ML14043A056
| ML14043A056 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 02/11/2014 |
| From: | Webb Patricia Walker NRC/RGN-IV/DRP/RPB-A |
| To: | Halpin E Pacific Gas & Electric Co |
| References | |
| IR-13-005 | |
| Download: ML14043A056 (42) | |
See also: IR 05000275/2013005
Text
UNITED STATES
NUCLEAR REGULATORY COMMISSION
REGION IV
1600 E. LAMAR BLVD.
ARLINGTON, TX 76011-4511
February 11, 2014
Mr. Edward D. Halpin
Senior Vice President and
Chief Nuclear Officer
Pacific Gas and Electric Company
Diablo Canyon Power Plant
P.O. Box 56, Mail Code 104/6
Avila Beach, CA 93424
SUBJECT:
DIABLO CANYON POWER PLANT - NRC INTEGRATED INSPECTION
REPORT 05000275/2013005 and 05000323/2013005
Dear Mr. Halpin:
On December 31, 2013, the U.S. Nuclear Regulatory Commission (NRC) completed an
inspection at your Diablo Canyon Power Plant. On January 16 and February 7, 2014, the NRC
inspectors discussed the results of this inspection with you and members of your staff.
Inspectors documented the results of this inspection in the enclosed inspection report.
NRC inspectors documented three findings of very low safety significance (Green) in this report.
Two of these findings involved violations of NRC requirements. Further, inspectors documented
a licensee-identified violation which was determined to be of very low safety significance. The
NRC is treating this violation as a non-cited violation consistent with Section 2.3.2.a of the
If you contest the violations or significance of these NCVs, 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 IV; the Director, Office of Enforcement,
U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001; and the NRC resident
inspector at the Diablo Canyon Power Plant.
If you disagree with the cross-cutting aspects assignment or the finding not associated with a
regulatory requirement 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 Regional Administrator,
Region IV; and the NRC resident inspector at the Diablo Canyon Power Plant.
In accordance with Title 10 of the Code of Federal Regulations (10 CFR) 2.390, Public
Inspections, Exemptions, Requests for Withholding, a copy of this letter, its enclosure, and your
response (if any) will be available electronically for public inspection in the NRCs Public
Document Room or from the Publicly Available Records (PARS) component of the NRC's
E. Halpin
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Agencywide Documents Access and Management System (ADAMS). ADAMS is accessible
from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html (the Public Electronic
Reading Room).
Sincerely,
/RA/
Wayne C. Walker, Branch Chief
Project Branch A
Division of Reactor Projects
Docket Nos.: 05000275, 05000323
Enclosure:
NRC Inspection Report 05000275/2013005
and 05000323/2013005
w/ Attachment: Supplemental Information
cc w/ Enclosure: Electronic Distribution
SUNSI Rev Compl.
Yes No
Yes No
Reviewer Initials
WCW
Publicly Avail.
Yes No
Sensitive
Yes No
Sens. Type Initials
WCW
SRI:DRP/A
RI:DRP/D
RI:DRP/F
SPE:DRP/A
C:DRS/EB1
C:DRS/EB2
TRHipschman BDParks
WCSmith
RDAlexander
TRFarnholtz
GBMiller
/RA/ via Email /RA/ via Email /RA/ via Email /RA/
/RA/
/RA/
2/10/14
2/6/14
2/6/14
2/7/14
1/29/14
2/7/14
C:DRS/OB
C:DRS/PSB1
C:DRS/PSB2
C:DRS/TSB
BC:DRP/A
VGaddy
MSHaire
HGepford
RKellar
WWalker
/RA/
/RA/
/RA/
/RA/
/RA/
2/10/14
2/10/14
2/10/14
2/10/14
2/11/14
- 1 -
Enclosure
U.S. NUCLEAR REGULATORY COMMISSION
REGION IV
Docket:
05000275; 05000323
License:
Report:
05000275/2013005; 05000323/2013005
Licensee:
Pacific Gas and Electric Company
Facility:
Diablo Canyon Power Plant, Units 1 and 2
Location:
7 1/2 miles NW of Avila Beach
Avila Beach, CA
Dates:
September 22 through December 31, 2013
Inspectors: T. Hipschman, Senior Resident Inspector
G. Guerra, Emergency Preparedness Inspector, Plant Support Branch 1
R. Kumana, Resident Inspector, Projects Branch A
J. Laughlin, Emergency Preparedness Inspector, NSIR
B. Parks, Resident Inspector
C. Smith, Resident Inspector
Approved
By:
Wayne Walker
Chief, Project Branch A
Division of Reactor Projects
- 2 -
SUMMARY
IR 05000275/2013005, 05000323/2013005; 09/22/2013 - 12/31/2013; Diablo Canyon Power
Plant; Follow-up of Events and Notices of Enforcement Discretion
The inspection activities described in this report were performed between September 22, 2013,
and December 31, 2013, by the resident inspectors at Diablo Canyon Power Plant along with
two inspectors from the NRCs Region IV office and inspectors from other NRC offices. Three
findings of very low safety significance (Green) are documented in this report. Two of these
findings involved violations of NRC requirements. The significance of inspection findings is
indicated by their color (Green, White, Yellow, or Red), which is determined using Inspection
Manual Chapter 0609, Significance Determination Process. Their cross-cutting aspects are
determined using Inspection Manual Chapter 0310, Components Within the Cross-Cutting
Areas. Violations of NRC requirements are dispositioned in accordance with the NRC s
Enforcement Policy. The NRC's program for overseeing the safe operation of commercial
nuclear power reactors is described in NUREG-1649, Reactor Oversight Process.
Cornerstone: Initiating Events
Green. The inspectors reviewed a Green self-revealing non-cited violation of
10 CFR 50.65(a)(4), Requirements for Monitoring the Effectiveness of Maintenance at
Nuclear Power Plants, for failure to implement adequate oversight controls and risk
assessment while performing 500kV transmission line insulator maintenance on Unit 2. This
caused an initiating event due to a flashover on the main transformer lightning arrester that
resulted in a reactor trip.
The failure to effectively perform a risk assessment and properly control maintenance
activities that resulted in a reactor trip was a performance deficiency. The performance
deficiency was more than minor because it was associated with the human performance
attribute of the Initiating Events cornerstone and adversely affected the cornerstone
objective to limit the likelihood of events that upset plant stability and challenged critical
safety functions during power operations, and is therefore a finding. Using Inspection
Manual Chapter 0609, Attachment 04, Initial Characterization of Findings, and Appendix A,
Exhibit 1, Initiating Events Screening Questions, this finding was determined to be of very
low safety significance (Green) because, although it resulted in a reactor trip, it did not result
in the loss of mitigating equipment relied upon to transition the plant from the onset of the
trip to a stable shutdown condition. Additionally, using Inspection Manual Chapter 0612,
Appendix K, Maintenance Risk Assessment and Risk Management Significance
Determination Process, this finding was determined to be of very low safety significance
(Green). The licensee entered the condition into the corrective action program as
Notification 50572800.
This finding had a cross-cutting aspect in the area of human performance, associated with
the decision-making component, because the licensee did not demonstrate that nuclear
safety was an overriding priority during this maintenance activity. Specifically, the licensee
did not initially use conservative decision making in not properly categorizing the activity as
a reactor trip risk (despite internal and external operating experience to the contrary), and
again when the licensee did not terminate the hot washing activities when environmental
conditions degraded resulting in excessive water dispersion H.1(b). (Section 4OA3.1)
- 3 -
Green. The inspectors reviewed a Green self-revealing finding due to an inadequate
procedure for calibrating non-vital bus relays. This caused an initiating event due to a main
feed pump trip and unplanned downpower transient to 50 percent power on Unit 1.
The licensees failure to maintain an adequate maintenance procedure for calibrating non-
vital bus relays is a performance deficiency. Specifically, the procedure was inadequate in
that it contained an optional step to position a cut-out switch so that the relay would not de-
energize the bus if actuated during maintenance activities. The performance deficiency was
more than minor because, if left uncorrected, the performance deficiency had the potential
to lead to a more significant safety concern. In particular, when the bus de-energized and
tripped the running control oil pump, and the accumulator was unable to maintain system
pressure while the back-up control oil pump reached operating pressure, the main feed
pump tripped which resulted in a reactor power transient greater than 20 percent. Using
Inspection Manual Chapter 0609, Attachment 04, Initial Characterization of Findings, and
Appendix A, Exhibit 1, Initiating Events Screening Questions, this finding was determined
to be of very low safety significance (Green) because, although it resulted in a reactor
transient, it did not result in the loss of mitigating equipment relied upon to transition the
plant from the onset of the trip to a stable shutdown condition. This finding was entered into
the corrective action program as Notification 50588799.
This finding had a cross-cutting aspect in the area of human performance, associated with
the work control component, because the licensee did not adequately plan and coordinate
maintenance activities. Specifically, the licensee did not appropriately assess the job site
conditions that could impact human performance and human-system interface by failing to
incorporate operating experience into procedural guidance H.3(a). (Section 4OA3.2)
Cornerstone: Barrier Integrity
Green. The inspectors reviewed a Green self-revealing non-cited violation of
10 CFR Part 50, Appendix B, Criterion III, Design Control, after the licensee performed
a design change to the control room ventilation system (CRVS) that resulted in none of the
four CRVS pressurization fans being able to continuously operate if they started in response
to a Phase A containment isolation or control room radiation atmosphere intake actuation
signal. This resulted in declaring the Units 1 and 2 CRVS actuation instrumentation and
CRVS inoperable and unplanned entry into Technical Specifications (TS) 3.3.7, "Control
Room Ventilation System Actuation Instrumentation," and TS 3.7.10, "Control Room
Ventilation System," respectively.
The failure to use proper design control during the CRVS modification was a performance
deficiency. The performance deficiency was more than minor because it was associated
with the human performance attribute of the Barrier Integrity cornerstone, and it adversely
affected the cornerstone objective to provide reasonable assurance that physical design
barriers protect the public from radiological releases caused by accidents or events, and is
therefore a finding. Using Inspection Manual Chapter 0609, Attachment 04, Initial
Characterization of Findings, and Appendix A, Exhibit 3, Barrier Integrity Screening
Questions, this finding was determined to be of very low safety significance (Green)
because only the radiological barrier function of the control room was affected. The licensee
entered the condition into the corrective action program as Notification 50525605.
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The finding had a cross-cutting aspect in the area of human performance resources
component because licensee staff did not maintain complete, accurate, and up-to-date
design documentation - specifically, because the functions of the pressure switches and
CRVS interlocks had never been adequately described in design control documents H.2(c).
(Section 4OA3.3)
Licensee-Identified Violations
A violation of very low safety significance that was identified by the licensee has been reviewed
by the inspectors. Corrective actions taken or planned by the licensee have been entered into
the licensees corrective action program. This violation and associated corrective action
tracking numbers are listed in Section 4OA7 of this report.
- 5 -
PLANT STATUS
Unit 1 began the inspection period at essentially full power. On October 14, 2013, power was
reduced to 50 percent due to an unplanned loss of a main feedwater pump. Following
corrective maintenance, the unit returned to full power on October 17, 2013. On October 28,
Unit 1 commenced a controlled power reduction to 50 percent for planned circulating water
tunnel cleaning. Unit 1 returned to full power on November 3, 2013, and remained there for the
duration of the inspection period.
Unit 2 essentially remained at full power the entire inspection period.
REPORT DETAILS
1.
REACTOR SAFETY
Cornerstones: Initiating Events, Mitigating Systems, Barrier Integrity, and
1R01 Adverse Weather Protection (71111.01)
.1
Readiness for Seasonal Extreme Weather Conditions
a.
Inspection Scope
On December 12 and December 20, 2013, the inspectors completed an inspection of the
stations readiness for seasonal extreme weather conditions. The inspectors reviewed
the licensees adverse weather procedures for high winds and evaluated the licensees
implementation of these procedures. The inspectors verified that prior to high winds, the
licensee had corrected weather-related equipment deficiencies identified during the
previous winter.
The inspectors selected two risk-significant systems that were required to be protected
from high winds:
500kV offsite power
Unit 2 start-up transformer
The inspectors reviewed the licensees procedures and design information to ensure the
systems and components would remain functional when challenged by adverse weather.
The inspectors verified that operator actions described in the licensees procedures were
adequate to maintain readiness of these systems.
These activities constituted one sample of readiness for seasonal adverse weather, as
defined in Inspection Procedure 71111.01.
b.
Findings
No findings were identified.
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.2
Readiness for Impending Adverse Weather Conditions
a.
Inspection Scope
On October 8, 2013, the inspectors completed an inspection of the stations readiness
for impending adverse weather conditions. The inspectors reviewed plant design
features, the licensees procedures and planned actions to respond to the seasons first
rain, and the licensees planned implementation of these procedures. The inspectors
evaluated operator staffing and accessibility of controls and indications for those
systems required to control the plant.
These activities constituted one sample of readiness for impending adverse weather
conditions, as defined in Inspection Procedure 71111.01.
b.
Findings
No findings were identified.
.3
Readiness to Cope with External Flooding
a.
Inspection Scope
On November 3, 2013, the inspectors completed an inspection of the stations readiness
to cope with external flooding. After reviewing the licensees flooding analysis, the
inspectors chose two plant areas that were susceptible to flooding:
Unit 1 auxiliary salt water rooms
Unit 2 auxiliary salt water rooms
The inspectors reviewed plant design features and licensee procedures for coping with
flooding. The inspectors walked down the selected areas to inspect the design features,
including the material condition of seals, drains, and flood barriers. The inspectors
evaluated whether credited operator actions could be successfully accomplished.
These activities constituted one sample of readiness to cope with external flooding, as
defined in Inspection Procedure 71111.01.
b.
Findings
No findings were identified.
1R04 Equipment Alignment (71111.04)
.1
Partial Walkdown
a.
Inspection Scope
The inspectors performed partial system walk-downs of the following risk-significant
systems:
September 24, 2013, Unit 2, emergency diesel generator 2-2
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November 3, 2013, Unit 1, auxiliary salt water system
The inspectors reviewed the licensees procedures and system design information to
determine the correct lineup for the systems. They visually verified that critical portions
of the systems were correctly aligned for the existing plant configuration.
These activities constituted two partial system walk-down samples as defined in
Inspection Procedure 71111.04.
b.
Findings
No findings were identified.
.2
Complete Walkdown
a.
Inspection Scope
On November 22, 2013, the inspectors performed a complete system walk-down
inspection of the auxiliary feedwater pump 1-1. The inspectors reviewed the licensees
procedures and system design information to determine the correct auxiliary feedwater
lineup for the existing plant configuration. The inspectors also reviewed outstanding
work orders, open condition reports, in-process design changes, temporary
modifications, and other open items tracked by the licensees operations and
engineering departments. The inspectors then visually verified that the system was
correctly aligned for the existing plant configuration.
These activities constituted one complete system walk-down sample, as defined in
Inspection Procedure 71111.04.
b.
Findings
No findings were identified.
1R05 Fire Protection (71111.05)
.1
Quarterly Inspection
a.
Inspection Scope
The inspectors evaluated the licensees fire protection program for operational status
and material condition. The inspectors focused their inspection on four plant areas
important to safety:
October 1, 2013, Unit 1 and 2, fire areas 6-A-1, 6-A-2, 6-A-3, 6-B-1, 6-B-2, 6-B-3
October 7, 2013, Unit 1, emergency diesel generator rooms 1-1, 1-2, and 1-3
October 8, 2013, Unit 2, emergency diesel generator rooms 2-1, 2-2, and 2-3
October 29, 2013, Units 1 and 2 intake structure
For each area, the inspectors evaluated the fire plan against defined hazards and
defense-in-depth features in the licensees fire protection program. The inspectors
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evaluated control of transient combustibles and ignition sources, fire detection and
suppression systems, manual firefighting equipment and capability, passive fire
protection features, and compensatory measures for degraded conditions.
These activities constituted four quarterly inspection samples, as defined in Inspection
Procedure 71111.05.
b.
Findings
No findings were identified.
1R06 Flood Protection Measures (71111.06)
a.
Inspection Scope
The inspectors completed an inspection of the stations ability to mitigate flooding due to
internal causes. After reviewing the licensees flooding analysis, the inspectors chose
two plant areas containing risk-significant structures, systems, and components that
were susceptible to flooding:
November 4, 2013, Units 1 and 2, auxiliary salt water pump vaults
November 6, 2013, Unit 1, component cooling water heat exchanger room 1-1
The inspectors reviewed plant design features and licensee procedures for coping with
internal flooding. The inspectors walked down the selected areas to inspect the design
features, including the material condition of seals, drains, and flood barriers. The
inspectors evaluated whether operator actions credited for flood mitigation could be
successfully accomplished.
These activities constitute completion of two flood protection measures samples as
defined in Inspection Procedure 71111.06.
b.
Findings
No findings were identified.
1R07 Heat Sink Performance (71111.07)
a.
Inspection Scope
On December 20, 2013, the inspectors completed an inspection of the readiness and
availability of risk-significant heat exchangers. The inspectors reviewed the data from a
performance test for the Unit 2 containment fan cooler units.
These activities constitute completion of one heat sink performance annual review
sample, as defined in Inspection Procedure 71111.07.
b.
Findings
No findings were identified.
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1R11 Licensed Operator Requalification Program and Licensed Operator Performance
(71111.11)
.1
Review of Licensed Operator Requalification
a.
Inspection Scope
On October 18, 2013, the inspectors observed a crew of licensed operators in the plants
simulator during requalification testing. The inspectors assessed the following areas:
Licensed operator performance
The ability of the licensee to administer the evaluations
The quality of post-scenario critiques
These activities constitute completion of one quarterly licensed operator requalification
program sample, as defined in Inspection Procedure 71111.11.
b.
Findings
No findings were identified.
.2
Review of Licensed Operator Performance
a.
Inspection Scope
On October 14, 2013, and October 28, 2013, the inspectors observed the performance
of on-shift licensed operators in the plants main control room. At the time of the
observations, the plant was in a period of heightened activity due to reductions in plant
power. The inspectors observed the operators performance of the following activities:
Unit 1 post transient runback to 50 percent following the trip of main feed
pump 1-1
Unit 1 curtailment to 50 percent power for circulating water tunnel and condenser
cleaning
In addition, the inspectors assessed the operators adherence to plant procedures,
including conduct of operations procedures and other operations department policies.
These activities constitute completion of two quarterly licensed operator performance
samples, as defined in Inspection Procedure 71111.11.
b.
Findings
No findings were identified.
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1R12 Maintenance Effectiveness (71111.12)
a.
Inspection Scope
The inspectors reviewed one instance of degraded performance or condition of
safety-related structures, systems, and components (SSCs):
December 23, 2013, Units 1 and 2, plant radiation monitors
The inspectors reviewed the extent of condition of possible common cause SSC failures
and evaluated the adequacy of the licensees corrective actions. The inspectors
reviewed the licensees work practices to evaluate whether these may have played a
role in the degradation of the SSCs. The inspectors assessed the licensees
characterization of the degradation in accordance with 10 CFR 50.65 (the Maintenance
Rule) and verified that the licensee was appropriately tracking degraded performance
and conditions in accordance with the Maintenance Rule.
These activities constituted completion of one maintenance effectiveness sample, as
defined in Inspection Procedure 71111.12.
b.
Findings
No findings were identified.
1R13 Maintenance Risk Assessments and Emergent Work Control (71111.13)
a.
Inspection Scope
On October 10, 2013, the inspectors reviewed a risk assessment performed by the
licensee prior to a planned change in plant configuration and the risk management
actions planned by the licensee in response to elevated risk due to tracking on 230kV
transformers and the need for insulator cleaning.
The inspectors verified that this risk assessment was performed timely and in
accordance with the requirements of 10 CFR 50.65 (the Maintenance Rule) and plant
procedures. The inspectors reviewed the accuracy and completeness of the licensees
risk assessment and verified that the licensee implemented appropriate risk
management actions based on the result of the assessment.
On October 11, 2013, the inspectors observed portions of emergent work activities that
had the potential to affect the functional capability of mitigating systems due to a failed
stroke time test on auxiliary feedwater valve LCV-110.
The inspectors verified that the licensee appropriately developed and followed a work
plan for these activities. The inspectors verified that the licensee took precautions to
minimize the impact of the work activities on unaffected structures, systems, and
components (SSCs).
These activities constitute completion of two maintenance risk assessments and
emergent work control inspection samples, as defined in Inspection Procedure 71111.13.
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b.
Findings
No findings were identified.
1R15 Operability Determinations and Functionality Assessments (71111.15)
a.
Inspection Scope
The inspectors reviewed six operability determinations that the licensee performed for
degraded or nonconforming structures, systems, or components (SSCs):
October 15, 2013, operability determination of Unit 1, auxiliary feedwater
pump 1-2 after failed stroke test of LCV-110
October 17, 2013, operability determination of Unit 1 anticipated transient without
scram mitigation system actuation circuitry following testing
October 23, 2013, operability determination of Unit 1 control room Indications
after failure of a control panel transformer
October 25, 2013, operability determination of Unit 1 and Unit 2 emergency
diesel generators tornado capability
November 4, 2013, operability determination of Unit 1 condensate storage tank
piping upon the identification of corrosion
November 6, 2013 assessment of emergency diesel generator fuel oil
transformer pump 0-2
The inspectors reviewed the timeliness and technical adequacy of the licensees
evaluations. Where the licensee determined the degraded SSC to be operable, the
inspectors verified that the licensees compensatory measures were appropriate to
provide reasonable assurance of operability. The inspectors verified that the licensee
had considered the effect of other degraded conditions on the operability of the
degraded SSC.
These activities constitute completion of six operability and functionality review samples,
as defined in Inspection Procedure 71111.15.
b.
Findings
No findings were identified.
1R18 Plant Modifications (71111.18)
a.
Inspection Scope
On December 5, the inspectors reviewed a permanent plant modification to the Unit 2
plant computer system.
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The inspectors reviewed the design and implementation of the modification. The
inspectors verified that work activities involved in implementing the modification did not
adversely impact operator actions that may be required in response to an emergency or
other unplanned event. The inspectors verified that post-modification testing was
adequate to establish the functionality of the structures, systems, or components as
modified.
These activities constitute completion of one sample of permanent modifications, as
defined in Inspection Procedure 71111.18.
b.
Findings
No findings were identified.
1R19 Post-Maintenance Testing (71111.19)
a.
Inspection Scope
The inspectors reviewed four post-maintenance testing activities that affected
risk-significant structures, systems, or components (SSCs):
October 2, 2013, Unit 2, emergency diesel generator 2-1
November 19, 2013 Unit 1, emergency diesel generator 1-3
December 3, 2013, Unit 2, auxiliary feedwater pump 2-2
December 23, 2013, Unit 1, emergency diesel generator 1-3
The inspectors reviewed licensing- and design-basis documents for the SSCs and the
maintenance and post-maintenance test procedures. The inspectors observed the
performance of the post-maintenance tests to verify that the licensee performed the tests
in accordance with approved procedures, satisfied the established acceptance criteria,
and restored the operability of the affected SSCs.
These activities constitute completion of four post-maintenance testing inspection
samples, as defined in Inspection Procedure 71111.19.
b.
Findings
No findings were identified.
1R22 Surveillance Testing (71111.22)
a.
Inspection Scope
The inspectors observed four risk-significant surveillance tests and reviewed test results
to verify that these tests adequately demonstrated that the structures, systems, and
components (SSCs) were capable of performing their safety functions:
- 13 -
Inservice tests:
October 15, 2013, Stroke Test of Unit 1, auxiliary feedwater pump 1-2
valve LCV-110
November 5, 2013, surveillance test of motor driven auxiliary feedwater
pump 1-2
Other surveillance tests:
October 17, 2013, Functional Test of Unit 1 anticipated transient without scram
mitigation system actuation circuitry
December 23, 2013, Unit 1, surveillance test of emergency diesel generator 1-3
The inspectors verified that these tests met technical specification requirements, that the
licensee performed the tests in accordance with their procedures, and that the results of
the test satisfied appropriate acceptance criteria.
These activities constitute completion of four surveillance testing inspection samples, as
defined in Inspection Procedure 71111.22.
b.
Findings
No findings were identified.
Cornerstone: Emergency Preparedness
1EP2 Alert and Notification System Testing (71114.02)
a.
Inspection Scope
The inspectors discussed with licensee staff the operability of offsite siren emergency
warning systems and backup alerting methods to determine the adequacy of licensee
methods for testing the alert and notification system in accordance with 10 CFR Part 50,
Appendix E. The licensees alert and notification system testing program was compared
with criteria in NUREG-0654, Criteria for Preparation and Evaluation of Radiological
Emergency Response Plans and Preparedness in Support of Nuclear Power Plants,
Revision 1; FEMA Report REP-10, Guide for the Evaluation of Alert and Notification
Systems for Nuclear Power Plants, and the licensees current FEMA-approved alert
and notification system design report, Alert and Notification Design Report, Revision 1.
The specific documents reviewed during this inspection are listed in the attachment.
These activities constitute completion of one sample as defined in Inspection
Procedure 71114.02.
b.
Findings
No findings were identified.
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1EP3 Emergency Response Organization Staffing and Augmentation System (71114.03)
a.
Inspection Scope
The inspectors discussed with licensee staff the operability of primary and back-up
systems for augmenting the on-shift emergency response staff to determine the
adequacy of licensee methods for staffing emergency response facilities in accordance
with the requirements of 10 CFR Part 50, Appendix E. The inspectors reviewed licensee
methods for staffing alternate emergency response facilities. The inspectors also
reviewed periodic surveillances of the augmentation system to determine the licensees
ability to staff emergency response facilities within the response times described in the
site emergency plan. The specific documents reviewed during this inspection are listed
in the attachment.
These activities constitute completion of one sample as defined in Inspection
Procedure 71114.03.
b.
Findings
No findings were identified.
1EP4 Emergency Action Level and Emergency Plan Changes (71114.04)
a.
Inspection Scope
The Office of Nuclear Security and Incident Response (NSIR) headquarters staff
performed an in-office review of the latest revisions of various Emergency Plan
Implementing Procedures (EPIPs) and the Emergency Plan located under ADAMS
accession numbers ML13269A256 and ML13277A112 as listed in the Attachment.
The licensee determined that in accordance with 10 CFR 50.54(q), the changes made in
the revisions resulted in no reduction in the effectiveness of the Plan, and that the
revised Plan continued to meet the requirements of 10 CFR 50.47(b) and Appendix E to
10 CFR Part 50. The NRC review was not documented in a safety evaluation report and
did not constitute approval of licensee-generated changes; therefore, this revision is
subject to future inspection. The specific documents reviewed during this inspection are
listed in the Attachment.
These activities constitute completion of three samples as defined in Inspection
Procedure 71114.04 05.
b.
Findings
No findings were identified.
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1EP5 Maintenance of Emergency Preparedness (71114.05)
a.
Inspection Scope
The inspectors reviewed licensee records associated with maintaining the emergency
preparedness program between August 2011 and November 2013, including:
Licensee procedures
After-action reports
Quality Assurance audit and surveillance reports
Program assessments
Drill and exercise evaluation reports
Assessments of the impact of changes to the emergency plan and emergency
plan implementing procedures
Maintenance records for equipment important to emergency preparedness
The inspectors reviewed summaries of 725 corrective action program entries assigned
to the emergency preparedness department and emergency response organization and
selected 32 for detailed review against the program requirements. The inspectors
evaluated the response to the corrective action requests to determine the licensees
ability to identify, evaluate, and correct problems in accordance with the licensee
program requirements, planning standard 10 CFR 50.47(b)(14), and 10 CFR Part 50,
Appendix E.
The inspectors reviewed summaries of 103 assessments of the impact of changes to the
emergency plan and emergency plan implementing procedures and selected 5 for
detailed review against program requirements. The inspectors also visited the licensees
alternate emergency response facilities and reviewed their procedures for use when
access to the site is restricted. The specific documents reviewed during this inspection
are listed in the attachment.
These activities constitute completion of one sample as defined in Inspection
Procedure 71114.05.
b.
Findings
Unresolved Item - Procedures for Recommending Protective Actions for Members of the
Public on the Pacific Ocean
Introduction. The inspectors identified an unresolved item associated with the
implementation of the licensees process to make protective action recommendations
within the ten mile emergency planning zone (EPZ). This item remains unresolved
- 16 -
pending further NRC staff review to determine if this issue constitutes a violation of NRC
requirements.
Description. The inspectors determined that the licensee does not make protective
action recommendations for members of the public on the ocean within ten miles of the
plant. The licensee also does not notify the United States Coast Guard (USCG) of
emergency events. A requirement to make direct notifications was removed from the
licensees emergency plan implementing procedures (EPIP) in 2003. The licensee relies
on the San Luis Obispo County government to notify the USCG to take any actions
necessary to protect members of the public. The county has procedures which include a
default action to recommend the USCG evacuate waterborne vessels within five nautical
miles if the licensee notifies the county of a general emergency. The USCG has
additional guidance recommending a two nautical mile safety zone for an alert or site
area emergency. The licensee had initiated a condition report on November 12, 2013,
identifying that other sites make protective action recommendations for water areas.
Title 10 of the Code of Federal Regulations Part 50.54(q)(2) requires the licensee
to maintain an emergency plan that meets the planning standards outlined in
10 CFR 50.47(b). The planning standard outlined in 10 CFR 50.47(b)(10) requires
the licensee to provide a range of protective actions for emergency workers and
members of the public in the plume exposure pathway EPZ. NUREG-0654 generally
defines the plume exposure EPZ as ten miles radius from the plant. The EPZ may
be defined with alternate boundaries by the licensee if an adequate basis exists.
Title 10 of the Code of Federal Regulations Part 50.54(q)(3) requires the licensee to
obtain NRC approval for changes to the emergency plan, or perform an analysis
demonstrating the changes do not reduce the effectiveness of the plan. The licensee
did not obtain prior NRC approval for the 2003 revision to the EPIPs removing the direct
notification to the USCG of emergency declarations.
This issue remains unresolved pending further NRC review of additional information to
address the concerns described above, in order to determine the adequacy of the
licensees emergency plan and implementing procedures, whether the licensees
protective actions recommendations procedure is consistent with their licensing basis,
and whether or not the issue represents a violation of 10 CFR 50.54(q)(2). In addition,
more information is required to determine if the revision to the implementing procedures
removing the requirement to make a direct notification to the USCG constitutes a
violation of 10 CFR 50.54(q)(3).
This issue is being tracked as URI 05000275/2013005-01; 05000323/2013005-01;
Unresolved Item - Procedures for Recommending Protective Actions for Members of
the Public on the Pacific Ocean.
1EP6 Drill Evaluation (71114.06)
Emergency Preparedness Drill Observation
a.
Inspection Scope
The inspectors observed an emergency preparedness drill on October 30, 2013, to verify
the adequacy and capability of the licensees assessment of drill performance. The
inspectors reviewed the drill scenario, observed the drill from the Technical Support
- 17 -
Center, and reviewed the post-drill critique. The inspectors verified that the licensees
emergency classifications, off-site notifications, and protective action recommendations
were appropriate and timely. The inspectors verified that any emergency preparedness
weaknesses were appropriately identified by the licensee in the post-drill critique and
entered into the corrective action program for resolution.
These activities constitute completion of one emergency preparedness drill observation
sample, as defined in Inspection Procedure 71114.06-05.
b.
Findings
No findings were identified.
4.
OTHER ACTIVITIES
Cornerstones: Initiating Events, Mitigating Systems, Barrier Integrity, Emergency
Preparedness, Public Radiation Safety, Occupational Radiation Safety, and
Security
4OA1 Performance Indicator Verification (71151)
.1
Data Submission Issue
a.
Inspection Scope
The inspectors performed a review of the data submitted by the licensee for the
third quarter 2013 performance indicators for any obvious inconsistencies prior to its
public release in accordance with Inspection Manual Chapter 0608, Performance
Indicator Program.
This review was performed as part of the inspectors normal plant status activities and,
as such, did not constitute a separate inspection sample.
b.
Findings
No findings were identified.
.2
Reactor Coolant System Specific Activity (BI01)
a.
Inspection Scope
The inspectors reviewed the licensees reactor coolant system chemistry sample
analyses for the period of September 2012 through September 2013 to verify the
accuracy and completeness of the reported data. The inspectors used definitions and
guidance contained in Nuclear Energy Institute Document 99-02, Regulatory
Assessment Performance Indicator Guideline, Revision 7, to determine the accuracy of
the reported data.
These activities constituted verification of the reactor coolant system specific activity
performance indicator for Units 1 and 2, as defined in Inspection Procedure 71151.
- 18 -
b.
Findings
No findings were identified.
.3
Reactor Coolant System Identified Leakage (BI02)
a.
Inspection Scope
The inspectors reviewed the licensees records of reactor coolant system (RCS)
identified leakage for the period of September 2012 through September 2013 to verify
the accuracy and completeness of the reported data. The inspectors reviewed the
performance of RCS leakage surveillance procedure on October 7, 2013. The
inspectors used definitions and guidance contained in Nuclear Energy Institute
Document 99-02, Regulatory Assessment Performance Indicator Guideline, Revision 7,
to determine the accuracy of the reported data.
These activities constituted verification of the reactor coolant system specific activity
performance indicator for Units 1 and 2, as defined in Inspection Procedure 71151.
b.
Findings
No findings were identified.
.4
Drill/Exercise Performance (EP01)
a.
Inspection Scope
The inspectors sampled licensee submittals for the Drill and Exercise Performance,
performance indicator for the period October 2012 through September 2013 to
determine the accuracy of the licensees reported performance indicator data. The
inspectors reviewed the licensees records associated with the performance indicator to
verify that the licensee accurately reported the indicator in accordance with relevant
procedures and Nuclear Energy Institute Document 99-02, Regulatory Assessment
Performance Indicator Guideline, Revision 7. Specifically, the inspectors reviewed
licensee records and processes including procedural guidance on assessing
opportunities for the performance indicator; assessments of performance indicator
opportunities during pre-designated control room simulator training sessions,
performance during the 2012 biennial exercise, and performance during other drills. The
specific documents reviewed are described in the attachment to this report.
These activities constitute completion of the drill/exercise performance sample as
defined in Inspection Procedure 71151.
b.
Findings
No findings were identified.
- 19 -
.5
Emergency Response Organization Drill Participation (EP02)
a.
Inspection Scope
The inspectors sampled licensee submittals for the Emergency Response Organization
Drill Participation performance indicator for the period October 2012 through
September 2013 to determine the accuracy of the licensees reported performance
indicator data. The inspectors reviewed the licensees records associated with the
performance indicator to verify that the licensee accurately reported the indicator in
accordance with relevant procedures and Nuclear Energy Institute Document 99-02,
Regulatory Assessment Performance Indicator Guideline, Revision 7. Specifically, the
inspectors reviewed licensee records and processes including procedural guidance on
assessing opportunities for the performance indicator, rosters of personnel assigned to
key emergency response organization positions, and exercise participation records. The
specific documents reviewed are described in the attachment to this report.
These activities constitute completion of the emergency response organization drill
participation sample as defined in Inspection Procedure 71151.
b.
Findings
No findings were identified.
.6
Alert and Notification System Reliability (EP03)
a.
Inspection Scope
The inspectors sampled licensee submittals for the Alert and Notification System
performance indicator for the period October 2012 through September 2013 to
determine the accuracy of the licensees reported performance indicator data. The
inspectors reviewed the licensees records associated with the performance indicator to
verify that the licensee accurately reported the indicator in accordance with relevant
procedures and Nuclear Energy Institute Document 99-02, Regulatory Assessment
Performance Indicator Guideline, Revision 7. Specifically, the inspectors reviewed
licensee records and processes including procedural guidance on assessing
opportunities for the performance indicator and the results of periodic alert notification
system operability tests. The specific documents reviewed are described in the
attachment to this report.
These activities constitute completion of the alert and notification system sample as
defined in Inspection Procedure 71151.
b.
Findings
No findings were identified.
- 20 -
4OA2 Problem Identification and Resolution (71152)
.1
Routine Review
a.
Inspection Scope
Throughout the inspection period, the inspectors performed daily reviews of items
entered into the licensees corrective action program. The inspectors verified that
licensee personnel were identifying problems at an appropriate threshold and entering
these problems into the corrective action program for resolution. The inspectors verified
that the licensee developed and implemented corrective actions commensurate with the
significance of the problems identified. The inspectors also reviewed the licensees
problem identification and resolution activities during the performance of the other
inspection activities documented in this report.
b.
Findings
No findings were identified.
.2
Semiannual Trend Review
a.
Inspection Scope
The inspectors performed a review of the licensees corrective action program and
associated documents to identify trends that could indicate the existence of a more
significant safety issue. In particular, the inspectors focused their review on notifications
and several root cause reports completed in the last year which involved human
performance issues, including:
Three instances of loss of start-up power (May 2011)
Low temperature overpressure protection inoperable to technician error (June 2012)
Reactor trip due to a high voltage insulator flashover (October 2012)
Control room ventilation system fans inadequate design modification
(November 2012)
Inadvertent de-energizing of 4kV bus G (February 2013)
Containment isolation valve S-2-200 mispositioned during a mode change
(March 2013)
Three emergency diesel generators inoperable concurrently (June 2013)
500kV insulator hot washing results in a reactor trip (July 2013)
Unit 2 spent fuel handling error (July 2013)
Locked high radiation area found unlocked (October 2013)
Main feed pump trip and reactor power transient due to inadvertent relay actuation
(October 2013)
Auxiliary salt water cross tie valve found closed (November 2013)
Emergency diesel generator inoperable due to a fuel oil leak (December 2013)
Radiation monitors RM11 and 12 inoperable as a result of a maintenance activity
(December 2013)
- 21 -
The inspectors reviewed documents and interviewed personnel to determine if the
licensee completely and accurately identified problems in a timely manner
commensurate with its significance, evaluated and dispositioned operability issues,
considered the extent of conditions and causes, prioritized the problem commensurate
with its safety significance, identified appropriate corrective actions, and completed
corrective actions in a timely manner commensurate with the safety significance of the
issue.
These activities constitute completion of one semi-annual trend review inspection
sample as defined in Inspection Procedure 71152.
b.
Findings
No findings were identified. However, the inspectors identified that while the licensee
appropriately identified and entered these individual issues into the corrective action
program, the root and apparent causes and associated corrective actions were limited in
station-wide application. Specifically, the inspectors identified a common theme in the
licensees cause evaluations which focused on maintenance leadership not consistently
reinforcing human performance standards and error reduction tools. The licensee
agreed with the inspectors observations and entered the issue into the corrective action
program as Notification 50601631, requiring a root cause evaluation to assess and take
corrective actions relative to the adverse human performance trend more broadly than
was completed for the individual station events.
.3
Annual Follow-up of Selected Issues
a.
Inspection Scope
The inspectors selected three issues for an in-depth follow-up:
On October 22, 2013, the inspectors reviewed corrective actions associated with
a Green non-cited violation issued in the first quarter of 2010 for failure to follow
the requirements of the Seismically Induced System Interaction Program (SISIP)
with respect to the stowage and anchoring of potential seismic hazards. The
inspectors evaluated the licensees current compliance with the program, to
include a walkdown of locations in the plant and a review of a sample of required
seismic hazard evaluations. The inspectors assessed the licensees problem
identification threshold, cause analyses, extent of condition reviews and
compensatory actions for the violation. The inspectors verified that the licensee
appropriately prioritized the planned corrective actions and that these actions
were adequate to correct the condition.
On November 27, 2013, the inspectors reviewed the diesel fuel oil storage and
supply system components, particularly for the fuel oil flow transmitter FIT-168.
The inspectors identified that this flow transmitter was found out of tolerance on
several occasions, and that there were no preventative maintenance activities
scheduled between surveillance tests of the fuel oil transfer system. The
inspectors interviewed the system engineer and reviewed the Maintenance
Rule (a).1 plan for planned corrective actions. In addition, the inspectors
independently verified that the inaccurate fuel flow readings from the FIT-168 fuel
- 22 -
flow transmitter could not affect the surveillance test results, because separate
fuel oil level indicators are used to verify the fuel system is transferring the proper
amount of fuel oil.
The inspectors conducted a cumulative review of operator workarounds during
the period December 2-6, 2012, for Units 1 and 2, and assessed the
effectiveness of the operator workaround program to verify that the licensee was:
(1) identifying operator workaround problems at an appropriate threshold;
(2) entering them into the corrective action program; and (3) identifying and
implementing appropriate corrective actions. The review included walkdowns of
the control room panels, interviews with licensed operators and reviews of the
control room discrepancies list, the lit annunciators list, the operator burden list,
and the operator workaround list.
The inspectors assessed the licensees problem identification threshold, cause analyses,
extent of condition reviews, and compensatory actions. The inspectors verified that the
licensee appropriately prioritized the planned corrective actions and that these actions
were adequate.
These activities constitute completion of three annual follow-up samples, which included
one operator work-around sample.
b.
Findings
No findings were identified.
4OA3 Follow-up of Events and Notices of Enforcement Discretion (71153)
.1
(Closed) 05000323/2013-005-01: Unit 2 Reactor Trip due to Lightning Arrester
Flashover
Introduction. The inspectors reviewed a Green self-revealing non-cited violation of
10 CFR 50.65(a)(4), Requirements for Monitoring the Effectiveness of Maintenance at
Nuclear Power Plants for failure to implement adequate oversight controls and risk
assessment while performing 500kV transmission line insulator maintenance on Unit 2.
This caused an initiating event due to a flashover on the main transformer lightning
arrester that resulted in a reactor trip.
Description. On July 10, 2013, with Diablo Canyon Power Plant Unit 2 at 100 percent
power, PG&E personnel were performing periodic hot washing of 500kV transmission
line insulators. The purpose of hot washing the insulators is to remove contaminants
that can degrade the mechanical and insulating properties which could result in a
flashover. A flashover is a high voltage short-circuit to ground event. During the hot
washing of the Unit 2 500kV Phase A dead-end insulators, an overspray of wash water
drifted onto the 500kV main transformer Phase A lightning arrester, resulting in a
flashover to ground. This actuated the 500kV differential protection relay, which opened
the Unit 2 main generator output breakers as designed. This resulted in a Unit 2 main
turbine trip, and a reactor protection reactor trip, also as designed. The reactor
protection system and engineered safeguards features performed as expected, and
operators placed Unit 2 in a hot shutdown condition. There were no complications other
- 23 -
than damage to the A Phase lightning arrester. Following repairs, Unit 2 was returned to
service on July 14, 2013.
The inspectors reviewed the licensees root-cause evaluation, as well as conducted an
independent review. The inspectors determined the licensee appropriately identified that
the root cause of the flashover event was a result of inadequate controls that lead to
wash water drifting on the A Phase lightning arrester. The water stream overspray
containing dissolved dirt and sea salts was driven by wind onto the lightning arrester,
overloading its ability to provide adequate resistance to ground, which resulted in a
flashover. PG&E personnel did not take appropriate controls to stop the hot washing
activity during a period when wind conditions resulted in excessive water dispersion,
fogging, or overspray, contrary to PG&E transmission line washing requirements and
techniques.
Additionally, the licensee failed to adequately assess the maintenance risk by
categorizing the activity as a non-trip risk. Conflicting guidance and a change to
procedure AD7.DC6, On-line Maintenance Risk Management, resulted in licensee staff
inappropriately categorizing the hot wash activity as a non-trip risk, when it should have
been classified as a low trip risk. The basis for the hot washing preventative
maintenance was not properly documented in the licensee preventive maintenance
procedure, MA1.DC51. Because of this, the risk assessment changed over time from
being characterized as a trip risk, to a non-trip risk. The trip risk was screened out per
Procedure AD7.DC6, On-line Maintenance Risk Management, as an activity which
could not directly cause a reactor trip. Guidance in Section 3.15 of Procedure AD7.DC6
defined a risk activity as something that can significantly increase the probability of a
reactor or turbine trip. Additionally, PG&E Grid Control Center operations routinely listed
hot washing as a trip risk. Further, the licensee did not identify several industry and
internal PG&E Electric Operations operating experience events that identified the
potential for a flashover due to hot washing activities.
The inspectors reviewed the licensees corrective actions which included suspending hot
washing activities. Diablo Canyon personnel began hot washing the 500kV insulators at
a six-week frequency in 1996 in response to a failed insulator at a PG&E substation.
Prior to 1996, the 500kV dead-end insulators were washed during refueling outages.
As a result of this event, Diablo Canyon staff analyzed the periodicity of performing the
500kV insulators hot washes. The licensee determined that based on operating
experience and existing design, the insulators have sufficient margin to defer the
maintenance activity until the next refueling outage.
Analysis. The failure to effectively perform a risk assessment and properly control
maintenance activities that resulted in a reactor trip on July 10, 2013, was a performance
deficiency. The performance deficiency was more than minor because it was associated
with the human performance attribute of the Initiating Events cornerstone and adversely
affected the cornerstone objective to limit the likelihood of events that upset plant
stability and challenged critical safety functions during power operations, and is therefore
a finding. Using Inspection Manual Chapter 0609, Attachment 04, Initial
Characterization of Findings, and Appendix A, Exhibit 1, Initiating Events Screening
Questions, this finding was determined to be of very low safety significance (Green)
because, although it resulted in a reactor trip, it did not result in the loss of mitigating
equipment relied upon to transition the plant from the onset of the trip to a stable
- 24 -
shutdown condition. Additionally, using Inspection Manual Chapter 0612, Appendix K,
Maintenance Risk Assessment and Risk Management Significance Determination
Process, this finding was determined to be of very low safety significance (Green).
This finding had a cross-cutting aspect in the area of human performance, associated
with the decision-making component, because the licensee did not demonstrate that
nuclear safety was an overriding priority during this maintenance activity. Specifically, the
licensee did not initially use conservative decision making in not properly categorizing
the activity as a reactor trip risk (despite internal and external operating experience to
the contrary), and again when the licensee did not terminate the hot washing activities
when environmental conditions degraded resulting in excessive water dispersion.
Enforcement. This finding is also a violation of 10 CFR 50.65(a)(4), which requires that
before performing maintenance activities including, but not limited to, surveillance,
post-maintenance testing, and corrective and preventive maintenance, the licensee shall
assess and manage the increase in risk that may result from the proposed maintenance
activities. The scope of the assessment includes non-safety-related structures, systems
and components whose failure could cause a reactor scram or actuation of a safety-
related system. Contrary to this requirement, the licensee failed to assess the
maintenance activity as a reactor trip initiating event by classifying the activity as a
non-trip risk. Because this finding was of very low safety significance and was entered
into the corrective action program as Notification 50579100, this violation is being
treated as a non-cited violation, consistent with Section 2.3.2 of the NRC Enforcement
Policy: NCV 05000323/20130055-02, Reactor Trip due to a Lightning Arrester
Flashover.
.2
(Closed) LER 05000275/2013-007-00: Auxiliary Feedwater Actuation Due to a Main
Feedwater Pump Trip
Introduction. The inspectors reviewed a Green self-revealing finding due to an
inadequate procedure for calibrating non-vital bus relays. This caused an initiating event
due to a main feed pump trip and unplanned downpower transient to 50 percent power
on Unit 1.
Description. On October 14, 2013, with Unit 1 at 100 percent power, main feedwater
pump 1-1 tripped. This event began when maintenance technicians inadvertently
contacted a 480V bus overcurrent relay. When the relay tripped, the non-vital 480V bus
15D de-energized. As a result, the inservice control oil pump tripped, and the backup
control oil pump started as designed; however, a degraded control oil system
accumulator was not able to maintain control oil system pressure long enough for the
back-up control oil pump to develop pressure before the main feed pump 1-1 protective
logic tripped the pump. In response, plant operators rapidly reduced power from
100 percent to 50 percent power and manually started the auxiliary feedwater pumps per
plant procedures and conditions. Feedwater and turbine control systems operated as
designed, mitigating the loss of a single feed pump from full power.
Diablo Canyon personnel determined that the cause of the relay trip was failure to
incorporate operating experience in the relay maintenance procedure. Operating
experience documented that it was possible for the relay covers reset arm to come into
contact with the relay during replacement of the cover following the calibration. The
- 25 -
calibration procedure contained an optional step to position a cut-out switch so that the
relay would not de-energize the bus if actuated. Although technicians discussed
whether they should reposition the switch, they determined it was not necessary. The
technicians were unaware that the cover lever could come in contact with the relay and
actuate the trip circuit. Inadequate procedural guidance and not incorporating operating
experience were identified as causes for the unintended bus de-energization.
Normally, a single bus de-energization should not result in a plant power transient
because plant systems have backup or redundant equipment to provide for reliability.
Although the main feed pump 1-1 back-up oil pump started as designed upon the loss of
the running control oil pump, the control oil accumulator did not maintain system
pressure as designed, resulting in the protective action to trip the main feed pump.
PG&E missed an opportunity to identify and correct the degraded accumulator prior to
this event. On June 29, 2013, while preparing to exit a forced outage, main feed
pump 1-1 was placed into service. Operators noticed an abnormal low nitrogen
pressure on the accumulator and initiated a notification to resolve the problem. In the
evaluation, engineering personnel did not fully identify the problem with the accumulator
not maintaining pressure and did not provide an adequate corrective action before
returning it to service. This created a hidden system vulnerability when the bus 15D
de-energization tripped the running control oil pump and the accumulator was unable to
maintain system pressure while the back-up control oil pump reached operating
pressure. Following this event, maintenance personnel replaced the accumulator
bladder.
Analysis. The licensees failure to maintain an adequate maintenance procedure for
calibrating non-vital bus relays is a performance deficiency. Specifically, the procedure
was inadequate in that it contained an optional step to position a cut-out switch so that
the relay would not de-energize the bus if actuated during maintenance activities. The
performance deficiency was more than minor because, if left uncorrected, the
performance deficiency had the potential to lead to a more significant safety concern. In
particular, when the bus de-energized and tripped the running control oil pump, and the
accumulator was unable to maintain system pressure while the back-up control oil pump
reached operating pressure, the main feed pump tripped which resulted in a reactor
power transient greater than 20 percent. Using Inspection Manual Chapter 0609,
Attachment 04, Initial Characterization of Findings, and Appendix A, Exhibit 1, Initiating
Events Screening Questions, this finding was determined to be of very low safety
significance (Green) because, although it resulted in a reactor transient, it did not result
in the loss of mitigating equipment relied upon to transition the plant from the onset of
the trip to a stable shutdown condition.
This finding had a cross-cutting aspect in the area of human performance, associated
with the work control component, because the licensee did not adequately plan and
coordinate maintenance activities. Specifically, the licensee did not appropriately assess
the job site conditions that could impact human performance and human-system
interface by failing to incorporate operating experience into procedural guidance. H.3(a)
Enforcement. This finding does not involve enforcement action because no regulatory
requirement was identified. This finding was placed in the licensees corrective action
program as Notifications 50598753, 50588110, and 50588799. Because this finding
does not involve a violation and is of very low safety significance (Green), it is identified
- 26 -
as a finding: FIN 05000275/2013005-03, Auxiliary Feedwater Actuation Due to a Main
Feedwater Pump Trip.
.3
(Closed) LER 05000275; 05000323/2012-008-00: Loss of Control Room Ventilation
System Due to Inadequate Design Control
Introduction. The inspectors reviewed a Green self-revealing non-cited violation of
10 CFR Part 50, Appendix B, Criterion III, Design Control, after the licensee performed
a design change to the control room ventilation system (CRVS) that resulted in none of
the four CRVS pressurization fans being able to continuously operate if they started in
response to a Phase A containment isolation or control room radiation atmosphere
intake actuation signal. This resulted in declaring the Units 1 and 2 CRVS actuation
instrumentation and CRVS inoperable, and an unplanned entry into Technical
Specification (TS) 3.3.7, "Control Room Ventilation System Actuation Instrumentation,"
and TS 3.7.10, "Control Room Ventilation System," respectively.
Description. In October 2012, Diablo Canyon personnel completed modifications and
testing of the Units 1 and 2 CRVS by adding a back-draft damper in each unit's CRVS
recirculation line. These dampers were designed to minimize the amount of unfiltered
air entering the control room when one train is not in operation.
On November 27, 2012, while performing a functional test of the CRVS pressurization
system, operators identified that none of the four CRVS pressurization fans would
continuously operate if they started in response to a safety injection or control room
atmosphere intake radiation actuation signal. Operators declared the Units 1 and 2
CRVS actuation instrumentation inoperable and entered TS 3.3.7, "Control Room
Ventilation System Actuation Instrumentation," as directed by TS 3.3.7, Condition B,
operators also declared one train of CRVS inoperable and entered TS 3.7.10,
Condition A.
Licensee troubleshooting efforts determined that the recent installation of back-draft
dampers and post-modification CRVS flow balancing resulted in a higher static head in
CRVS common ducting during recirculation operation. This caused pressurization fan
cycling due to actuation of the system pressure switches. The original pressurization
system design utilized pressure switches to provide interlocks which precluded running
two fans simultaneously by causing the non-associated fan to shut off. This feature was
originally designed to protect against over pressurization of the system ducting. Soon
after initial system construction, the pressurization fans were modified such that over-
pressurization was no longer possible, but the pressure interlocks remained in the
actuation circuitry. Per design basis document Design Criteria Memorandum
(DCM) S-23F, "Control Room HVAC System," the pressure switches were only identified
as providing a low pressure permissive to start a redundant fan. Therefore, engineers
involved in the damper modification and flow rebalancing did not recognize that the
same pressure switches also provided an over-pressurization interlock. Following these
modifications, the pressurization fan that was selected to run increased static pressure in
ducting downstream of the pressurization fans enough to exceed the setpoint of all the
pressure switches that indicate their associated fan is running. Thus, this condition
caused the operating fan to shut down, which lowered the common-header static
pressure below the setpoint of the pressure switch. This reduction of static pressure in
the common header resulted in the restart of the pressurization fan. Thus, with the on-
- 27 -
and-off cycling of the pressurization fan, the control room ventilation recirculation mode
would not be sustained upon a Phase A containment isolation or radiation monitor
actuation. However, Mode 4 CRVS operation could be sustained by control room
operator manual action taken as directed by DCPP Emergency Operating
Procedure E-0, "Reactor Trip or Safety Injection," Appendix E, "ESP Auto Actions,
Secondary and Auxiliaries Status."
Analysis. The failure to use proper design control during the CRVS modification was a
performance deficiency. The performance deficiency was more than minor because it
was associated with the human performance attribute of the Barrier Integrity
cornerstone, and it adversely affected the cornerstone objective to provide reasonable
assurance that physical design barriers protect the public from radiological releases
caused by accidents or events, and is therefore a finding. Using Inspection Manual
Chapter 0609, Attachment 04, Initial Characterization of Findings, and Appendix A,
Exhibit 3, Barrier Integrity Screening Questions, this finding was determined to be of
very low safety significance (Green) because only the radiological barrier function of the
control room was affected. The finding had a cross-cutting aspect in the area of human
performance resources component because licensee staff did not maintain complete,
accurate, and up-to-date design documentation. Specifically, because the functions of
the pressure switches and CRVS interlocks had never been adequately described in
design control documents. H.2(c)
Enforcement. Title 10 of the Code of Federal Regulations, 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
§ 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. Measures shall also be established for the
selection and review for suitability of application of materials, parts, equipment, and
processes that are essential to the safety-related functions of the structures, systems
and components. Contrary to the above, in October 2012, the licensee completed a
design change to the control room ventilation system that resulted in none of the four
CRVS pressurization fans being able to continuously operate if they started in response
to a Phase A containment isolation or control room radiation atmosphere intake actuation
signal. This resulted in declaring the Units 1 and 2 CRVS actuation instrumentation and
CRVS inoperable and an unplanned entry into Technical Specifications (TS) 3.3.7,
"Control Room Ventilation System Actuation Instrumentation," and TS 3.7.10, "Control
Room Ventilation System," respectively. Because this finding was of very low safety
significance and was entered into the corrective action program as Notification
50525605, this violation is being treated as a non-cited violation consistent with
Section 2.3.2 of the NRC Enforcement Policy: NCV 05000275;05000323/2012008-04,
Loss of Control Room Ventilation System Due to Inadequate Design Control.
.4
(Closed) Licensee Event Report (LER) 05000275/1-2013-004-00: All Three Unit 1
Emergency Diesel Generators Momentarily Inoperable
On June 23, 2103, following a loss of 230kV offsite power, Unit 1 control room operators
did not enter LCO 3.0.3 when they simultaneously made all three emergency diesel
generators inoperable by simultaneously placing them all in manual. When 230kV
startup power to the site was lost due to an electrical fault on the grid, all diesel
- 28 -
generators started automatically, as designed. The response procedure directs the
operators to shut down the unloaded EDGs and place them in standby. The operators
chose to first place all three EDGs in manual, which makes them inoperable, and then
shut them down and restored to auto one by one. This resulted in all three EDGs
being inoperable for approximately two minutes. The licensee identified this condition
the following day during a routine supervisory review, and subsequently followed up with
the required 8-hour non-emergency report to the NRC for an unanalyzed condition.
The inspectors dispositioned the failure to comply with technical specifications as a
licensee identified violation in Section 4OA7 of this report.
No additional deficiencies were identified during the review of these Licensee Event
Reports supplemental revisions. This Licensee Event Report is closed.
These activities constitute completion of four event follow-up samples, as defined in Inspection
Procedure 71153.
4OA6 Meetings, Including Exit
Exit Meeting Summary
On November 21, 2013, the inspectors presented the results of the onsite inspection of the
licensees emergency preparedness program to Mr. T. Baldwin, Manager, Regulatory Services,
and other members of the licensees staff. The licensee acknowledged the issues presented.
The inspectors asked the licensee whether any materials examined during the inspection should
be considered proprietary. No proprietary information was identified.
On January 16, 2014, the inspectors presented the inspection results to Mr. E. Halpin, Senior
Vice President and Chief Nuclear Officer, and other members of the licensee staff. The licensee
acknowledged the issues presented. The inspector asked the licensee whether any materials
examined during the inspection should be considered proprietary. No proprietary information
was identified.
On February 7, 2014, the inspectors presented additional information regarding the inspection
results to Mr. E. Halpin, Senior Vice President and Chief Nuclear Officer, and other members of
the licensee staff. The licensee acknowledged the issues presented. The inspector asked the
licensee whether any materials examined during the inspection should be considered
proprietary. No proprietary information was identified.
4OA7 Licensee-Identified Violations
The following violation of very low safety significance (Green) was identified by the licensee and
is a violation of NRC requirements which meets the criteria of the NRC Enforcement Policy for
being dispositioned as a non-cited violation.
Technical Specification 3.8.1, Condition I, states, when two or more Emergency Diesel
Generators (EDGs) and one or more required offsite circuits are inoperable, the required
action is to enter Limiting Condition for Operation (LCO) 3.0.3, which requires a unit
shutdown initiated within one hour. Contrary to this, on June 23, 2013, following a loss
of 230kV offsite power, Unit 1 control room operators did not enter LCO 3.0.3 when they
simultaneously made all three EDGs inoperable by placing them all in manual. When
- 29 -
230kV startup power to the site was lost due to an electrical fault on the grid, all diesel
generators started automatically, as designed. The response procedure directs the
operators to shut down the unloaded EDGs and place them in standby. The operators
chose to first place all three EDGs in manual, which makes them inoperable, and then
shut them down and restored to auto one by one. This resulted in all three EDGs
being inoperable for approximately two minutes. The licensee identified this condition
the following day during a routine supervisory review and subsequently followed up with
the required 8-hour non-emergency report to the NRC for an unanalyzed condition. The
performance deficiency was more than minor because it was associated with operating
equipment lineup area of the configuration control attribute of the mitigating systems
cornerstone and affected the cornerstone objective to ensure the availability, reliability,
and capability of systems that respond to initiating events to prevent undesirable
consequences (i.e., core damage). In accordance with IMC 0609 Appendix A, Exhibit 2,
Mitigating Systems Screening Questions, this violation did not require a detailed risk
evaluation because it did not represent an actual loss of diesel generator function for
greater than the Technical Specification allowed outage time, and the risk-significant
function was not lost, even though the design basis start would not have occurred.
Therefore, this violation was of very low safety significance (Green). The licensee
entered the issue into the corrective action program as Notification 50570582.
Corrective actions included implementing more stringent requirements for supervisory
oversight of plant manipulations and modifying the response procedure to specify
sequential steps for placing EDGs in manual one at a time when securing.
A-1
Attachment
SUPPLEMENTAL INFORMATION
KEY POINTS OF CONTACT
Licensee Personnel
B. Allen, Site Vice President
J. Arhar, Supervisor, Engineering
S. Baker, Manager, Engineering
T. Baldwin, Manager, Regulatory Services
A. Bates, Director, Engineering Services
K. Bych, Manager, Engineering
S. Dunlap, Supervisor, Engineering
J. Fledderman, Director, Strategic Projects
P. Gerfen, Senior Manager
P. Gerfas, Assistant Director, Station Director
M. Gibbons, Acting Director, Work Control
M. Ginn, Manager, Emergency Planning
D. Gouveia, Manager, Operations
E. Halpin, Chief Nuclear Officer
D. Hardesty, Senior Engineer
J. Hinds, Director, Quality Verification
T. Irving, Manager, Radiation Protection
J. Kang, Engineer, Mechanical Systems Engineering
T. King, Director, Nuclear Work Management
A. Lin, Engineering
J. MacIntyre, Director, Maintenance Services
M. McCoy, NRC Interface, Regulatory Services
J. Nimick, Director, Operations Services
G. Porter, Senior Engineer
J. Salazar, System Engineer
L. Sewell, Supervisor, Radiation Protection
D. Shippey, ALARA Supervisor, Radiation Protection
R. Simmons, Manager, Electrical Maintenance
D. Stermer, Manager, Operation
M. Stevens, Associate, Quality Verification
S. Stoffel, Supervisor, Dosimetry
J. Summy, Senior Director, Engineering and Projects
L. Walter, Station Support
J. Welsch, Station Director R. West, Manager, ICE Systems
E. Wessel, Chemical Engineer, Chemistry
M. Wright, Manager, Mechanical Systems Engineering
A-2
LIST OF ITEMS OPENED, CLOSED, AND DISCUSSED
Opened 05000275/2013005-01
Procedures for Recommending Protective Actions for Members
of the Public on the Pacific Ocean (Section 1EP5)
Opened and Closed 05000323/2013005-02
NCV Reactor Trip due to a Lightning Arrester Flashover
(Section 4OA3.1)05000275/2013005-03
Auxiliary Feedwater Actuation Due to a Main Feedwater Pump
Trip (Section 4OA3.2)05000275/2012008-04
NCV Loss of Control Room Ventilation System due to Inadequate
Design Control (Section 4OA3.3)
Closed
05000323/2-2013-005-
01
LER Unit 2 Reactor Trip due to Lightning Arrester Flashover
(Section 4OA3.1)
05000275/1-2013-007-
00
LER Auxiliary Feedwater Actuation Due to a Main Feedwater Pump
Trip (Section 4OA3.2)
05000275; 05000323/
1-2012-008-00
LER Loss of Control Room Ventilation System due to Inadequate
Design Control (Section 4OA3.3)
05000275/1-2013-004-
00
LER All Three Unit 1 Emergency Diesel Generators Momentarily
Inoperable (Section 4OA3.4)
LIST OF DOCUMENTS REVIEWED
Section 1R01: Adverse Weather Protection
Procedures
Number
Title
Revision
OP J-2
Off-site Power Sources
9
Drawings
Number
Title
Revision
502110
500/230/25/12/4kV Systems
19
A-3
Section 1R04: Equipment Alignment
Procedures
Number
Title
Revision
OP J-6B:II-A
Diesel Generator 2-2 Alignment Checklist
0
OP J-6B:II-A
Diesel Generator 2-2 Alignment Checklist
0
OM6.ID13
Safety at Heights: Fall Protection, Ladder Safety, Working
Under Suspended Loads
18
OP D-1:II
Auxiliary Feedwater System - Alignment Checklist
0
Drawings
Number
Title
102014
Piping Schematic-Somponent Cooling Water System
Section 1R05: Fire Protection
Procedures
Number
Title
Revision
STP M-70C
Inspection of ECG Doors
24
STP M-39A1
U1 & 2, Routine Surveillance Test of Diesel Generator 1-1
(2-1) Room Carbon Dioxide Fire System Operation
16
DCM S-18
Fire Protection System
13B
OM8.ID4
Control of Flammable and Combustible Materials
20
OM8.ID1
Fire Loss Prevention
24
ECG 18.7
Fire Rated Assemblies
10
Drawings
Number
Title
Revision
111906
Units 1 and 2 Fire Drawings, Sheets 1-32
6
Section 1R06: Flood Protection Measures
Work Orders
64079046
64065780
A-4
Section 1R07: Heat Sink Performance
Procedures
Number
Title
Revision
STP M-51
Routine Surveillance Test of Containment Fan Cooler
Units
January 20, 2013
STP M-51
Routine Surveillance Test of Containment Fan Cooler
Units
March 10, 2013
STP M-93A
Refueling Interval Surveillance - Containment Fan
Cooler
March 13, 2013
Notifications
50592355
Section 1R11: Licensed Operator Requalification Program and Licensed Operator
Performance
Procedures
Number
Title
Revision
OP.1DC10
Conduct of Operations
39
Lesson R133S1
Fire in 480V Bus with Loss of Component Cooling
Water Flow to Reactor Coolant Pumps
1a
CP M-6
Fire
34
OP AP-11
Malfunction of Component Cooling Water System
30
EOP E-0
Reactor Trip or Safety Injection
43
Section 1R12: Maintenance Effectiveness
Miscellaneous
Title
Revision
Radiation Monitoring System Reliability and Availability October 29, 2013
Section 1R13: Maintenance Risk Assessments and Emergent Work Control
Procedures
Number
Title
Revision
MA1.DC11
230kV Bare Hand Removal and Installation Drops
October 10, 2013
A-5
Notifications
50578562
Section 1R15: Operability Determinations and Functionality Assessments
Procedures
Number
Title
Revision
OM7.ID12
27
OM7.ID13
Technical Evaluations
3
EOP E-2
Faulted Steam Generator Isolation
21
STP V-3P6A
Exercising Valves LCV-110 and LCV-111 Auxiliary
Feedwater Pump Discharge
24
STP P-AFW-12
Routine Surveillance Test of Motor-Driven Auxiliary
Feedwater Pump
18
STP I-92A
AMSAC Functional Test
7
STP I-92A
AMSAC Functional Test
8
STP M-21-A1
Emergency Diesel Generator Functional Test
95
STP M-9B
Diesel Engine Generator Routine Surveillance Test
94
Notifications
50314416
50587512
50507137
50587869
50314416
A0662030
A0692213
A0735701
A0671415
A0479517
50577766
50577917
50572400
50573100
50572174
50595324
50591862
50594028
50594186
50595251
50596161
50596125
50590178
5058999
Section 1R19: Post-Maintenance Testing
Procedures
Number
Title
Revision
STP M-9A
Diesel Engine Generator Routine Surveillance Test
94
STP M-9B
Diesel Engine Generator Routine Surveillance Test
94
STP P-AFW-22
Routine Surveillance Test of Motor-Driven Auxiliary
Feedwater Pump 2-2
17
A-6
Work Orders
64103356
60052907
60053052
60053529
64045245
64085882
60056781
64050757
64052107
64080841
64089790
64089802
64091605
64103362
64057674
50439378
Section 1R22: Surveillance Testing
Procedures
Number
Title
Revision
STP V-3P6A
Exercising Valves LCV-110 and LCV-111 Auxiliary
Feedwater Pump Discharge
24
STP P-AFW-12
Routine Surveillance Test of Motor-Driven Auxiliary
Feedwater Pump
18
STP I-92A
AMSAC Functional Test
7
STP I-92A
AMSAC Functional Test
8
Notifications
50587512
50507137
50587869
50314416
Section 1EP2: Alert and Notification System Testing
Procedures
Number
Title
Revision
EP MT-43
Early Warning System And Maintenance
11
Miscellaneous
Number
Title
Revision
Alert and Notification Design Report
0
Alert and Notification Design Report
1
P000129
Testing the MK 831DT Battery with the SOC 140
Battery Tester
A
A-7
Section 1EP3: Emergency Response Organization Staffing and Augmentation System
Procedure
Number
Title
Revision
EP EF-1
Activation And Operation Of The Technical Support
Center
44
EP EF-2
Activation And Operation Of The Operational Support
Center
33
EP EF-3
Activation And Operation Of The Emergency
Operations Facility
37
Section 1EP4: Emergency Action Level and Emergency Plan Changes
Procedure
Number
Title
Revision
EP, Appendix F
ERO On-Shift Staffing Analysis Report
4.00A
EP, Appendix D,
Category S
System Malfunction
4.01A
EP, Section 7
Emergency Facilities and Equipment
4.18
Section 1EP5: Maintenance of Emergency Preparedness
Procedure
Number
Title
Revision
AWP EP-007
Updating Letters of Agreement
0
EP EF-11
Operation of Alternate Emergency Response
Facilities
0
EP EF-9
Backup Emergency Response Facilities
11
EP G-1
Emergency Classification and Emergency Plan
Activation
43
EP G-3
Notification of Off-Site Organizations
0
EP G-3
Notification of Offsite Organizations
2
EP G-3
Notification of Off-Site Agencies and Emergency
Response Organization Personnel
39
EP G-3
Notification of Off-Site Agencies
40
EP G-3
Emergency Notification of Off-Site Agencies
54B
EP G-4
Assembly and Accountability
26
A-8
Procedure
Number
Title
Revision
EP G-5
Evacuation of Non-Essential Site Personnel
14
EP MT-27
Technical Support Center and Alternate Facility
Location
13
EP MT-28
Operational Support Center and Alternate Facility
Location
11
EP MT-29
Emergency Operations Facility (EOF)
10
EP RB-10
Protective Action Recommendations
10
EP RB-10
Protective Action Recommendations
16
EP RB-3
Stable Iodine Thyroid Blocking
7
OM10
2
OM10.DC1
Emergency Preparedness Drills and Exercises
6
OM10.DC2
Emergency Response Organization On-Call
6
OM10.DC3
Emergency Response Facilities, Equipment, and
Resources
6
OM10.ID2
Emergency Plan Revision and Review
11
OM10.ID4
Emergency Response Organization Management
12
OM7.ID1
Problem Identification and Resolution
43
OP1.DC17
Control of Equip Required by Technical
Specifications or Designated Programs
27
OP1.DC37
Plant Logs
49
XI1.ID2
Regulatory Reporting Requirements and Reporting
Process
38
Miscellaneous
Number
Title
Revision
Cal OES - Emergency Planning Zones for Serious
Nuclear Power Plant Accidents
4
PSS25
USCG - DCPP Emergency Response
November 2007
SOP III.01
San Luis Obispo County - Emergency Services
Director
October 2012
SOP III.25
San Luis Obispo County - United States Coast Guard
June 2013
A-9
Number
Title
Revision
SOP III.44
San Luis Obispo County - Port San Luis Harbor
District
September 2012
Emergency Plan Implementing Procedure Update
March 5, 2003
FN120390032
Emergency Preparedness Program Audit
May 3, 2012
FN123390018
Emergency Preparedness Program Audit
February 13, 2013
SAPN50527030
2013 DCPP Baseline Inspection Readiness
Assessment Report
October 18, 2013
Condition Reports
50390230
50392157
50420772
50422636
50422848
50426267
50426528
50427067
50429569
50439297
50439409
50441513
50454155
50457490
50459012
50463112
50468358
50480569
50507869
50508628
50510467
50511677
50522732
50523461
50531921
50531922
50532391
50536699
50542191
50557886
50560263
50562023
50569770
50572410
50573151
50583556
50584094
50593750
50595533
Section 4OA1: Performance Indicator Verification
Procedure
Number
Title
Revision
AWP EP-001
Emergency Preparedness Performance Indicators
16
XI1.DC1
Collection and Submittal of NRC Performance
Indicators
12
STP R-10C
Reactor Coolant System Water Inventory Balance
44
A-10
Section 4OA2: Problem Identification and Resolution
Procedures
Number
Title
Revision
AD4.ID3
SISIP Housekeeping Activities
12
Seismically Induced Systems Interaction Manual
10
AD7.ID2
Daily Notification Review Team and Standard Plant
Priority Assignment Scheme
20
AD7.ID12
Work Management Process
3
Notifications
50494799
50463051
50299740
50499634
50572174
50587627
50572355
50577917
50572400
50573100
50588799
50587467
50592711
50595324
50600007
50591862
50592561
50560387
50592561
50560826
50583459
50583562
Section 4OA3: Follow-up of Events and Notices of Enforcement Discretion
Notifications
50572400
50573100
50572800
Section 4OA7: Licensee-Identified Violations
Notifications
50570582