ML23033A333
| ML23033A333 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 02/02/2023 |
| From: | Jon Greives NRC/RGN-I/DORS |
| To: | Rhoades D Constellation Energy Generation, Constellation Nuclear |
| References | |
| IR 2022004 | |
| Download: ML23033A333 (1) | |
See also: IR 05000277/2022004
Text
February 2, 2023
David P. Rhoades
Senior Vice President
Constellation Energy Generation, LLC
President and Chief Nuclear Officer (CNO)
Constellation Nuclear
4300 Winfield Road
Warrenville, IL 60555
SUBJECT: PEACH BOTTOM ATOMIC POWER STATION, UNITS 2 AND 3 -
INTEGRATED INSPECTION REPORT 05000277/2022004 AND
Dear David Rhoades:
On December 31, 2022, the U.S. Nuclear Regulatory Commission (NRC) completed an
inspection at Peach Bottom Atomic Power Station, Units 2 and 3. On January 20, 2023, the
NRC inspectors discussed the results of this inspection with Ron DiSabatino, Plant Manager,
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 I; the Director, Office of Enforcement; and the NRC Resident Inspector at
Peach Bottom Atomic Power Station, Units 2 and 3.
D. Rhoades 2
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,
Digitally signed by Jonathan E.
Jonathan E. Greives
Date: 2023.02.02 11:21:44
Greives -05'00'
Jonathan E. Greives, Chief
Projects Branch 4
Division of Operating Reactor Safety
Docket Nos. 05000277 and 05000278
License Nos. DPR-44 and DPR-56
Enclosure:
As stated
cc w/ encl: Distribution via LISTSERV
x Non-Sensitive x Publicly Available
x SUNSI Review
Sensitive Non-Publicly Available
OFFICE Rl/DORS Rl/DORS
NAME SRutenkroger JGreives
DATE 2/2/23 2/1/23
U.S. NUCLEAR REGULATORY COMMISSION
Inspection Report
Docket Numbers: 05000277 and 05000278
License Numbers: DPR-44 and DPR-56
Report Numbers: 05000277/2022004 and 05000278/2022004
Enterprise Identifier: I-2022-004-0039
Licensee: Constellation Energy Generation, LLC
Facility: Peach Bottom Atomic Power Station, Units 2 and 3
Location: Delta, PA 17314
Inspection Dates: October 1, 2022 to December 31, 2022
Inspectors: S. Rutenkroger, Senior Resident Inspector
C. Dukehart, Resident Inspector
L. Casey, Senior Allegations Coordinator
N. Eckhoff, Health Physicist
B. Edwards, Health Physicist
C. Hobbs, Reactor Inspector
K. Mangan, Senior Reactor Inspector
N. Mentzer, Resident Inspector
A. Turilin, Reactor Inspector
A. Ziedonis, Senior Resident Inspector
Approved By: Jonathan E. Greives, Chief
Projects Branch 4
Division of Operating Reactor Safety
Enclosure
SUMMARY
The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees
performance by conducting an integrated inspection at Peach Bottom Atomic Power Station,
Units 2 and 3, 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 Implement an Effective Maintenance Strategy for Unit 2 and Unit 3 Residual Heat
Removal System Agastat Relays
Cornerstone Significance Cross-Cutting Report
Aspect Section
Mitigating Green None (NPP) 71152A
Systems NCV 05000277,05000278/2022004-01
Open/Closed
The inspectors identified a Green finding and associated non-cited violation (NCV) of
Technical Specification (TS) 5.4.1.a, "Procedures," and Regulatory Guide (RG) 1.33, for
Constellation's failure to establish an effective maintenance strategy for Agastat control relays
in the safety-related residual heat removal (RHR) system at both Peach Bottom Unit 2 and
Peach Bottom Unit 3. RG 1.33, Appendix A, November 1972,Section I, requires in part, that
preventive maintenance schedules should be developed to specify inspection of replacement
parts that have a specified lifetime. The vendor specified lifetime is 25,000 operations or 10
years from the date of manufacture, whichever occurs first, which was exceeded for a Unit 2
RHR control relay that failed in October 2017 and was over 37 years old.
Additional Tracking Items
None.
2
PLANT STATUS
Unit 2 began the inspection period in end-of-cycle coastdown. On October 16 and 17, 2022, the
unit was down powered and then shutdown for a planned refueling outage (RFO). After
completing the refueling, the unit was restarted on October 29, 2022, synchronized to the grid
on October 30, 2022, and returned to rated thermal power (RTP) on October 31, 2022. On
November 2, 2022, the unit was down powered to 55 percent for a control rod pattern
adjustment and returned to RTP the following day. The unit remained at or near RTP for the
remainder of the inspection period.
Unit 3 began the inspection period at RTP. On November 18, 2022, the unit was down powered
to 58 percent for a control rod sequence exchange, scram time testing, main turbine valve
exercising and testing, and waterbox cleaning. The unit was returned to RTP the following day
and remained at or near RTP for the remainder of the inspection period.
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 performed activities described in IMC 2515,
Appendix D, Plant Status, observed risk significant activities, and completed on-site portions of
IPs. 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
71111.01 - Adverse Weather Protection
Impending Severe Weather Sample (IP Section 03.02) (1 Sample)
(1) Unit common, the inspectors evaluated the adequacy of the overall preparations to
protect risk-significant systems from impending severe weather during winter weather
advisory on December 15, 2022
External Flooding Sample (IP Section 03.03) (1 Sample)
(1) The inspectors evaluated that flood protection barriers, mitigation plans, procedures,
and equipment are consistent with the licensees design requirements and risk
analysis assumptions for coping with external flooding on November 17, 2022
71111.04 - Equipment Alignment
Partial Walkdown Sample (IP Section 03.01) (3 Samples)
The inspectors evaluated system configurations during partial walkdowns of the following
systems/trains:
3
(1) Unit 3, standby liquid control on November 9, 2022
(2) Unit 2, 'A' and 'C' high-pressure service water (HPSW) on December 5, 2022
(3) Unit 3, spent fuel pool cooling system on December 21, 2022
Complete Walkdown Sample (IP Section 03.02) (1 Sample)
(1) Unit common, standby gas treatment system on November 23, 2022
71111.05 - Fire Protection
Fire Area Walkdown and Inspection Sample (IP Section 03.01) (4 Samples)
The inspectors evaluated the implementation of the fire protection program by conducting a
walkdown and performing a review to verify program compliance, equipment functionality,
material condition, and operational readiness of the following fire areas:
(1) Unit 2, reactor building drywell area, elevation 135', PF-24 on October 25, 2022
(2) Unit common, cable spreading and computer rooms, PF-78H, on November 7, 2022
(3) Unit 3, reactor building general area, elevation 165, PF-13J, on December 27, 2022
(4) Unit 3, reactor building high-pressure coolant injection (HPCI) room, PF-62, on
December 28, 2022
71111.06 - Flood Protection Measures
Inspection Activities - Internal Flooding (IP Section 03.01) (2 Samples)
The inspectors evaluated internal flooding mitigation protections in the:
(1) Unit 2, reactor building HPCI room on November 21, 2022
(2) Unit common, 'E-2' emergency diesel generator (EDG) room on December 22, 2022
71111.07T - Heat Exchanger/Sink Performance
Heat Exchanger (Service Water Cooled) (IP Section 03.02) (2 Samples)
The inspectors evaluated heat exchanger performance on the following:
(1) RHR heat exchanger 3AE024 cooled by HPSW
(2) EDG heat exchangers (air, lube oil, and jacket water) cooled by emergency service
water (ESW)
Ultimate Heat Sink (IP Section 03.04) (1 Sample)
The inspectors evaluated the ultimate heat sink performance on the following:
(1) Unit 2 service water, ESW, and HPSW system operation. IP 71111.07T, Sections
02.02.d.4, d.5, d.6 and d.7 were evaluated
4
71111.08G - Inservice Inspection Activities (BWR)
BWR Inservice Inspection Activities Sample - Nondestructive Examination and Welding
Activities (IP Section 03.01) (1 Sample)
(1) The inspectors verified that the reactor coolant system boundary, reactor vessel
internals, risk-significant piping system boundaries, and containment boundary are
appropriately monitored for degradation and that repairs and replacements were
appropriately fabricated, examined, and accepted by reviewing the following activities
from October 18, 2022 to October 25, 2022:
03.01.a - Nondestructive Examination and Welding Activities
- Record review of manual ultrasonic testing of the reactor water clean-up
system pipe to elbow weld, 12-4-5 (NDE Report P2R24-UT-016)
- Record review of manual phased array ultrasonic testing of the core spray
safe end to N5B nozzle dissimilar metal weld 14-B-27 (GE Report 172976)
- Direct observation of manual testing of the core spray N-5B nozzle pipe to
safe end weld 14-B-41 (NDE Report P2R24-UT-005)
- Record review of manual ultrasonic testing of the control rod drive N-9 nozzle
to cap dissimilar metal weld 3-I-19R (NDE Report P2R24-UT-010)
- Record review of encoded phased array ultrasonic testing of the 2-inch level
instrumentation nozzle N16A (GE Report 129135)
- Direct observation of general visual examinations of the moisture barrier (NDE
Reports P2-VT-016 and P2-VT-032)
- Welding activities associated with the permanent installation of the 6-inch
torus drain modification and 2-inch instrument piping located, under work
order (WO) 05209091. This included record review of radiography testing of
16 shop welds (W2 through W10 and W13 through W18) and liquid penetrant
and magnetic particle testing of field weld W33
- Record review of visual test results of torus internal wetted surfaces (WO 05042561)
71111.11Q - Licensed Operator Requalification Program and Licensed Operator Performance
Licensed Operator Performance in the Actual Plant/Main Control Room (IP Section 03.01)
(1 Sample)
(1) The inspectors observed and evaluated licensed operator performance in the control
room during the planned Unit 2 shutdown for refueling on October 16 and 17, 2022,
and the subsequent startup on October 29, 2022
Licensed Operator Requalification Training/Examinations (IP Section 03.02) (1 Sample)
(1) The inspectors observed and evaluated licensed operator requalification training in
the simulator on November 14, 2022
5
71111.13 - Maintenance Risk Assessments and Emergent Work Control
Risk Assessment and Management Sample (IP Section 03.01) (2 Samples)
The inspectors evaluated the accuracy and completeness of risk assessments for the
following planned and emergent work activities to ensure configuration changes and
appropriate work controls were addressed:
(1) Unit 2, HPSW unavailable for intake bay cleaning on October 20, 2022
(2) Unit 2, RFO activities, including '2B' 125 Vdc station battery and 'E-42'
4 kV bus testing and maintenance, on October 25, 2022
71111.15 - Operability Determinations and Functionality Assessments
Operability Determination or Functionality Assessment (IP Section 03.01) (3 Samples)
The inspectors evaluated the licensee's justifications and actions associated with the
following operability determinations and functionality assessments:
(1) Unit 2, refueling water storage tank manual drain valve was difficult to operate on
October 18, 2022
(2) Unit common, 'E-124' transformer circuit breaker 2-54-1505 failed to close after the
'E-12' bus was reenergized on October 23, 2022
(3) Unit 2, 'A' core spray loop minimum flow valve did not indicate full open on
November 17, 2022
71111.18 - Plant Modifications
Temporary Modifications and/or Permanent Modifications (IP Section 03.01 and/or 03.02)
(2 Samples)
The inspectors evaluated the following temporary or permanent modifications:
(1) Unit 2, modification accepting damaged threads as-is without repair on main steam
isolation valve (MSIV) '86C' on November 10, 2022
(2) Unit 2, 'B' and 'D' HPSW pump pressure reduction modification on
December 15, 2022
71111.19 - Post-Maintenance Testing
Post-Maintenance Test Sample (IP Section 03.01) (5 Samples)
The inspectors evaluated the following post-maintenance testing activities to verify system
operability and/or functionality:
(1) Unit 2, reactor core isolation cooling (RCIC) low steam pressure flow rate testing
following maintenance on October 26, 2022
(2) Unit 2, reactor protection system (RPS) motor-generated set voltage regulator and
relay replacements on October 27, 2022
(3) Unit 2, exercising of control rods following maintenance during P2R24 RFO on
October 29, 2022
6
(4) Unit 2, 'B' RHR pump discharge check valve packing replacement on
December 13, 2022
(5) Unit 2, 'B' and 'D' HPSW pump modification acceptance testing following pressure
reduction modification on December 19, 2022
71111.20 - Refueling and Other Outage Activities
Refueling/Other Outage Sample (IP Section 03.01) (1 Sample)
(1) The inspectors evaluated Unit 2 RFO P2R24 activities from October 16 to
October 30, 2022
71111.22 - Surveillance Testing
The inspectors evaluated the following surveillance testing activities to verify system operability
and/or functionality:
Surveillance Tests (other) (IP Section 03.01) (3 Samples)
(1) Unit 2, 'E-12' 4 kV bus loss of offsite power and loss of coolant accident functional
test on October 24, 2022
(2) Unit 2, alternate rod insertion and recirculation pump trip logic system functional test
including scram air header venting and recirculation adjustable speed drive circuit
breaker trips, on October 27, 2022
(3) Unit common, 'E-3' EDG fast start and full load test on November 15, 2022
Containment Isolation Valve Testing (IP Section 03.01) (1 Sample)
(1) Unit 2, 'A' loop MSIV local leak rate test on October 19, 2022
RADIATION SAFETY
71124.01 - Radiological Hazard Assessment and Exposure Controls
Radiological Hazard Assessment (IP Section 03.01) (1 Sample)
(1) The inspectors evaluated how the licensee identifies the magnitude and extent of
radiation levels and the concentrations and quantities of radioactive materials and
how the licensee assesses radiological hazards
Instructions to Workers (IP Section 03.02) (1 Sample)
(1) The inspectors evaluated how the licensee instructs workers on plant-related
radiological hazards and the radiation protection requirements intended to protect
workers from those hazards
Contamination and Radioactive Material Control (IP Section 03.03) (2 Samples)
The inspectors observed/evaluated the following licensee processes for monitoring and
controlling contamination and radioactive material:
7
(1) Workers exiting the radiological controlled area during a RFO
(2) Workers exiting the Unit 2 drywell
Radiological Hazards Control and Work Coverage (IP Section 03.04) (4 Samples)
The inspectors evaluated the licensee's control of radiological hazards for the following
radiological work:
(1) Unit 2, feed water pipe machining inside drywell
(2) Torus dive for filter inspection and desludging
(3) Unit 2, 'B' reactor water cleanup pump replacement
(4) Unit 2, cavity drain down and decontamination
High Radiation Area and Very High Radiation Area Controls (IP Section 03.05) (3 Samples)
The inspectors evaluated licensee controls of the following High Radiation Areas and Very
(1) Unit 2 drywell
(2) Locked High Radiation Area key lock box and log book
(3) Unit 2 torus entrance hatch
Radiation Worker Performance and Radiation Protection Technician Proficiency (IP Section
03.06) (1 Sample)
(1) The inspectors evaluated radiation worker and radiation protection technician
performance as it pertains to radiation protection requirements
OTHER ACTIVITIES - BASELINE
71151 - Performance Indicator Verification
The inspectors verified Constellations performance indicator submittals listed below for the
period October 1, 2021, through September 30, 2022:
MS05: Safety System Functional Failures (SSFFs) Sample (IP Section 02.04) (2 Samples)
(1) Unit 2 SSFFs
(2) Unit 3 SSFFs
MS06: Emergency AC Power Systems (IP Section 02.05) (2 Samples)
(1) Unit 2 Emergency AC Power Systems
(2) Unit 3 Emergency AC Power Systems
OR01: Occupational Exposure Control Effectiveness Sample (IP Section 02.15) (1 Sample)
(1) November 5, 2021, through October 24, 2022
8
PR01: Radiological Effluent Technical Specifications/Offsite Dose Calculation Manual
Radiological Effluent Occurrences (RETS/ODCM) Radiological Effluent Occurrences Sample
(IP Section 02.16) (1 Sample)
(1) November 5, 2021, through October 24, 2022
71152A - Annual Follow-up Problem Identification and Resolution
Annual Follow-up of Selected Issues (Section 03.03) (2 Samples)
The inspectors reviewed the licensees implementation of its corrective action program
(CAP) related to the following issues:
(1) Unit 2 safety relief valve (SRV)-71K nitrogen supply hoses fretting
(2) Unit 2 and Unit 3 Agastat relays for the RHR system, issue report (IR) 4059704 from
October 5, 2017
71152S - Semiannual Trend Problem Identification and Resolution
Semiannual Trend Review (Section 03.02) (1 Sample)
(1) The inspectors reviewed the licensees CAP for potential adverse trends in the third
and fourth quarters of 2022 that might be indicative of a more significant safety issue
INSPECTION RESULTS
Failure to Implement an Effective Maintenance Strategy for Unit 2 and Unit 3 RHR System
Agastat Relays
Cornerstone Significance Cross-Cutting Report
Aspect Section
Mitigating Green None (NPP) 71152A
Systems NCV 05000277,05000278/2022004-01
Open/Closed
The inspectors identified a Green finding and associated NCV of TS 5.4.1.a, "Procedures,"
and RG 1.33, for Constellation's failure to establish an effective maintenance strategy for
Agastat control relays in the safety-related RHR system at both Peach Bottom Unit 2 and
Peach Bottom Unit 3. RG 1.33, Appendix A, November 1972,Section I, requires in part, that
preventive maintenance schedules should be developed to specify inspection of replacement
parts that have a specified lifetime. The vendor specified lifetime is 25,000 operations or 10
years from the date of manufacture, whichever occurs first, which was exceeded for a Unit 2
RHR control relay that failed in October 2017 and was over 37 years old.
Description: On October 5, 2017, TS surveillance procedure ST-O-010-301-2, "A RHR Loop
Pump, Valve, Flow, and Unit Cooler Functional and Inservice Test," for Unit 2 was aborted
due to failure of the 2A RHR pump minimum flow valve, MO-2-10-016A, to operate
automatically at two different steps in the surveillance procedure. Operator action was taken
to manually open MO-2-10-016A following start of the '2A' RHR pump in step 6.4.9 to prevent
damage to the pump from overheating. MO-2-10-016A is a normally closed motor operated
valve credited with an active safety function to open upon start of the '2A' RHR pump, to
protect the pump when operating in low flow or shutoff head conditions, due to a reactor
pressure that is higher than the shutoff head of the pump. MO-2-10-016A must be capable of
9
opening after a 10 second time delay, when the pump breaker is closed, and high differential
pressure exists across the pump. This design feature assures the RHR pump will not operate
at a flow rate less than the minimum flow required for adequate pump cooling. TS 3.3.5.1,
"Emergency Core Cooling System (ECCS) - Instrumentation," Condition E.2 was entered on
October 5, 2017, for inoperable control logic associated with the '2A' RHR pump differential
pressure indicating switch, which controls the opening and closing of MO-2-10-016A, with an
action statement to restore the channel operable status in 7 days.
The direct cause for the failure of the minimum flow valve to open automatically when
required was determined to be the failure of the time delay relay 2-10-K84A. The K84A time
delay relay is a normally de-energized 125 VDC Agastat control relay. At the time of failure,
the K84A relay was determined to be 37 years old, as indicated by a calibration sticker on the
relay. This failure was classified as a Maintenance Rule Function Failure for loss of
equipment needed to support the RHR Low Pressure Coolant Injection function of the RHR
system, monitored at the single train level. The relay was replaced, TS 3.3.5.1, "ECCS -
Instrumentation," Condition E.2 was exited, and the system was returned to service on
October 9, 2017.
An extent of condition investigation conducted in IR 4059704 in November 2017 determined
that there were 12 time-delay relays of the same model as the K84A relay installed in the
RHR system on Unit 2 and Unit 3. The investigation also concluded that the relays were all
classified as non-critical components, in which the Performance Centered Maintenance
(PCM) template recommended no periodic replacement or preventive maintenance for these
relays, and that this was a correct classification. In October 2022, the inspectors determined
that 38 Agastat control relays on Unit 2 had no preventive maintenance schedule, or
replacement frequency specified. The Unit 3 RHR system also had 38 Agastat control relays
with no preventive maintenance schedule, or replacement frequency specified. This
maintenance strategy was adopted on April 20, 2017, before the RHR system relay failed in
October 2017 and is currently the maintenance strategy that is still in place for normally de-
energized Agastat control relays in the RHR system at both Unit 2 and Unit 3.
Constellation procedure ER-AA-200, Preventive Maintenance Program, Revision 6,
Attachment 5 provides guidance for developing a maintenance strategy for non-critical
components. Item 3 lists bullets for determining a reasonable change out frequency based on
the expected service life of a component. Item 3.c states in part, to understand the
consequence of failure, beyond that based on component classification. Item 3.e states in
part, to consider actual operating history of a specific sub-component. Item 3.f states to
consider industry experience with the component. Item 11 states in part, that preventive
maintenance tasks as recommended by PCM templates, do not supersede preventive
maintenance tasks defined by a regulatory required program, such as TSs, and until a
regulatory requirement is changed, the regulatory requirement takes precedence.
The vendor specified a qualified life of these relays of 25,000 electrical operations or 10 years
from the date of manufacture, whichever occurs first.
The inspectors reviewed internal and external operating experience to determine if similar
failed relays examples existed. IR 4228359 documents a case where relay 2-2E-K004 failed
during TS Surveillance S12K-1G-TDR-A1C2 for the Peach Bottom Unit 2 automatic
depressurization system logic system on March 11, 2019. This failure led to an unplanned
entry in TS 3.3.5.1, function 4c until the relay could be replaced. This relay was a TR model
Agastat relay that was normally de-energized and in service for 39 years, similar to the 2-10-
10
K84A relay failure in the Unit 2 RHR system in October of 2017. In their evaluation,
Constellation determined that the cause of the failure was "due to age-related degradation ...
Engineering evaluation A0038908 defines an expected service life of 40 years." In addition,
the failure was "consistent with findings documented in EACE 1422221 [Peach Bottom
evaluation in November 2012] ... Age-sensitive parts include the time delay potentiometer,
solder joins, and on-board capacitors." Based on this failure, Constellation developed actions
to replace 3 similar relays but did not address the relays in the RHR system. These operating
experience examples were not fully considered in the development of a maintenance strategy
for Agastat control relays in the RHR systems at Peach Bottom.
The Constellation maintenance strategy, as shown in the PCM template, was documented as
not required. It did not have a maintenance schedule, nor have a clear development of a
basis using the criteria shown in ER-AA-200 for use of industry experience, failure history,
and vendor information. There was additional opportunity to re-evaluate the strategy following
the failure in 2017. However, no failure analysis was performed on failed time delay relay 2-
10-K84A in the RHR system in 2017, therefore, information was not available to support the
guidance in ER-AA-200, Attachment 5, Item 3.
Corrective Actions: Constellation issued IR 4531974, to review procedure ER-AA-200-1001,
Equipment Classification, to determine if enhancements could be made to this corporate
procedure to ensure the procedure is in compliance with the Peach Bottom licensing basis.
Constellation issued IR 4536189, to perform a review of relevant operating experience, to
determine if a change to the current RHR system relay maintenance strategy is needed, and
if there are concerns with the service life of other Agastat relays at Peach Bottom.
Corrective Action References: IRs 4059704, 4228359, 4301690, 4531974, 4536189
Performance Assessment:
Performance Deficiency: The inspectors determined that not establishing a preventive
maintenance schedule, or effective maintenance strategy for Unit 2 and Unit 3 RHR system
Agastat control relays in accordance with TS 5.4.1.a, and as implemented in station
procedure ER-AA-200, was a performance deficiency that was reasonably within
Constellation's ability to foresee and correct.
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, Agastat relay failures in the RHR system have the potential to render a
single ECCS instrumentation channel, or single train of the RHR system inoperable per TS,
between quarterly surveillance tests. This performance deficiency is similar to Example 13.a
in NRC IMC 0612, Appendix E, "Examples of Minor Issues," dated January 1, 2021.
Significance: The inspectors assessed the significance of the finding using IMC 0609,
Appendix A, The Significance Determination Process (SDP) for Findings At-Power. The
inspectors utilized IMC 0609, Appendix A, Exhibit 2, "Mitigating System Screening
Questions," and answered "No" to Question 1: "If the finding is a deficiency affecting the
design or qualification of a mitigating SSC, does the SSC maintain its operability, or PRA
functionality?". The inspectors answered "No" to Question 2: "Does the degraded condition
represent a loss of the PRA function of a single train TS system for greater than its TS
allowed outage time?". The inspectors answered Yes to Question 3: Does the degraded
condition represent a loss of PRA function of one train of a multi-train TS system for greater
than its TS allowed outage time?
11
Specifically, TSs related to the RHR system had a 7-day allowed outage time (AOT) in 2017,
when the failure of the Agastat relay for '2A' RHR pump occurred. The last time operability of
the 'A' train of the RHR system was confirmed, was during performance of ST-O-010-301-2,
92 days before the October 5, 2017, surveillance. Therefore, past operability during this 92-
day period was unknown and undetermined, which is greater than the TS AOT of 7 days.
Therefore, in accordance with IMC 0609, Appendix A, a detailed risk evaluation (DRE) was
performed.
The Senior Reactor Analyst (SRA) used the Systems Analysis Programs for Hands-On
Evaluation (SAPHIRE), Revision 8.2.6, Peach Bottom Standardized Plant Analysis Risk
Model, version 8.80 to perform the DRE. The basic event, RHR-MOV-CC-F016A, MINFLOW
Valve 10-16A Fails to Open, was set to TRUE. This was performed to invoke a limited
common cause failure potential for the evaluation of the performance deficiency. Other RHR
motor operated valve failure probabilities were increased by an order of magnitude to account
for increased failure probability though current surveillance tests were satisfactory. The SRA
did not include recovery for proper identification and repositioning of the valve(s) by
operators. This is considered a bounding analysis for Unit 2 and would represent the potential
risk to Unit 3, separately. No failures were identified on Unit 3.
A 92-day exposure time was used to bound the degraded condition and performance
deficiency. The increase in core damage frequency (CDF) for the conditional increased failure
to open was calculated to be 9E-8/year for the internal risk contribution. The dominant core
damage sequence consisted of a postulated loss of 4kV E12 bus, containment failure with
loss of all injection, failure to recover the power conversion system, and common failure of
the RHR min flow lines. IMC 0609, Appendix A, "SDP For Findings At-Power," does not
require a detailed evaluation of external risk contribution for internal event CDF increases
below a 1E-7/yr threshold. Additionally, the impact on large early release frequency would not
change this risk determination. This issue was determined to be of very low safety
significance (Green) for the calculated increase in CDF/yr due to the degraded condition.
Cross-Cutting Aspect: Not Present Performance. No cross-cutting aspect was assigned to
this finding because the inspectors determined the finding did not reflect present licensee
performance.
Enforcement:
Violation: TS 5.4.1.a requires in part, that written procedures shall be established,
implemented, and maintained covering the applicable procedures recommended in RG 1.33,
Appendix A, November 1972. RG 1.33, Appendix A, November 1972,Section I, requires in
part, that preventive maintenance schedules should be developed to specify inspection of
replacement parts that have a specified lifetime. The vendor specified lifetime is 25,000
operations or 10 years from the date of manufacture, whichever occurs first, which was
exceeded in October of 2017 for failed Unit 2 RHR control relay, that was over 37 years old.
Contrary to the above, since April 20, 2017, the date the current maintenance strategy was
established, Constellation failed to develop a preventive maintenance schedule, or an
effective maintenance strategy for Agastat control relays in the safety-related RHR system, in
Unit 2 and Unit 3, that have a specified life per TS 5.4.1.a. This led to an aborted TS
surveillance test and entry into a 7-day limiting condition for operation action statement, in
October 2017.
12
Enforcement Action: This violation is being treated as a non-cited violation, consistent with
Section 2.3.2 of the Enforcement Policy.
Observation: Maintenance Strategy for Unit 2 and Unit 3 RHR System Agastat 71152A
Relays
The inspectors performed a detailed review of IR 4059704 from October 5, 2017, in which TS
surveillance procedure ST-O-010-301-2, "A RHR Loop Pump, Valve, Flow, and Unit Cooler
Functional and Inservice Test," for Unit 2 was aborted, due to failure of the '2A' RHR pump
minimum flow valve, MO-2-10-016A, to operate automatically at two different steps in the
surveillance procedure. The direct cause for the failure of the minimum flow valve to open
automatically when required, was determined to be the failure of the Agastat time delay relay
2-10-K84A, that was over 37 years old at the time of failure in 2017. The inspectors
interviewed station operators, system engineers, and maintenance engineers concerning the
event in 2017, and the current Constellation maintenance strategy that is in effect for Agastat
control relays. In addition, a meeting was held with Constellation corporate personnel on
Monday, November 7, 2022, to discuss how plant components are classified, using
Constellation corporate procedure, ER-AA-200, "Preventive Maintenance Program," and
potential enhancements that could be made to this procedure. The inspectors reviewed the
PCM strategy for 42 Agastat control relays in the Unit 2 RHR system, and 42 Agastat control
relays for Unit 3 RHR system. The inspectors identified a Finding and Violation of regulatory
requirements related to the Agastat control relay preventive maintenance strategy for the
safety-related RHR system at Units 2 and 3. Details of the Finding and Violation are
described in Inspection Results Section, NCV 05000277,05000278/2022004-01.
Observation: Unit 2 SRV-71K Nitrogen Supply Hose Fretting 71152A
The inspectors reviewed Constellation staff's corrective actions that were performed following
the identification of a leak in the nitrogen supply hoses to the Unit 2 SRV-71K. On May 16,
2021, Constellation staff identified the nitrogen leak was a result of two stainless steel (SS)
braided hoses rubbing and fretting which was caused by system induced vibration and a
failed tubing support clamp. The issue was entered into the CAP (IR 04424199).
On May 18, 2021, Constellation staff replaced the braided hoses and modified the installation
orientation such that the hoses will remain separated even if not restrained by the tube
support clamp. Following repair and testing, Constellation staff declared SRV-71K operable
and it was returned to service. In addition, Constellation staff updated the hose installation
procedure (M-C-700-600, Revision 2), the relief valve replacement procedure (M-001-006,
Revision 16), and the tubing support specification (NE-00008, Revision 2) to incorporate
detailed installation instructions. Lastly, Constellation staff developed a subsequent design
change (EC 636137) to the braided hose configuration and implemented the change by
installing new hoses on October 23, 2022, during the Unit 2 RFO.
The inspectors reviewed the WO for the interim repair that initially replaced the hoses and
returned SRV-71K back to service. The inspectors reviewed the CAP Evaluation and
resulting corrective actions, including the design and procedure changes. Finally, the
inspectors performed a walkdown of SRV-71K and reviewed the WOs for the permanent
repair (WO 05217981) and extent of condition (WO 05212374). The inspectors determined
the Constellation staff actions had identified the deficiencies that caused the SRV-71K
nitrogen leak and corrective actions and extent of condition reviews were adequate.
13
Observation: Semi-annual Trend Review by Evaluating Potential Adverse 71152S
Trends in the Third and Fourth Quarters of 2022
The inspectors conducted a semi-annual trend review by evaluating sample issues that
occurred in the third and fourth quarters of 2022. During the evaluation, the inspectors
verified the issues identified were addressed within the scope of the CAP. The inspectors
reviewed health reports and related databases for trends and considered prior issues while
performing routine walkdowns and attending the plan of the day meetings. The inspectors did
not identify any substantive adverse performance trends or repetitive equipment failures
during this time that were not already identified by Constellation.
The inspectors reviewed potential trends in human performance issues, station
communication challenges, fire-related issues, and equipment degradation. Of these, the
inspectors noted significant plant impacts from river conditions during the summer period.
Unit 2 main condenser fouling caused by river conditions required an abnormal number of
downpowers. In addition, numerous safety-related and non-safety-related river-cooled heat
exchangers in both units required cleaning during the period, some multiple times. The
inspectors reviewed Constellations monitoring of heat exchanger performance and observed
the results of some manual cleanings. The inspectors observed abnormally high amounts of
biological debris (shell remains) and silt but did not observe evidence of live clams within the
systems. Constellation identified and issued trend issue reports for the heat exchanger
fouling and, separately, the Unit 2 main condenser performance. The inspectors determined
that the identification of an adverse trend for consideration of long-term corrective actions to
improve performance was appropriate.
Based on the overall results of the semi-annual trend review, the inspectors determined that
Constellation had identified adverse trends at Peach Bottom Atomic Power Station before
they could become more significant safety problems. The inspectors continue to monitor the
CAP and maintenance effectiveness during routine inspection activities.
EXIT MEETINGS AND DEBRIEFS
The inspectors verified no proprietary information was retained or documented in this report.
- On January 20, 2023, the inspectors presented the integrated inspection results to
Ron DiSabatino, Plant Manager, and other members of the licensee staff.
- On November 10, 2022, the inspectors presented the Unit 2 and Unit 3 RHR system
Agastat relays inspection results to Sarah Ramos, Senior Manager of Strategic
Engineering, and other members of the licensee staff.
- On October 28, 2022, the inspectors presented the exit meeting for IP 71124.01 and
IP 71151 inspection results to Ron DiSabatino, Plant Manager, and other members of
the licensee staff.
- On October 25, 2022, the inspectors presented the Peach Bottom Unit 2 ISI inspection
results to Marcellus Ruff, Manager of Peach Bottom Programs Engineering, and other
members of the licensee staff.
- On October 12, 2022, the inspectors presented the Triennial Heat Sink inspection results
to David A. Henry, Site Vice President, and other members of the licensee staff.
14
DOCUMENTS REVIEWED
Inspection Type Designation Description or Title Revision or
Procedure Date
71111.01 Operability SE-4 Flood - Bases Revision 34
Evaluations
Procedures LS-AA-4 Preparedness for Extreme External Events Revision 0
OP-AA-108-111- Severe Weather and Natural Disaster Guidelines Revision 24
1001
OP-PB-108-111- Preparation for Severe Weather Revision 19
1001
SE-4 Flood - Procedure Revision 43
SY-AA-101-146 Severe Weather Preparation and Response Revision 3
71111.04 Corrective Action Condition Reports
Documents IR 04087639
Miscellaneous M-363 P & I Diagram Fuel Pool Cooling & Clean-Up Revision 44
Procedures M-315 P & I Diagram Emergency Service Water and HPSW Syss Revision 94
M-397 Standby Gas Treatment Control Diagram Revision 61
SO 19.8.A-3 Fuel Pool Cooling System Routine Inspection Revision 13
SO 9A.8.A Standby Gas Treatment System Routine Running Inspection Revision 6
SO 9A.8.B Standby Gas Treatment System Routine Shutdown Revision 3
Inspection
ST-O-011-350-5 SBLC Explosive Valve Charge Continuity Check and Valve Revision 2
Position Verification
ST-O-032-350-2 HPSW Valve Alignment Verification Revision 4
71111.05 Miscellaneous ECR 632254 PF-0007 REV 4AY- Cable Spread Room Revision 0
Procedures PD-12 Typical Penetration Seal Detail Protective Topping for Foam Revision 0
Seals (SF-60)
PD-5 Typical Penetration Seal Detail External Pipe or Conduit Revision 1
Seal (SF-20)
15
Inspection Type Designation Description or Title Revision or
Procedure Date
PF-0007 Combustible Loading Analysis Revision 5C
PF-13J, Unit 3 Procedures Revision 3
RX Building: Unit 3 RX Building, General Area - Elevation 165-0
General Area -
Elevation 165-0,
Revision 3
PF-24 Unit 2 Reactor Building, Drywell Area - Elevation 135'-0" Revision 6
PF-62 Unit 3 RX Building; HPCI Room - Elevation 88-0 Revision 7
PF-78H Turbine Building Common, Cable Spreading and Computer Revision 9
Rooms - Elevation 150-0
Work Orders C0259205 DEHC PENE TBC-15-302-2-6015/6015A ECR 14-00421 Revision 0
71111.06 Corrective Action IR 04415793 E2 Roof/roll-up door area leaks during rainfall
Documents
Miscellaneous ECCS Flooding
Analysis
Procedures M-518 Plumbing, Drainage Reactor Building Unit No. 2 Plan at El Revision 12
71111.07T Engineering PM-0589 RHR Heat Exchanger Performance Evaluation Revision 7
Evaluations
Miscellaneous Peach Bottom Atomic Power Station, Unit 2 and 3 Response Date
to NRC Generic Letter 89-13, "Service Water System 01/29/1990
Problems Affecting Safety-Related Equipment"
ER-PB-450-1006- Structures Monitoring Inspection Checklist - Pump Structure Performed
F-0 Rooms 800, 801, 802, 803, 804, 805-807 6/17/2022
Work Orders 04268137-14 Eddy Current Inspection Report - A RHR Heat Exchanger Performed
(3AE024) 04/20/2021
04869085 01 performed
10/23/20
04988982 01 performed
10/29/21
RT-0-033-600-2 Flow Test of ESW to ECCS Coolers and Diesel Generator Performed
Coolers 8/27/22
RT-X-010-661-3 RHR Heat Exchanger Performance Calculation Test Performed
12/01/2021
16
Inspection Type Designation Description or Title Revision or
Procedure Date
71111.08G Corrective Action 04530721
Documents
71111.13 Corrective Action IR 4530982
Documents
Procedures SO32.7.A-2 Placing Unit 2 HPSW Loops In-Service Using Unit 3 HPSW Revision 16
Pumps
71111.15 Corrective Action 4530585
Documents 4531583
Procedures ST-O-014-301-2 Core Spray Loop 'A' Pump, Valve, Flow and Cooler Revision 45
Functional and Inservice Test
ST-O-054-751-2 E-12 4kV Undervoltage Relays and LOCA Loop Functional Revision 27
Test
Work Orders WO 05084304
71111.18 Corrective Action CRs
Documents IR 04531434
Miscellaneous EC637808 AO-2-01A-086C Bonnet Stud Hole Threads Damaged Revision 0
ASME B1.1-2003 Unified Inch Screw Threads Reaffirmed
2008
EPRI TR- Bolted Joint Maintenance & Applications Guide December
104213s 1995
NMP Design NCR LIM MSIV BOLTHOLE AS-IS, The Final NCR
report certification Disposition is Use-As-Is MSIV Drawing
SR 534 Technical Justification for the Acceptance of the Damaged Revision 1
Bonnet Studs of 2MSS*AOV6A, 6B, 6C, 6D, 7A, 7B, 7C, &
7D
Work Orders 04269685
04892413
04892415
71111.19 Corrective Action IR 04532568,
Documents IR 04532960
17
Inspection Type Designation Description or Title Revision or
Procedure Date
Miscellaneous EC 627497
Procedures GP-11.E RPS SCRAM and ARI Reset Revision 26
GP-8.C Groups I, II, and II Inboard Half Isolation Revision 22
SO60F.6.A-2 Transferring Reactor Protection System Power Supplies Revision 19
ST-O-003-561-2 Control Rod Exercise - All Rod Revision 20
ST-O-010-306-2 B RHR Loop Pump, Valve, Flow and Unit Cooler Functional Revision 57
and Inservice Test
ST-O-013-210-2 RCIC Low Steam Pressure Flow Rate Test Using Auxiliary Revision 5
Steam
Work Orders 04892413
04892415
05285285
05312953
71111.20 Operability M-004-400 Revision 51
Evaluations
Procedures GP-2-2 Normal Plant Start-Up Revision 27
GP-3-2 Normal Plant Shutdown Revision 27
GP-6 Refueling Operation Revision 41
71111.22 Corrective Action IR 4532631
Documents
Miscellaneous TCC 22-0034 ST-I-03B-105-2 Revision 16A
Procedures ST-I-03B-105-2 ARI/RPT Logic System Functional Test with Scram Air Revision 16
Header Venting and Recirc Breaker Trips
ST-O-052-413-2 E-3 Diesel Generator Fast Start and Full Load Test Revision 26
ST-O-054-751-2 'E-12' 4kV Bus Undervoltage Relays and LOCA Loop Revision 27
Functional Test
ST/LLRT MSIV LLRT Test Revision 20
20.01A.02
Work Orders 5106406
71152A Corrective Action 04424884
Documents 4059704 MO-2-10-16A Not Opening on RHR Pump Start 10/05/2017
4219191 E434 LC Failed to Energize During a 4kV Bus Fast Transfer 02/11/2019
18
Inspection Type Designation Description or Title Revision or
Procedure Date
4301690 Relay PCM Template Change 12/05/2019
4393997 Found Relay 3-10A-K70A out of tolerance high 01/05/2021
Corrective Action 4531974 NRC ID: Component Classification IAW ER-AA-200-1001 10/25/2022
Documents 4536189 Agastat Relay PM Strategy Challenged 11/10/2022
Resulting from
Inspection
Miscellaneous Catalog 5- TE Connectivity, "Agastat E7000 Series, Nuclear Qualified Revised 3-13
1773450-5 Time Delay Relays"
Constellation Relays - Control / Timing Revision 1
Maintenance
Template
Constellation Relays - Control / Timing Revision 2
Maintenance
Template
ICES 424948 Exelon Maintenance Rule - Failure Classification Form, 11/17/2017
Peach Bottom Unit 2
Procedures ER-AA-200 Preventive Maintenance Program Revision 6
ER-AA-200-1001 Equipment Classification Revision 6
PI-AA-125-1003 Corrective Action Program Evaluation Manual Rev. 7
ST-I-010-100-2 RHR Loop A Logic System Functional Test 05/01/2018
ST-I-010-100-2 RHR Loop A Logic System Functional Test 12/02/2015
ST-O-010-301-2 "A" RHR Loop Pump, Valve, Flow, and Unit Cooler 10/05/2017
Functional and Inservice Test
ST-O-010-301-2 "A" RHR Loop Pump, Valve, Flow and Unit Cooler 05/17/2022
Functional and Inservice Test
Work Orders WO 05153522 SV-2-16-071K (RV-2-16-071K): Replace Hoses 05/18/2021
71152S Corrective Action Issue Report s
Documents (IRs)
4511479
4515678
4516673
4516882
4516882
4516918
19
Inspection Type Designation Description or Title Revision or
Procedure Date
4516918
4517287
4517287
4517290
4517290
4517290
4517998
4518779
4518811
4519330
4519951
4520173
4520180
4520301
4520301
4520301
4520488
4520991
4521141
4521519
4522738
4522745
4524364
4524476
4524658
4525857
4526146
4526147
4526154
20