text
July 29, 2020
SUBJECT:
PRAIRIE ISLAND NUCLEAR GENERATING PLANT - TRIENNIAL INSPECTION OF EVALUATION OF CHANGES, TESTS AND EXPERIMENTS BASELINE INSPECTION REPORT 05000282/2020012 AND 05000306/2020012
Dear Mr. Sharp:
On June 30, 2020, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Prairie Island Nuclear Generating Plant and discussed the results of this inspection with you and other members of your staff. The results of this inspection are documented in the enclosed report.
One finding of very low safety significance (Green) is documented in this report. This finding involved a violation of NRC requirements. We are treating this violation as a non-cited violation (NCV) consistent with Section 2.3.2 of the Enforcement Policy.
If you contest the violation or the significance or severity of the violation documented in this inspection report, 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 III; the Director, Office of Enforcement; and the NRC Resident Inspector at Prairie Island Nuclear Generating 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 III; and the NRC Resident Inspector at Prairie Island Nuclear Generating 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 Title 10 of the Code of Federal Regulations 2.390, Public Inspections, Exemptions, Requests for Withholding.
Sincerely,
/RA/
Richard A. Skokowski, Chief Engineering Branch 3 Division of Reactor Safety Docket Nos. 05000282 and 05000306 License Nos. DPR-42 and DPR-60
Enclosure:
As stated
Inspection Report
Docket Numbers: 05000282 and 05000306 License Numbers: DPR-42 and DPR-60 Report Numbers: 05000282/2020012 and 05000306/2020012 Enterprise Identifier: I-2020-012-0013 Licensee: Northern States Power Company, Minnesota Facility: Prairie Island Nuclear Generating Plant Location: Red Wing, Minnesota Inspection Dates: June 22, 2020 to June 30, 2020 Inspectors: J. Gilliam, Physical Security Inspector M. Holmberg, Senior Reactor Inspector V. Petrella, Reactor Inspector Approved By: Richard A. Skokowski, 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 triennial inspection of evaluation of changes, tests and experiments baseline inspection at Prairie Island Nuclear Generating Plant, 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
Failure to Preclude Load Following Operations to Assure Rod Cluster Control Assembly Functions Cornerstone Significance Cross-Cutting Report Aspect Section Mitigating Green [H.6] - Design 71111.17T Systems NCV 05000282/2020012-01 Margins Open/Closed The inspectors identified a finding of very low safety significance (Green) and an associated Non-Cited Violation of 10 CFR Part 50, Appendix B, Criterion III, Design Control, when the licensee failed to incorporate a restriction to prohibit load following into plant procedures.
This operating procedure restriction was necessary to ensure that the Rod Cluster Control Assembly (RCCA) design functions would be maintained beyond 12 effective full power years (EFPY).
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.
REACTOR SAFETY
71111.17T - Evaluations of Changes, Tests, and Experiments Sample Selection (IP Section 02.01)
The inspectors reviewed the following evaluations, screenings, and/or applicability determinations for 10 CFR 50.59 from June 22, 2020, through June 30, 2020.
- (1) Evaluation 1145, Digital Upgrade of Feedwater and AMSAC/DSS Control Systems
- (2) Evaluation 1149, Post High Energy Line Break Battery Room Cooling
- (3) Screening 5480, D5 D6 Under Voltage Trip Logic Change
- (4) Screening 5439, Bypass D5 and D6 Crankcase Pressure Switch
- (6) Applicability Determination 6326, Changes to U-2 Emergency Diesel Generator Procedures to Address Temperature Limitations
- (7) Applicability Determination 3096, License Amendment Request Technical Specification Change 607000000180
- (8) Evaluation 1141, Instrument Air Containment Isolation Valve Redundant Solenoid Air Supply
- (9) Evaluation 1144, Incorporate Supplemental Updated Safety Analysis Chapter 14.5.6 Rod Cluster Control Assembly Ejection Analysis
- (10) Evaluation 1151, Revision to Post-Accident Exclusion Area Boundary, Low Population Zone, and Control Room Doses
- (11) Screening 5522, Reactor Coolant Pump Casing Thermal Fatigue Heatup and Cooldown Cycles
- (12) Screening 5535, Revision to Updated Safety Analysis Report Section 12.2.1.3.1
- (13) Screening 5547, PCR 1 C4.2 Reactor Coolant System Inventory Control - Post Refueling
- (14) Screening 5553, Incorporation of Industry Reactor Vessel Internals Baffle Former Bolt Guidance
- (15) Screening 5590, Change Normal Position of Residual Heat Removal Pit Covers to OPEN- ECR 601000001267 / Calculation GEN-Pl-085
- (16) Screening 5498, Instrument Air Containment Isolation Valve Redundant Solenoid Air Supply
- (17) Screening 5555, Incorporate Supplemental Updated Safety Analysis Chapter 14.5.6 RCCA Ejection Analysis
- (18) Applicability Determination 6418, Updated Safety Analysis Report Chapter 4 Revision for Reactor Vessel Surveillance Capsule Removal Schedule Change
- (19) Applicability Determination 6444, 600000567786 & 600000567753 - TP 1568 and TP 2568 Ads Reactivity Plan Monthly Update - Unit 1/2
- (20) Screening 5634, Turbine Overspeed Protection Test Frequency Changes
- (21) Evaluation 1153, Turbine Overspeed Protection Test Frequency Changes
- (22) Screening 5584, D1 and D2 Diesel Generator Undervoltage Start Condition Trip Logic Change
- (23) Evaluation 1147, D1 and D2 Generator Logic Change
- (24) Screening 5526, Revised Turbine Building & Auxiliary Building HELB Heat Up Calculations
- (25) Evaluation 1143, Changes to C18.1 to Incorporate Manual Actions as Compensatory Measures
- (26) Screening 5573, ENG-ME-856 revision 0, D5/D6 Lube Oil Heat Exchanger Tube Plugging
- (27) Screening 5557, Update calculations ENG-ME-005, 2005-02881, and the USAR to Reflect Tech Spec Minimum 90% RWST Level
- (28) Screening 5546, Downgrade 2 of 4 Containment Dome Recirc Fans in Each Unit
- (29) Screening 5447, D 104.2 Zebra Mussel Control Treatment: Thermal Treatment (New)
- (30) Applicability Determination 3017, Rod Position Indication Cold Calibration
- (31) Applicability Determination 3003, Revise Turnover Strategy for EC 26419, AFWP Room Coolers
- (32) Screening 5606, ZX System Biocide
- (33) Screening 5502, Change the All Rods Out Position of the Unit 1 Control Rods
INSPECTION RESULTS
Failure to Preclude Load Following Operations to Assure Rod Cluster Control Assembly Functions Cornerstone Significance Cross-Cutting Report Aspect Section Mitigating Green [H.6] - Design 71111.17T Systems NCV 05000282/2020012-01 Margins Open/Closed The inspectors identified a finding of very low safety significance (Green) and an associated Non-Cited Violation of 10 CFR Part 50, Appendix B, Criterion III, Design Control, when the licensee failed to incorporate a restriction to prohibit load following into plant procedures.
This operating procedure restriction was necessary to ensure that the Rod Cluster Control Assembly (RCCA) design functions would be maintained beyond 12 effective full power years (EFPY).
Description:
A RCCA, also known as (a.k.a.) a control rod, consists of a group of individual absorber rods (a.k.a., rodlets) held together by a spider type hub at the top end. Each rodlet is comprised of silver-indium-cadmium rods inserted into a cold-worked stainless steel tube and sealed at the bottom and the top by a welded end plug. In the inserted position, the absorber rodlets fit within hollow guide thimbles within the fuel assemblies. The guide thimbles are an integral part of the fuel assemblies and occupy locations within the regular fuel rod pattern where fuel rods have been deleted. The RCCA are typically controlled and actuated as a group or bank. The RCCA design functions include: achieving full insertion into the fuel assembly throughout active lifetime, maintaining structural integrity, and providing sufficient reactivity worth to shut down the reactor.
In screening 5502, Change the All Rods Out Position of the Unit 1 Control Rods, the license concluded that the change in the all rods out position from 228 steps to 225 steps, as documented in engineering evaluation 6EVA00028156, was not an adverse change and therefore did not require a 10 CFR 50.59 evaluation. On May 4, 2018, the licensee approved engineering evaluation 6EVA00028156, which incorporated results from a vendor analysis NF-XCEL-16-79, XCEL ENERGY Prairie Island Nuclear Generating Plant Transmitting Review of RCCA Lifetime at Prairie Island that established acceptance criteria for minimum cladding thickness, maximum rodlet diameter, and cracking. The licensees vendor established these acceptance criteria to assure continued RCCA design functions given the change in all rods out position and extension of the RCCA design life from 12 EFPY to 15 EFPY.
As of June 2019, the licensee had operated Unit 1 beyond 12 EFPY and thus was relying on the vendor analysis NF-XCEL-16-79 to assure the capability of the RCCA to perform design functions. In NF-XCEL-16-79, the vendor identified Base load operation (not load follow) as a restriction that supported the vendors swelling model used to calculate the rodlet swelling (e.g., increase in diameter) caused by absorption of neutrons (e.g., fluence) over the RCCA extended lifetime (e.g., 15 EFPY). This operating restriction/assumption precluded additional absorbed neutron fluence and swelling of rodlets that would occur during load following operations/flexible power operations as the RCCA are intermittently inserted into fuel assemblies. However, the licensee did not incorporate this vendor restriction into operating procedures and had performed flexible power operations (a.k.a., load following) more than 30 times in Unit 1 since September 3, 2019. Therefore, the RCCA rodlets may have experienced swelling beyond that considered in the licensees vendor analysis which could adversely impact the capability of the RCCA to perform design functions.
Corrective Actions: The licensee entered this issue into the corrective action program as Quality Issue 501000041863 and implemented actions to ensure that Unit 2 would not perform flexible power operations until completion of a prompt operability determination and established controls to ensure Unit 1 would not undergo flexible power operations until after the next refueling outage. The licensee completed a prompt operability determination and concluded that the Unit 1 RCCA were operable based on: the margin available between the assessment assumptions and actual operation, the control rod drop times were within the acceptance criteria, the control rods successful drag test, the last performance of the quarterly control rod exercise testing was satisfactory, all rod-to-rod and rod to bank deviations were within Technical Specification limits and there were no anomalies noted during the last flexible power operation on Unit 1 on May 2, 2020.
Corrective Action References: Quality Issue 501000041863, Ctrl Rod Lifetime Extension Assumptions
Performance Assessment:
Performance Deficiency: The inspectors determined that the licensees failure to incorporate a restriction to prohibit load following (a.k.a., flexible power operations) into plant procedures was contrary to 10 CFR Part 50, Appendix B, Criterion III and a performance deficiency.
Screening: The inspectors determined the performance deficiency was more than minor because if left uncorrected, it would have the potential to lead to a more significant safety concern. Specifically, if left uncorrected, the failure to assure that operating procedures incorporated a restriction for no load following could have allowed continued swelling of the rodlets such that the RCCA may not have been able to perform safety functions and/or caused RCCA binding that would complicate a plant shutdown.
Significance: The inspectors assessed the significance of the finding using Appendix A, The Significance Determination Process (SDP) for Findings At-Power. Specifically, the inspectors determined the finding was very low safety significance (Green) because the inspectors answered NO to question C of Exhibit 2, Mitigating Systems Screening Questions.
Cross-Cutting Aspect: H.6 - Design Margins: The organization operates and maintains equipment within design margins. Margins are carefully guarded and changed only through a systematic and rigorous process. Special attention is placed on maintaining fission product barriers, defense-in-depth, and safety related equipment. Specifically, the licensees failure to incorporate a restriction to prohibit load following into plant procedures reduced the design margins that were established that assure RCCA design functions were maintained.
Enforcement:
Violation: Title 10 CFR Part 50, Appendix B, Criterion III, Design Control, requires in part, that measures shall be established to assure that applicable regulatory requirements and the design basis, as defined in 10 CFR 50.2 and as specified in the license application, for those structures, systems, and components to which this appendix applies are correctly translated into specifications, drawings, procedures, and instructions.
Contrary to the above, from September 3, 2019, through June 25, 2020, the licensee failed to correctly translate applicable design basis requirements into procedures and instructions.
Specifically, the licensee did not correctly translate the no load following design restriction into operating procedures and this was necessary to assure the safety-related RCCA would continue to be able to perform design functions beyond 12 EFPY.
Enforcement Action: This violation is being treated as an non-cited violation, consistent with Section 2.3.2 of the Enforcement Policy.
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
- On June 30, 2020, the inspectors presented the triennial inspection of evaluation of changes, tests and experiments baseline inspection results to Scott Sharp and other members of the licensee staff.
DOCUMENTS REVIEWED
Inspection Type Designation Description or Title Revision or
Procedure Date
71111.17T Calculations 32-9203487 Pl-2 RCS Load and Stress Analyses Considering the RSGs 0
and MUR Conditions
CN-TA-07-114 Prairie Island Units 1 and 2 (NSP/NRP) Rod Ejection 1
Analysis for 422V+ (Heavy Bundle) Fuel Transition
Program - Supplemental Reanalysis for Gad Fuel with
Reduced Power Suppression
GEN-Pl-085 Post-LOCA Vital Area Mission Doses Using AST 1
WCAP-7588 An Evaluation of the Rod Ejection Accident in Westinghouse 1-A
Pressurized Water Reactors Using Spatial Kinetic Methods
Corrective Action 501000001209 NSP-17-17: NSAL-17-3 Westinghouse Model 07/28/2017
Documents 501000002397 APC #2644 >30 days need 50.59 screening 09/08/2017
501000007210 APC #2686 >45 days need 50.59 screening 03/16/2018
501000009048 NOS ID: 72.48 Screen Documentation Error 03/02/2018
501000009195 USAR Chapter 14.5 Needs Updating 03/06/2018
501000013629 NOS ID: Equiv 50.59 Reqts not documented 06/26/2018
501000028120 ZX System microbes 06/04/2019
501000037432 2020 50.59 FSA USAR updates for AST 04/07/2020
501000039513 NOS: 50.59 AD/Prescreen Basis 04/08/2020
604000000431 USAR Section 7.5.5 & USAR Section 12.3.4 03/11/2020
Corrective Action 501000040868 2020 50.59 - Reviews of Fleet Documents 05/22/2020
Documents 501000041759 2020 50.59 - Editorial errors GEN-PI-085 06/22/2020
Resulting from 501000041841 2020 50.59 insp Table 2.0-1 of CN-TA-07 06/24/2020
Inspection 501000041846 2020 50.59 - Screening 5547 inadequacies 06/25/2020
501000041863 Ctrl Rod Lifetime Ext Assumptions 06/25/2020
501000041863 Ctrl Rod Lifetime Ext Assumptions 06/25/2020
501000041890 2020 50.59 - Observation on USAR Update 06/25/2020
Drawings NF-38110 PINGP RHR Pit Covers for Unit 1 and Unit 2 A
NF-38298-18 Auxiliary Bld Concrete RHR Pit Cover Slab Plan and Section H
Unit 1
Engineering 601000000824 123 Cooling Tower Refurbishment, Header Replacement, 0
Changes and Fan Skid Upgrade
Inspection Type Designation Description or Title Revision or
Procedure Date
601000002138 Temporary Supports for Control Room Chiller Purge 0
Compressor Tank
ECR Instrument Air Containment Isolation Valve SV Bypass 0
601000000133
Miscellaneous Closure Notes for OBN 01265904-07 0
1141 Safety Evaluation - Instrument Air CIV Redundant Solenoid 0
Air Supply
1143 Safety Evaluation - Changes to C18.1 to incorporate manual 1
actions as compensatory measures
1144 Safety Evaluation - Incorporate Supplemental UFSAR 0
Chapter 14.5.6 RCCA Ejection Analysis
1145 Evaluation- Digital Upgrade of FW and AMSAC/DSS Control 0
Systems
1147 Safety Evaluation - D1 and D2 Generator Logic Change 0
1149 Safety Evaluation- Post HELB Battery Room Cooling 0
1151 Safety Evaluation - Revision to Post-Accident EAB, LPZ, and 0
CR Doses
1153 Safety Evaluation - Turbine Overspeed Protection Test 0
Frequency Changes
3003 Applicability Determination - Revise Turnover Strategy for 0
EC 26419 AFWP Room Coolers
3017 Applicability Determination - Rod Position Indication Cold 0
Calibration
3096 Applicability Determination- LAR Tech Spec Change 1
607000000180
5439 Screening- Bypass D6 Crankcase Pressure Trips to support 1
Operations
5447 Screening - D 104.2 Zebra Mussel Control Treatment: 0
Thermal Treatment (New)
5480 Screening - D5 D6 Under Voltage Trip Logic Change 0
5498 Screening - Instrument Air CIV Redundant Solenoid Air 0
Supply
5502 Screening - Change the All Rods Out Position of the Unit 1 0
Inspection Type Designation Description or Title Revision or
Procedure Date
22 Screening - RCP Casing Thermal Fatigue Heatup and 0
Cooldown Cycles
26 Screening - Revised Turbine Building & Auxiliary Building 3
HELB Heat Up Calculations
5535 Screening - Revision to USAR Section 12.2.1.3.1 0
5546 Screening - Downgrade 2 of 4 Containment Dome Recirc 0
Fans in each unit
5547 Screening - PCR 1 C4.2 RCS Inventory Control Post 0
Refueling -POST Refueling
5553 Screening - Incorporation of Industry RV Internals BFB 0
Guidance
5555 Screening - Incorporate Supplemental UFSAR Chapter 0
14.5.6 RCCA Ejection Analysis
5557 Screening - Update calculations ENG-ME-005, 2005-02881, 0
and the USAR to reflect Tech Spec minimum 90% RWST
level
5573 Screening - ENG-ME-856 revision 0, D5/D6 Lube Oil Heat 0
Exchanger Tube Plugging
5584 Screening - D1 and D2 Diesel Generator Undervoltage Start 0
Condition Trip Logic Change
5590 Screening - Change normal position of RHR Pit covers to 0
OPEN- ECR 601000001267 / Calculation GEN-Pl-085
5606 Screening - ZX System Biocide 0
5634 Screening - Turbine Overspeed Protection Test Frequency 0
Changes
5644 Screening- 601000001083 DC Calculations Major Revision 0
2000008479 Training Assessment C18.1 Rev 54 ECR 601000001545 06/12/2018
606000001204 Focused Self-Assessment Plan and Report -Triennial 02/07/2020
Modifications/50.59 (IP 71111.17T)
26 Applicability Determination - Changes to U-2 Emergency 0
Diesel Generator Procedures to Address Temperature
Limitations
6418 Applicability Determination - USAR Ch 4 Revision for RV 0
Surveillance Capsule Removal Schedule Change
Inspection Type Designation Description or Title Revision or
Procedure Date
6444 Applicability Determination - 600000567786 & 0
600000567753 - TP 1568 and TP 2568 Ads Reactivity Plan
Monthly Update - Unit 1/2
6EVA00028156 Change All Rods Out Position For Unit 1 02/26/2019
I&M V9629R2 Solenoid Valves used in Safety Instrumented Systems 2
L-2019-LLL-0002 Prairie Island Nuclear Generating Plant, Units 1 and 2 - 07/03/2019
Reactor Vessel Material Surveillance Capsule Withdrawal
Schedules
NF-XCEL-16-79 Xcel Energy Prairie Island Nuclear Generating Plant 11/11/2016
Transmitting Review of RCCA Lifetime at Prairie Island
NF-XCEL-17-1 Xcel Energy Prairie Island Nuclear Generation Plant Prairie 01/17/2017
Island Units 1 and 2 RCCA Lifetime Extension Responses
NF-XCEL-17-14 Xcel Energy Prairie Island Nuclear Generation Plant Safety 04/07/2017
Analysis Confirmation of ARO Parking Position Change for
Prairie Island
NX-18809-1 ASCO Solenoid Valves 12
WCAP-9272-P-A Westinghouse Reload Safety Evaluation Methodology 07/01/1985
Procedures 1C4.2 RCS Inventory Control -Post Refueling 40
FG-E-SE-03 50.59 Resource Manual 9
FP-E-SE-03 10 CFR 50.59 and 72.48 Processes 16
H29 Metal Fatigue Management Program 13
SP 1173 Stress Cycle Record - Unit 1 46
SP 2173 Stress Cycle Record - Unit 2 45
TP 1568 Reactivity Plan Monthly Update - Unit 1 6
TP 2568 Reactivity Plan Monthly Update - Unit 2 6
Work Orders 700035054 CV-31740: Install Bypass EC601000000133 03/13/2019
10