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:
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
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 Aspect Report Section Mitigating Systems Green NCV 05000282/2020012-01 Open/Closed
[H.6] - Design Margins 71111.17T 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 Aspect Report Section Mitigating Systems
Green NCV 05000282/2020012-01 Open/Closed
[H.6] - Design Margins 71111.17T 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
Procedure
Type
Designation
Description or Title
Revision or
Date
71111.17T Calculations
2-9203487
Pl-2 RCS Load and Stress Analyses Considering the RSGs
and MUR Conditions
CN-TA-07-114
Prairie Island Units 1 and 2 (NSP/NRP) Rod Ejection
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
An Evaluation of the Rod Ejection Accident in Westinghouse
Pressurized Water Reactors Using Spatial Kinetic Methods
1-A
Corrective Action
Documents
501000001209
NSP-17-17: NSAL-17-3 Westinghouse Model
07/28/2017
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
20 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
Documents
Resulting from
Inspection
501000040868
20 50.59 - Reviews of Fleet Documents
05/22/2020
501000041759
20 50.59 - Editorial errors GEN-PI-085
06/22/2020
501000041841
20 50.59 insp Table 2.0-1 of CN-TA-07
06/24/2020
501000041846
20 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
20 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
Unit 1
H
Engineering
Changes
601000000824
23 Cooling Tower Refurbishment, Header Replacement,
and Fan Skid Upgrade
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
601000002138
Temporary Supports for Control Room Chiller Purge
Compressor Tank
601000000133
Instrument Air Containment Isolation Valve SV Bypass
Miscellaneous
Closure Notes for OBN 01265904-07
1141
Safety Evaluation - Instrument Air CIV Redundant Solenoid
Air Supply
1143
Safety Evaluation - Changes to C18.1 to incorporate manual
actions as compensatory measures
1144
Safety Evaluation - Incorporate Supplemental UFSAR
Chapter 14.5.6 RCCA Ejection Analysis
1145
Evaluation-Digital Upgrade of FW and AMSAC/DSS Control
Systems
1147
Safety Evaluation - D1 and D2 Generator Logic Change
1149
Safety Evaluation-Post HELB Battery Room Cooling
1151
Safety Evaluation - Revision to Post-Accident EAB, LPZ, and
CR Doses
1153
Safety Evaluation - Turbine Overspeed Protection Test
Frequency Changes
3003
Applicability Determination - Revise Turnover Strategy for
EC 26419 AFWP Room Coolers
3017
Applicability Determination - Rod Position Indication Cold
Calibration
3096
Applicability Determination-LAR Tech Spec Change
607000000180
5439
Screening-Bypass D6 Crankcase Pressure Trips to support
Operations
5447
Screening - D 104.2 Zebra Mussel Control Treatment:
Thermal Treatment (New)
5480
Screening - D5 D6 Under Voltage Trip Logic Change
5498
Screening - Instrument Air CIV Redundant Solenoid Air
Supply
5502
Screening - Change the All Rods Out Position of the Unit 1
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
22
Screening - RCP Casing Thermal Fatigue Heatup and
Cooldown Cycles
26
Screening - Revised Turbine Building & Auxiliary Building
HELB Heat Up Calculations
5535
Screening - Revision to USAR Section 12.2.1.3.1
5546
Screening - Downgrade 2 of 4 Containment Dome Recirc
Fans in each unit
5547
Screening - PCR 1 C4.2 RCS Inventory Control Post
Refueling -POST Refueling
5553
Screening - Incorporation of Industry RV Internals BFB
Guidance
5555
Screening - Incorporate Supplemental UFSAR Chapter
14.5.6 RCCA Ejection Analysis
5557
Screening - Update calculations ENG-ME-005, 2005-02881,
and the USAR to reflect Tech Spec minimum 90% RWST
level
5573
Screening - ENG-ME-856 revision 0, D5/D6 Lube Oil Heat
Exchanger Tube Plugging
5584
Screening - D1 and D2 Diesel Generator Undervoltage Start
Condition Trip Logic Change
5590
Screening - Change normal position of RHR Pit covers to
OPEN-ECR 601000001267 / Calculation GEN-Pl-085
5606
Screening - ZX System Biocide
5634
Screening - Turbine Overspeed Protection Test Frequency
Changes
5644
Screening-601000001083 DC Calculations Major Revision
2000008479
Training Assessment C18.1 Rev 54 ECR 601000001545
06/12/2018
606000001204
Focused Self-Assessment Plan and Report -Triennial
Modifications/50.59 (IP 71111.17T)
2/07/2020
26
Applicability Determination - Changes to U-2 Emergency
Diesel Generator Procedures to Address Temperature
Limitations
6418
Applicability Determination - USAR Ch 4 Revision for RV
Surveillance Capsule Removal Schedule Change
Inspection
Procedure
Type
Designation
Description or Title
Revision or
Date
6444
Applicability Determination - 600000567786 &
600000567753 - TP 1568 and TP 2568 Ads Reactivity Plan
Monthly Update - Unit 1/2
6EVA00028156
Change All Rods Out Position For Unit 1
2/26/2019
I&M V9629R2
Solenoid Valves used in Safety Instrumented Systems
Prairie Island Nuclear Generating Plant, Units 1 and 2 -
Reactor Vessel Material Surveillance Capsule Withdrawal
Schedules
07/03/2019
NF-XCEL-16-79
Xcel Energy Prairie Island Nuclear Generating Plant
Transmitting Review of RCCA Lifetime at Prairie Island
11/11/2016
NF-XCEL-17-1
Xcel Energy Prairie Island Nuclear Generation Plant Prairie
Island Units 1 and 2 RCCA Lifetime Extension Responses
01/17/2017
NF-XCEL-17-14
Xcel Energy Prairie Island Nuclear Generation Plant Safety
Analysis Confirmation of ARO Parking Position Change for
Prairie Island
04/07/2017
NX-18809-1
ASCO Solenoid Valves
Westinghouse Reload Safety Evaluation Methodology
07/01/1985
Procedures
1C4.2
RCS Inventory Control -Post Refueling
FG-E-SE-03
50.59 Resource Manual
FP-E-SE-03
CFR 50.59 and 72.48 Processes
H29
Metal Fatigue Management Program
SP 1173
Stress Cycle Record - Unit 1
SP 2173
Stress Cycle Record - Unit 2
TP 1568
Reactivity Plan Monthly Update - Unit 1
TP 2568
Reactivity Plan Monthly Update - Unit 2
Work Orders
700035054
CV-31740: Install Bypass EC601000000133
03/13/2019