ML24229A104
| ML24229A104 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 09/25/2024 |
| From: | Geoffrey Miller NRC/RGN-IV/DORS |
| To: | Sullivan J Entergy Operations |
| References | |
| EA-24-030, IR 2023004 | |
| Download: ML24229A104 (1) | |
See also: IR 05000382/2023004
Text
September 25, 2024
Joseph Sullivan, Site Vice President
Entergy Operations, Inc.
17265 River Road
Killona, LA 70057
SUBJECT: WATERFORD STEAM ELECTRIC STATION, UNIT 3 - INTEGRATED
INSPECTION REPORT 05000382/2023004, DISPUTED NON-CITED
VIOLATION REVISED
Dear Joseph Sullivan:
On February 12, 2024, the U.S. Nuclear Regulatory Commission (NRC) issued the subject
inspection report, Agencywide Documents Access and Management System (ADAMS)
Accession No. ML24039A199. The inspection report documented a non-cited violation (NCV)
for the failure to maintain mitigation strategies for beyond-design basis external events as a
result of the failure to ensure that the starting batteries had sufficient capacity for the FLEX
(Diverse and Flexible Mitigation Capability) N and N+1 diesel generators to perform their
required functions, NCV 05000382/2023004-03.
In a letter dated March 11, 2024 (ML24071A185), you provided your written response and
contested NCV 05000382/2023004-03. On March 15, 2024 (ML24074A374), the NRC
acknowledged receipt of your letter.
The NRC conducted a detailed review of your March 11, 2024, letter and examined
circumstances and applicable regulatory requirements in accordance with Part I, Section 2.8 of
the NRC Enforcement Manual. The review included staff who were not involved in the original
inspection effort. The details of the NRCs evaluation are contained in the enclosure.
After consideration of the basis for your dispute of the NCV, the NRC concluded that the original
NCV remained valid. However, the staff revised the NCV to enhance its clarity and modified the
dates of noncompliance. The revised language for the NCV is provided in the enclosure. The
NRC will reissue Inspection Report 05000382/2023004 to document the revised NCV.
In addition, during the review of the issue, the NRC determined that the performance deficiency
needed enhancement. The revised language for the performance deficiency is provided in the
enclosure. The NRC also determined that when evaluating the significance of the finding, a
detailed risk evaluation was required. A Senior Reactor Analyst performed the detailed risk
evaluation and determined the overall risk significance of the finding was of very low safety
significance (Green). The revised language of the performance deficiency and the detailed risk
evaluation will also be included in the reissued inspection report.
J. Sullivan 2
In accordance with 10 CFR 2.390 of the NRCs Agency Rules of Practice and Procedure, a
copy of this letter and its enclosure will be made available electronically for public inspection in
the NRC Public Document Room and from the NRCs ADAMS, accessible from the NRC
website at http://www.nrc.gov/reading-rm/adams.html.
Should you have any questions concerning this letter, please contact John Dixon of my staff
at 817-200-1574.
Sincerely,
Geoffrey B. Miller, Director
Division of Operating Reactor Safety
Docket No. 05000382
License No. NPF-38
Enclosure:
NRC Evaluation of Licensee Response
to an NCV
Signed by Miller, Geoffrey
on 09/25/24
SUNSI Review: ADAMS: Non-Publicly Available Non-Sensitive Keyword:
By: JGK Yes No Publicly Available Sensitive NRC-002
OFFICE SES:ACES RI:DORS:EB2 TL:ACES C:DORS:PBD C:DORS:EB2
NAME JKramer ASaunders BAlferink JDixon NTaylor
SIGNATURE /RA/ E /RA/ E /RA/ E /RA/ E /RA/ E
DATE 08/20/24 08/19/24 08/19/24 08/16/24 08/19/24
NAME DCylkowski DJones KGamin GMiller
SIGNATURE /RA/ E /RA/ E /NLO/ E /RA/ E
DATE 08/19/24 09/23/24 09/25/24 09/25/24
NRC Evaluation of Licensee Response to a Non-cited Violation (NCV)
Background:
On February 12, 2024, the U.S. Nuclear Regulatory Commission (NRC) issued Integrated
Inspection Report 05000382/2023004 that included an NCV of Title 10 of the Code of
Federal Regulations (10 CFR) 50.155(b)(1) (NCV 05000382/2023004-03) to Entergy
Operations, Inc. (Entergy or licensee). In a letter dated March 11, 2024, Entergy denied
NCV 05000382/2023004-03 and provided its position that Waterford Steam Electric Station,
Unit 3 (Waterford) complied with regulatory requirements for ensuring the Diverse and Flexible
Mitigation Capability (FLEX) diesel generators had sufficient capacity to perform their design
function.
The NRC staff performed an independent review of the licensees position as described in its
March 11, 2024, letter. The NRC staff reviewed regulatory requirements in 10 CFR 50.155, the
Waterford Final Integrated Plan (FIP), the Waterford Technical Requirements Manual, battery
vendor manuals, FLEX diesel generator vendor manuals, Electric Power Research Institute
(EPRI) FLEX Operating Experience Bulletins (OEBs)21-001 and 21-002, EPRI Preventative
Maintenance Basis for FLEX (PMBD), Waterford Flood Hazards Mitigation Strategies
Assessment, Regulatory Guide 1.226 Flexible Mitigation Strategies for Beyond-Design-Basis
Events (ML19058A012), Nuclear Energy Institute (NEI) 20-10 Mitigation of Beyond Design
Basis Events Program Description Template, Waterford Staffing Analysis during a FLEX event,
and NRC Inspection Report 05000382/2017009 related to FLEX compliance at Waterford,
including a Notice of Violation, issued on July 20, 2018.
Additionally, the staff interviewed Region IV and Office of Nuclear Reactor Regulation (NRR)
subject matter experts familiar with FLEX equipment requirements and regulations to gain a
valuable perspective on the development and evaluation of Waterfords strategies.
Topical Areas Discussed in Licensees Denial and NRC Evaluation
Topic 1: Operating Experience for FLEX Diesel Starting Battery Failures
The reviewer conducted a search for industry-facing documents related to starting battery
failures that impacted FLEX equipment reliability, including a review of NRC inspection
results.
EPRI OEB 21-001 Starting Batteries / Battery Chargers provided guidance on an
increasing trend in failure of FLEX starting batteries. It also provided a list of best practices
in maintenance and testing of FLEX equipment battery systems, including actions such as
the use of a battery tester to perform diagnostic checks of batteries and guidance for jump
starting machines with dead batteries in station procedures.
EPRI OEB 21-002 FLEX Equipment Functionality Assessments Related to Battery Failure
provided information on what to consider in functionality assessments of supported FLEX
equipment if starting batteries are found in FLEX equipment. The document addressed
whether there is alternate means of starting the supported piece of FLEX equipment and
whether there is sufficient time to perform the recovery actions.
Enclosure
Additionally, the staff noted that there have been several other similar enforcement actions
in recent years, including two nearly identical NCVs:
- South Texas Project NCV 05000498/2021002-02, Failure to Maintain FLEX Equipment
Consistent with NRC Order EA-12-049 for failure to implement a battery replacement
strategy, leading to a FLEX diesel generator failure to start.
- Comanche Peak NCV 05000445/2022001-01, Failure to Maintain FLEX Strategy for
the licensees failure to maintain the starting batteries for the steam generator fill pumps.
The staff noted that Waterford reviewed the South Texas Project FLEX battery failures in
WT-WTHQN-2021-00498-00005 which concluded that the preventative maintenance (PM)
program was adequate, resulting in no corrective actions. The staff determined that this was
a missed opportunity for the licensee to recognize that its maintenance practices were
inadequate and did not meet the guidance in OEB 21-001.
Topic 2: Importance of Batteries in FLEX Diesel Generators
Licensees Contention:
The licensee asserted that batteries are considered FLEX-support equipment and are not
subject to the requirements of the Order EA-12-049 (now codified in 10 CFR 50.155) as
equipment necessary to support the Phase 2 strategies. The licensee further asserted that
the EPRI PMBD for FLEX equipment templates refers to batteries and battery chargers as
supporting equipment, and it is widely recognized that the expectation to maintain the
equipment to meet the FLEX strategies was the intended target of the EPRI FLEX PM
template.
Furthermore, the licensee asserted that since the industry-wide implementation of
NEI 12-06, it has been widely discussed throughout the industry that an occurrence of a
non-start of a FLEX diesel generator due to battery failure does not constitute a failure of
that equipment to perform its function.
NRC Evaluation:
The staff reviewed the NRC-endorsed EPRI PMBD documentation, which clearly details that
diesel generator batteries are an integral component of the FLEX diesel generator. The
document also details the batteries as a common failure cause in diesel engines. The staff
also reviewed the Waterford Steam Electric Station, Unit 3, Final Integrated Plan, revision 1,
dated July 20, 2016. The Final Integrated Plan states at Section 2.19.6 that [m]aintenance
and testing of FLEX equipment is governed by the Entergy Preventive Maintenance (PM)
Program as described in EN-DC-324. The Entergy PM Program is consistent with INPO
AP-913 and utilizes the EPRI Preventive Maintenance Basis Database as an input in
development of fleet specific Entergy PM Basis Templates. The staff reviewed Waterfords
PM basis document for FLEX diesel generators 1000 KW and below, which clearly states
that batteries are considered a component of the FLEX diesel generator, contrary to the
statement provided in the licensees letter. The staff reviewed the online version of the
PMBD and determined that FLEX batteries being detailed solely as FLEX support
equipment was not supported by the online database.
2
Additionally, the staff interviewed several subject matter experts who were involved in the
formative discussions of the FLEX policy documents (including staff from Region IV and
multiple former Japan Lessons Learned Project Directorate staff members in NRR), and
none recalled any conclusion being reached that starting batteries for FLEX equipment
would be treated as FLEX support equipment.
Regarding the failures of the starting batteries, the staff reviewed the FIP and determined
that the primary design function for N and N+1 diesel generator is to provide 480 V AC
power to recharge the safety related DC batteries and provide AC power for various FLEX
equipment. As described in the issued violation, the minimum capacity of the batteries on
the N and N+1 diesels were not ensured. This directly affected the function of the FLEX
diesels to provide AC power in the documented timeline. The staff reviewed EPRI PMBD
and the licensees PM template, both of which include diesel generator starting batteries as
integral components of the diesel. The diesel generator would not be able to perform its
design function without the batteries. As stated below, the staff did not view any of the other
batteries described by the licensee as being available options during a FLEX event, nor did
the staff agree that replacing these batteries with anything other than a like-for-like spare
would be a skill-of-the-craft activity.
Additionally, the licensees contention is not consistent with industry guidance, including
OEB 21-001, which states a failure of a starting battery could impact the capability to
perform a mitigating strategy.
The licensee referenced OEB 21-002 in asserting that a supported piece of FLEX
equipment need not be considered non-functional based on a starting battery failure, if the
following conditions are met for declaring the supported piece of FLEX equipment functional
but degraded:
- An alternate means of starting the supported piece of FLEX equipment is available
(e.g., jumper cables, spare batteries).
- There is sufficient time to perform the recovery actions to start the supported FLEX
equipment within the time allotted.
The NRC staff determined that neither of the conditions in OEB 21-002 would be met if a
flood, tornado, tornado missile, or hurricane impacted the N+1 building such that it was
inaccessible.
The staff found no evidence in the review of the formative FLEX guidance documents to
support the licensees position on FLEX diesel functionality without starting batteries. While
the staff agrees that the function of the diesel generator assembly is to provide AC power,
the diesel engine must be started (providing relative motion to the generator field) and that
action requires functional batteries.
3
Topic 3: Whether Replacing FLEX Diesel Starting Batteries is a Skill of the Craft
Activity
Licensees Contention:
The licensee asserted that with the diverse and flexible solutions offered in the FLEX
procedures, the ability to jump, swap, or replace a battery immediately is within the design of
the FIP for FLEX implementation, is considered skill of the craft, and does not need to be
part of a procedure.
NRC Evaluation:
The staff reviewed the licensees skill of the craft position and determined that the
replacing of a like for like battery is very well within the skill of the craft. However, if the
batteries are of different configurations the following could be affected: connections, cable
length, and starting amperage. The staff reviewed photos provided by the licensee of the
battery configurations on the N, N+1, FLEX water transfer pump (FWTP) and air compressor
diesels. The N and N+1 diesels each use a pair of large 8D type batteries with both
terminals on one end, connected in series to make a 24-volt starting circuit. The reviewer
noted that the cables connecting the batteries appear to have little or no slack. By contrast,
the FWTP and air compressor each have a single 12-volt battery and are smaller batteries
with terminals on either end. Both of these smaller batteries would have to be used to create
the needed 24-volt circuit and would likely require a new cable to be configured in the field
to connect them together.
The staff interviewed the Waterford Emergency Preparedness manager who was a Senior
Reactor Operator (SRO) at Waterford when the strategies were developed, who described
the manner in which Waterford would implement the battery replacement strategy if the
batteries on the N diesel were found dead. The former SRO stated he would immediately
direct the operators to scavenge the batteries from either the FWTP or the station black out
air compressor without first attempting to troubleshoot or to start the N+1 diesel generator
(contrary to the FIP). This misstatement highlights the importance of having written
procedures governing the conduct of FLEX strategies, as valuable time in the FLEX timeline
would be lost in the effort to start the N diesel using a single 12-volt battery.
The staff emphasizes that the need for procedures is extremely important due to operations
making mistakes when a viable path, such as the N+1 diesel, might be present. The staff
also noted that there are no recovery actions within the licensees procedures to restore the
cannibalized batteries for the FWTP and station blackout air compressor which are needed
later in the FLEX timeline. The staff also noted that OEB 21-001 recommends as a best
practice to include instructions for jump starting engines in the equipment operating
procedures, which the licensee has not implemented.
The staff determined that replacing the N or N+1 batteries with the smaller batteries from the
FWTP and air compressor should not be viewed as a skill of the craft activity for the auxiliary
operators. Time spent by auxiliary operators learning how to connect smaller batteries and
building new cables in the field would have an adverse effect on the FLEX timeline, as
discussed later in this evaluation.
4
Topic 4: Spare Battery Availability During a Beyond-Design-Basis External Event
Licensees Contention:
The licensee stated that it is important to note that the FLEX equipment necessary to
mitigate the beyond design basis external event was still functional. The licensee noted that
the inspection report stated that Because there was a set of ready spare batteries that
would be able to be changed out in an actual event, the function of the FLEX AC power
supply was not considered fully lost. All FLEX functions could still be completed within the
time allotted.
NRC Evaluation:
The staff considered this position and noted that the assumptions in the FIP state, in part,
that other equipment, such as portable AC power sources, portable back-up DC power
supplies, spare batteries, and equipment for 10 CFR 50.54(hh)(2), may be used provided it
is reasonably protected from the applicable external hazards and has predetermined
hookup strategies with appropriate procedural guidance and the equipment is stored
in a relative close vicinity of the site [emphasis added]. The staff noted that the licensee
did not have procedures for changing out the batteries, and the N+1 building is only
designed as per ASCE 7-10 Minimum Design Loads for Buildings and Other Structures,
standard and is not designed to withstand all environmental conditions as detailed in the
Updated Safety Analysis Report (flood, extreme winds, hurricane, seismic).
Furthermore, the staff reviewed the previously issued NOV 05000382/2017009-01 which
took exception with the licensees failure to create procedural guidance to protect the N+1
diesel from the effects of postulated events. In order to consider the spare batteries as
available for the strategy, the spare batteries from the N+1 building must also be protected
from these events. Therefore, the staff was not able to credit this position.
Topic 5: Maintenance of the Flex Diesel Batteries
Licensees Contention:
The licensee asserted the diesel generators are appropriately tested and maintained to
ensure their function.
NRC Evaluation
OEB 21-001 was specifically issued to address inadequate maintenance practices on FLEX
batteries. It states, in part, that FLEX equipment starting batteries and battery charger
related events have been the most common equipment operating experience (OE) entries
shared in the EPRI FLEX Equipment Maintenance Event Collaboration Site. The document
specifically calls out capacity of the batteries as a concern that should result in regular
capacity testing. In addition, OEB 21-001 referenced EPRI 3002012818, Insights from the
FLEX Preventative Working Group which provided additional guidance for the storage,
maintenance and periodic replacement of FLEX batteries.
5
On April 18, 2023, the licensee performed maintenance work orders on the FLEX N and
FLEX N+1 diesel generators. These inspections included ensuring that the supporting
batteries for the FLEX equipment had clean tops, tight connections and measured the
output voltage on the connected battery charger as a measure of battery health. The
licensee stated it is appropriate to consider these work orders to be failure detection
activities. Both diesels were found in a failed state a month later despite the licensees
satisfactory completion of these failure detection activities. The licensee PM process failed
to identify that the batteries on the N FLEX diesel did not have the required starting capacity.
The staff noted that the licensees practice of measuring terminal voltage on the battery with
the charger connected provides no information about the state of charge or capacity of the
battery, contrary to the recommendations of OEB 21-001. The inadequacy of this approach
was demonstrated by the failure of the N diesel in May 2023, which had adequate terminal
voltage until the operators attempted to start the diesel and the battery voltage dropped
immediately.
The staff reviewed testing of the diesel generator batteries and found that the licensee was
not performing battery capacity testing to ensure the minimum capacity was maintained for
the batteries. The staff noted that in the issued report, the resident inspectors included an
observation of multiple failures of other batteries in different systems onsite, suggesting a
larger adverse trend at the station in the way that flooded lead acid batteries are being
maintained.
The maintenance that was performed on the batteries just weeks before did not ensure the
batteries would perform their function of starting the diesel generator. Therefore, the staff
was not able to credit the licensees position that starting batteries on the FLEX diesel
generators were being properly maintained.
Topic 6: Impact of Battery Swaps on the FLEX Timeline
Licensees Contention:
The licensee described that the equipment necessary to perform the required FLEX function
(that of the diesel generator) was not compromised. The ability to start the diesel generator
was degraded, but the functionality of the diesel generator was not in question and met the
required timeline.
NRC Evaluation
The licensees FIP states, in part, that the site has 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to get the FLEX diesel operating
before failure of the safety related batteries. In support of this overall strategy, the licensee
established a timeline of actions for each operator in procedure CIN-2016-00017,
Waterford 3 Steam Electric Station Phase 2 Staffing Assessment, Revision 1. The
following table shows a subset of the time-critical actions required to accomplish this
strategy. Actions that are specifically related to restoring AC power from the N or N+1
diesels are highlighted in green.
6
The reviewer noted that AO#3 is tasked with setting up the FLEX diesel, but a start attempt
of the N diesel does not occur until AO#1 begins that process 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> into the event. AO#1
then has 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> of control room supervisor support time assigned due to the importance of
establishing AC power to the overall strategy. The reviewers assume that the initial starting
attempt for the N diesel occurs at approximately 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> into the event.
Based on the NRCs position in the safety evaluation for FLEX, and as documented in NOV
05000382/2017009-01, the spare equipment outside of the nuclear plant island structure
(NPIS) cannot be credited during a flood, levee failure, tornado missile, localized intense
precipitation, or hurricane (extreme conditions) due to the building/haul path being
inaccessible. The licensees FIP requires that the credited N+1 equipment be moved into the
NPIS prior to foreseeable external events.
The staff determined as per procedure CIN-2016-00017, the N diesel is discovered to be
non-functional approximately 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> into the recovery. The licensee would have to start
troubleshooting the N diesel, determine the problem, or move on to the N+1 diesel which
should be pre-staged for foreseeable external events. In the case of some external events,
the operators would have to move the N+1 diesel to the NPIS at this time. There are no
procedural steps to test the N+1 before moving it to make sure it functions properly. Setting
up the N+1 diesel requires re-entering the procedural attachment (rerouting cables,
realigning 480 VAC circuit breakers, etc.) which is a three-hour activity in the timeline. Once
the operators finish aligning the N+1 diesel and discover that it also has failed starting
batteries, the operators would then be forced to consider other sources of starting power for
either the N or N+1 diesel. The last effort for the licensee is to pull batteries from other FLEX
equipment without written procedures as to which equipment to scavenge, how to hook up
batteries with different terminal configurations, or how to assemble the cables which might
be required to do so. The lack of procedural guidance significantly challenges the remaining
time left in the FIP strategy after the N and N+1 diesels are discovered to be in a failed
state. Furthermore, the licensees FLEX strategies are silent on where the operators would
obtain batteries to restore the function of the FWTP and FLEX air compressor when they are
needed later in the FLEX timeline.
7
Based on a review of the actions that would be required to recover from the failure of the
starting batteries of both the N and N+1 diesels, and the uncertain outcomes and timing of
actions to connect off-schedule batteries from other equipment, the NRC staff concluded
that the licensees strategy to restore AC power to a safety bus within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after a
beyond design basis event was unlikely to be successful.
Revised NCV 05000382/2023004-03 and Revised Performance Deficiency
As a result of the evaluation above, the NRC will revise the NCV to enhance its clarity and
modify the dates of noncompliance to begin with the effective date of 10 CFR 50.155 and end
with the date on which the noncompliance was corrected, and will revise the performance
deficiency as follows:
Revised NCV 05000382/2023004-03
Title 10 CFR 50.155(b)(1), states, in part, strategies and guidelines to mitigate beyond-
design-basis events from natural phenomena must be capable of being implemented site-
wide and must include maintaining or restoring core cooling capabilities.
The licensee established Waterford Steam Electric Station, Unit 3, Final Integrated Plan,
revision 1, dated July 20, 2016, to meet the requirements of NRC Order EA-12-049. This
order was codified and made generically applicable by 10 CFR 50.155, on September 9,
2019 (84 FR 39684). Section 2.19.6, Equipment Maintenance and Testing, of the Final
Integrated Plan describes, in part, the licensees actions for complying with 10 CFR 50.155
for maintenance and testing of the FLEX equipment. This includes maintenance and testing
of the starting batteries for the FLEX N and N+1 diesel generators to ensure sufficient
capacity to perform their required functions.
Contrary to the above, from September 9, 2019, to May 16, 2023, the licensee failed to
maintain mitigation strategies for beyond-design basis external events. Specifically, the
licensee failed to maintain mitigation strategies for beyond-design basis external events
because the preventive maintenance program, section 2.19.6, Equipment Maintenance and
Testing, of the Final Integrated Plan, which describes the licensees actions for complying
with 10 CFR 50.155, failed to ensure that the starting batteries had sufficient capacity for the
FLEX N and N+1 diesel generators to perform their required functions.
Revised Performance Deficiency
The licensee failed to maintain mitigation strategies for beyond-design-basis external events
because the preventive maintenance program, section 2.19.6, Equipment Maintenance and
Testing, of the Final Integrated Plan, which describes the licensees actions for complying
with 10 CFR 50.155, failed to ensure that the starting batteries had sufficient capacity for the
FLEX N and N+1 diesel generators to perform their required functions.
8