Information Notice 2018-04, Operating Experience Regarding Failure of Operators to Trip the Plant When Experiencing Unstable Conditions: Difference between revisions

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{{#Wiki_filter:UNITED STATES
{{#Wiki_filter:ML17269A262 UNITED STATES


NUCLEAR REGULATORY COMMISSION
NUCLEAR REGULATORY COMMISSION
Line 23: Line 23:
OFFICE OF NEW REACTORS
OFFICE OF NEW REACTORS


WASHINGTON, DC 20555-0001 February 26, 2018 NRC INFORMATION NOTICE 2018-04:               OPERATING EXPERIENCE REGARDING FAILURE
WASHINGTON, DC 20555-0001  
 
February 26, 2018  
 
NRC INFORMATION NOTICE 2018-04:  
OPERATING EXPERIENCE REGARDING FAILURE


OF OPERATORS TO TRIP THE PLANT WHEN
OF OPERATORS TO TRIP THE PLANT WHEN
Line 32: Line 37:
All holders of an operating license for a non-power reactor (research reactor, test reactor, or
All holders of an operating license for a non-power reactor (research reactor, test reactor, or


critical assembly) under Title 10 of the Code of Federal Regulations (10 CFR) Part 50,
critical assembly) under Title 10 of the Code of Federal Regulations (10 CFR) Part 50,  
Domestic Licensing of Production and Utilization Facilities, except those who have
Domestic Licensing of Production and Utilization Facilities, except those who have


Line 52: Line 57:
addressees of several reactor events during which operators failed to take timely action to place
addressees of several reactor events during which operators failed to take timely action to place


the plant in a stable condition. It is expected that recipients will review the information for
the plant in a stable condition. It is expected that recipients will review the information for


applicability to their facilities and consider actions, as appropriate, to avoid similar problems.
applicability to their facilities and consider actions, as appropriate, to avoid similar problems.
Line 61: Line 66:


==DESCRIPTION OF CIRCUMSTANCES==
==DESCRIPTION OF CIRCUMSTANCES==
Fermi, Unit 2


===Fermi, Unit 2===
On March 19, 2015, Fermi, Unit 2 (Fermi) experienced a closed cooling water leak within
On March 19, 2015, Fermi, Unit 2 (Fermi) experienced a closed cooling water leak within


primary containment, causing operators to trip one of the two reactor recirculation pumps. The
primary containment, causing operators to trip one of the two reactor recirculation pumps. The


resulting reactor conditions (45 percent recirculation flow, 61 percent reactor power) placed the
resulting reactor conditions (45 percent recirculation flow, 61 percent reactor power) placed the


plant in the exit region of the power-to-flow map. This required the licensee to place the plant
plant in the exit region of the power-to-flow map. This required the licensee to place the plant


in a more stable configuration (either by raising flow or lowering power) to avoid
in a more stable configuration (either by raising flow or lowering power) to avoid
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thermal-hydraulic instability (THI) and the oscillating flux distributions this can cause within the
thermal-hydraulic instability (THI) and the oscillating flux distributions this can cause within the


active fuel region. Control room operators entered the appropriate abnormal operating
active fuel region. Control room operators entered the appropriate abnormal operating


procedures (AOPs) for the plant conditions, but failed to prioritize the inserting of rods to quickly
procedures (AOPs) for the plant conditions, but failed to prioritize the inserting of rods to quickly


lower power during the trip of the recirculation pump. As the transient progressed, the expected
lower power during the trip of the recirculation pump. As the transient progressed, the expected
 
loss of feedwater heating caused a 12 percent power increase over approximately a 10-minute


ML17269A262 period. This drove the reactor further into the exit region of the power-to-flow map, and while
loss of feedwater heating caused a 12 percent power increase over approximately a 10-minute period. This drove the reactor further into the exit region of the power-to-flow map, and while


operators were initiating actions to insert control rods, two channels on the oscillation power
operators were initiating actions to insert control rods, two channels on the oscillation power
Line 91: Line 94:
When the OPRM system was first made operable at Fermi in May 2000, three AOPs were
When the OPRM system was first made operable at Fermi in May 2000, three AOPs were


revised. These AOPs were "Loss of Feedwater Heating," "Recirculation Pump Trip," and "Jet
revised. These AOPs were "Loss of Feedwater Heating," "Recirculation Pump Trip," and "Jet


Pump Failure." These revisions incorporated the functions of the OPRM system, but removed
Pump Failure." These revisions incorporated the functions of the OPRM system, but removed


important control room operator actions from the procedures. In all cases, the requirement to
important control room operator actions from the procedures. In all cases, the requirement to


monitor for THI through the selection of control rods was removed, as was the statement to
monitor for THI through the selection of control rods was removed, as was the statement to


place the reactor mode switch in "shutdown" if THI was observed. The bases for the procedure
place the reactor mode switch in "shutdown" if THI was observed. The bases for the procedure


changes reflected the licensees belief of the superior capability of the newly installed electronic
changes reflected the licensees belief of the superior capability of the newly installed electronic
Line 109: Line 112:
licensed operator training, which in turn affected the ability to maneuver the plant when
licensed operator training, which in turn affected the ability to maneuver the plant when


confronted with plant conditions susceptible to THI. Post-trip review of operator actions during
confronted with plant conditions susceptible to THI. Post-trip review of operator actions during


this event found a lack of timely operator response during power oscillations caused by THI.
this event found a lack of timely operator response during power oscillations caused by THI.


Further details are available in Fermi Licensee Event Report 05000341/2015-003, dated May 5,
Further details are available in Fermi Licensee Event Report 05000341/2015-003, dated May 5,  
2015 (Agencywide Documents Access and Management System (ADAMS) Accession
2015 (Agencywide Documents Access and Management System (ADAMS) Accession


Line 120: Line 123:
November 5, 2015 (ADAMS Accession No. ML15309A680).
November 5, 2015 (ADAMS Accession No. ML15309A680).


===Grand Gulf Nuclear Station, Unit 1===
Grand Gulf Nuclear Station, Unit 1  
 
On June 17, 2016, Grand Gulf Nuclear Station, Unit 1 (Grand Gulf) was operating at
On June 17, 2016, Grand Gulf Nuclear Station, Unit 1 (Grand Gulf) was operating at


approximately 65 percent rated thermal power while performing surveillance testing on the
approximately 65 percent rated thermal power while performing surveillance testing on the


turbine stop valves. With the B turbine stop valve shut as part of the surveillance procedure, the D turbine stop valve unexpectedly shut. While operators attempted to reset the B turbine
turbine stop valves. With the B turbine stop valve shut as part of the surveillance procedure, the D turbine stop valve unexpectedly shut. While operators attempted to reset the B turbine


stop valve, the A and C turbine control valves were challenged in their ability to provide the
stop valve, the A and C turbine control valves were challenged in their ability to provide the
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required control of turbine pressure and reactor pressure, resulting in oscillations of turbine
required control of turbine pressure and reactor pressure, resulting in oscillations of turbine


pressure, and hence reactor pressure and reactor power. Control room operators, including
pressure, and hence reactor pressure and reactor power. Control room operators, including


managers in oversight roles, focused on the turbine control valve movements and possible
managers in oversight roles, focused on the turbine control valve movements and possible
Line 137: Line 141:
recovery actions, and failed to appreciate the impact that the turbine control valve fluctuations
recovery actions, and failed to appreciate the impact that the turbine control valve fluctuations


and reset efforts were having on reactivity. Reactor power oscillations of 10-20 percent were
and reset efforts were having on reactivity. Reactor power oscillations of 10-20 percent were


seen over the course of the next 42 minutes, with a maximum recorded power of 87 percent
seen over the course of the next 42 minutes, with a maximum recorded power of 87 percent
Line 143: Line 147:
before an automatic reactor scram occurred on an OPRM trip.
before an automatic reactor scram occurred on an OPRM trip.


Operators had recently received training on the Fermi event discussed above. The training
Operators had recently received training on the Fermi event discussed above. The training


emphasized the need to scram the reactor in the event that THI resulted in reactor power
emphasized the need to scram the reactor in the event that THI resulted in reactor power


oscillations. However, Grand Gulf lacked a procedure for responding to malfunctions of the
oscillations. However, Grand Gulf lacked a procedure for responding to malfunctions of the


reactor pressure control system, and after verifying that the power oscillations they were seeing
reactor pressure control system, and after verifying that the power oscillations they were seeing
Line 167: Line 171:
Accession No. ML16315A372).
Accession No. ML16315A372).


===Joseph M. Farley Nuclear Plant, Unit 1===
Joseph M. Farley Nuclear Plant, Unit 1  
 
On October 1, 2016, with the Joseph M. Farley Nuclear Plant, Unit 1 (Farley) operating at
On October 1, 2016, with the Joseph M. Farley Nuclear Plant, Unit 1 (Farley) operating at


Line 176: Line 181:
intermediate position, including a main control board annunciator for low air pressure for the
intermediate position, including a main control board annunciator for low air pressure for the


valve. In accordance with the annunciator response procedure, operators attempted to
valve. In accordance with the annunciator response procedure, operators attempted to


recharge the accumulator by moving the switch for the valve to open, but the indications
recharge the accumulator by moving the switch for the valve to open, but the indications
Line 184: Line 189:
The next step of the procedure directed a manual reactor trip in order to reduce the challenge to
The next step of the procedure directed a manual reactor trip in order to reduce the challenge to


the plant that would result from the MSIV failing shut. Instead, operators attempted to isolate
the plant that would result from the MSIV failing shut. Instead, operators attempted to isolate


the leaking test solenoid valve that was causing the loss of air pressure and restore the MSIV to
the leaking test solenoid valve that was causing the loss of air pressure and restore the MSIV to


the full open position. Prior to performing the test valve isolation, and 37 minutes after
the full open position. Prior to performing the test valve isolation, and 37 minutes after


operators first received an alarm in the control room, the MSIV failed shut on loss of air
operators first received an alarm in the control room, the MSIV failed shut on loss of air


pressure. This resulted in an automatic reactor trip and a safety injection on low steam line
pressure. This resulted in an automatic reactor trip and a safety injection on low steam line


pressure (rate compensated) in the 1B and 1C steam lines, as expected for this event. Contrary
pressure (rate compensated) in the 1B and 1C steam lines, as expected for this event. Contrary


to procedural requirements, licensed senior reactor operators decided to maintain the reactor
to procedural requirements, licensed senior reactor operators decided to maintain the reactor


online while attempting to isolate the leak. Had operators followed the procedure and manually
online while attempting to isolate the leak. Had operators followed the procedure and manually


tripped the reactor, they could possibly have prevented the safety injection.
tripped the reactor, they could possibly have prevented the safety injection.
Line 223: Line 228:
This places increased emphasis on the importance of complete and accurate procedures to
This places increased emphasis on the importance of complete and accurate procedures to


guide operators through unfamiliar situations. Regulations in 10 CFR 50 Appendix B, Criterion
guide operators through unfamiliar situations. Regulations in 10 CFR 50 Appendix B, Criterion


V, Instructions, Procedures, and Drawings, as well as individual plant technical specifications, require licensees to maintain and adhere to quality procedures for activities affecting safety.
V, Instructions, Procedures, and Drawings, as well as individual plant technical specifications, require licensees to maintain and adhere to quality procedures for activities affecting safety.
Line 229: Line 234:
Regulatory Guide 1.33, Quality Assurance Program Requirements (Operation), provides a
Regulatory Guide 1.33, Quality Assurance Program Requirements (Operation), provides a


comprehensive list of systems, situations, and processes that might require quality procedures, as specified by the individual plant licensing basis. However, emergency operating procedures
comprehensive list of systems, situations, and processes that might require quality procedures, as specified by the individual plant licensing basis. However, emergency operating procedures


are symptom-driven and are not intended to cover every possible contingency. Regulatory
are symptom-driven and are not intended to cover every possible contingency. Regulatory


requirements for licensee training programs are structured to ensure that operators have a
requirements for licensee training programs are structured to ensure that operators have a
Line 241: Line 246:
condition. The events discussed in this IN involved operators misinterpreting procedures, failing to adhere
condition. The events discussed in this IN involved operators misinterpreting procedures, failing to adhere


to procedure requirements, or failing to recognize incomplete or faulty procedures. In each
to procedure requirements, or failing to recognize incomplete or faulty procedures. In each


case, the failure to maintain a conservative bias in the decision-making process left the reactor
case, the failure to maintain a conservative bias in the decision-making process left the reactor
Line 247: Line 252:
in an unstable condition for extended periods of time before automatic protective features
in an unstable condition for extended periods of time before automatic protective features


actuated, increasing the probability that a more significant event could occur. Industry operating
actuated, increasing the probability that a more significant event could occur. Industry operating


experience has shown the importance of diverse simulator scenarios that accurately represent
experience has shown the importance of diverse simulator scenarios that accurately represent


plant response while incorporating complex system interactions. By stressing procedure
plant response while incorporating complex system interactions. By stressing procedure


adherence and challenging critical thinking skills, these scenarios can improve operator
adherence and challenging critical thinking skills, these scenarios can improve operator
Line 260: Line 265:


==CONTACT==
==CONTACT==
This information notice requires no specific action or written response. Please direct any
This information notice requires no specific action or written response. Please direct any


questions about this matter to the technical contacts listed below or the appropriate Office of
questions about this matter to the technical contacts listed below or the appropriate Office of
Line 266: Line 271:
Nuclear Reactor Regulation (NRR) project manager.
Nuclear Reactor Regulation (NRR) project manager.


/RA/ (Paul G. Krohn for)                             /RA/
/RA/ (Paul G. Krohn for)  
Timothy J. McGinty, Director                 Christopher G. Miller, Director
 
/RA/  
 
Timothy J. McGinty, Director
 
Christopher G. Miller, Director
 
Division of Construction Inspection
 
Division of Inspection and Regional Support
 
and Operational Programs
 
Office of Nuclear Reactor Regulation
 
Office of New Reactors
 
Technical Contacts: Rebecca Sigmon, NRR
 
301-415-0895 E-mail:  Rebecca.Sigmon@nrc.gov


Division of Construction Inspection          Division of Inspection and Regional Support
Note:  NRC generic communications may be found on the NRC public Web site, https://www.nrc.gov, under NRC Library. NRC INFORMATION NOTICE 2018-04, OPERATING EXPERIENCE REGARDING FAILURE


and Operational Programs                      Office of Nuclear Reactor Regulation
OF OPERATORS TO TRIP THE PLANT WHEN EXPERIENCING UNSTABLE CONDITIONS,
DATE:  February 26, 2018


===Office of New Reactors===
ADAMS Accession Number: ML17269A262
Technical Contacts:   Rebecca Sigmon, NRR


301-415-0895 E-mail: Rebecca.Sigmon@nrc.gov
*via email


Note: NRC generic communications may be found on the NRC public Web site, https://www.nrc.gov, under NRC Library. NRC INFORMATION NOTICE 2018-04, OPERATING EXPERIENCE REGARDING FAILURE
TAC No. MG0173 OFFICE


OF OPERATORS TO TRIP THE PLANT WHEN EXPERIENCING UNSTABLE CONDITIONS,
TECH EDITOR*  
DATE: February 26, 2018 ADAMS Accession Number: ML17269A262                    *via email      TAC No. MG0173 OFFICE TECH EDITOR*   NRR/DIRS/IOEB/TR  NRR/DIRS/IOLB/BC    NRR/DIRS/IOEB/TR     NRR/DIRS/IEOB/BC
NRR/DIRS/IOEB/TR


NAME   JDougherty*     RSigmon*         NSalgado for       AIssa                RElliott
NRR/DIRS/IOLB/BC
 
NRR/DIRS/IOEB/TR
 
NRR/DIRS/IEOB/BC
 
NAME
 
JDougherty*  
RSigmon*  
NSalgado for


CCowdry
CCowdry


DATE   09/27/2017     10/25/2017       11/17/2017         11/29/2017           12/05/2017 OFFICE NRR/DIRS/IRGB/  NRR/DIRS/IRGB/LA  NRR/DIRS/IRGB/BC    NRO/DCIP/D            NRR/DIRS/D
AIssa
 
RElliott
 
DATE
 
09/27/2017  
10/25/2017  
11/17/2017  
11/29/2017  
12/05/2017 OFFICE


NRR/DIRS/IRGB/
PM
PM


NAME   TGovan         ELee             HChernoff           TMcGinty (PKrohn for) CMiller
NRR/DIRS/IRGB/LA
 
NRR/DIRS/IRGB/BC
 
NRO/DCIP/D
 
NRR/DIRS/D
 
NAME
 
TGovan
 
ELee
 
HChernoff
 
TMcGinty (PKrohn for)  
CMiller
 
DATE


DATE  12/05/2017     12/06/2017       02/06/2018         02/14/2018           02/26/2018 OFFICIAL RECORD COPY}}
12/05/2017  
12/06/2017  
02/06/2018  
02/14/2018  
02/26/2018 OFFICIAL RECORD COPY}}


{{Information notice-Nav}}
{{Information notice-Nav}}

Latest revision as of 09:10, 8 January 2025

Operating Experience Regarding Failure of Operators to Trip the Plant When Experiencing Unstable Conditions
ML17269A262
Person / Time
Issue date: 02/26/2018
From: Mcginty T, Chris Miller
Division of Construction Inspection and Operational Programs, Division of Inspection and Regional Support
To:
Govan T
References
TAC MG0173 IN 2018-04
Download: ML17269A262 (5)
v • d • e


ML17269A262 UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

OFFICE OF NEW REACTORS

WASHINGTON, DC 20555-0001

February 26, 2018

NRC INFORMATION NOTICE 2018-04:

OPERATING EXPERIENCE REGARDING FAILURE

OF OPERATORS TO TRIP THE PLANT WHEN

EXPERIENCING UNSTABLE CONDITIONS

ADDRESSEES

All holders of an operating license for a non-power reactor (research reactor, test reactor, or

critical assembly) under Title 10 of the Code of Federal Regulations (10 CFR) Part 50,

Domestic Licensing of Production and Utilization Facilities, except those who have

permanently ceased operations.

All holders of an operating license or construction permit for a nuclear power reactor under

10 CFR Part 50, Domestic Licensing of Production and Utilization Facilities, except those that

have permanently ceased operations and have certified that fuel has been permanently

removed from the reactor vessel.

All holders of and applicants for a combined license under 10 CFR Part 52, Licenses, Certifications, and Approvals for Nuclear Power Plants.

PURPOSE

The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice (IN) to inform

addressees of several reactor events during which operators failed to take timely action to place

the plant in a stable condition. It is expected that recipients will review the information for

applicability to their facilities and consider actions, as appropriate, to avoid similar problems.

However, suggestions contained in this IN are not NRC requirements; therefore, no specific

action or written response is required.

DESCRIPTION OF CIRCUMSTANCES

Fermi, Unit 2

On March 19, 2015, Fermi, Unit 2 (Fermi) experienced a closed cooling water leak within

primary containment, causing operators to trip one of the two reactor recirculation pumps. The

resulting reactor conditions (45 percent recirculation flow, 61 percent reactor power) placed the

plant in the exit region of the power-to-flow map. This required the licensee to place the plant

in a more stable configuration (either by raising flow or lowering power) to avoid

thermal-hydraulic instability (THI) and the oscillating flux distributions this can cause within the

active fuel region. Control room operators entered the appropriate abnormal operating

procedures (AOPs) for the plant conditions, but failed to prioritize the inserting of rods to quickly

lower power during the trip of the recirculation pump. As the transient progressed, the expected

loss of feedwater heating caused a 12 percent power increase over approximately a 10-minute period. This drove the reactor further into the exit region of the power-to-flow map, and while

operators were initiating actions to insert control rods, two channels on the oscillation power

range monitor (OPRM) system tripped, resulting in an automatic reactor scram.

When the OPRM system was first made operable at Fermi in May 2000, three AOPs were

revised. These AOPs were "Loss of Feedwater Heating," "Recirculation Pump Trip," and "Jet

Pump Failure." These revisions incorporated the functions of the OPRM system, but removed

important control room operator actions from the procedures. In all cases, the requirement to

monitor for THI through the selection of control rods was removed, as was the statement to

place the reactor mode switch in "shutdown" if THI was observed. The bases for the procedure

changes reflected the licensees belief of the superior capability of the newly installed electronic

OPRM system to detect and suppress neutron flux instability as compared to a human operator.

The procedure changes during implementation of the OPRM system negatively impacted

licensed operator training, which in turn affected the ability to maneuver the plant when

confronted with plant conditions susceptible to THI. Post-trip review of operator actions during

this event found a lack of timely operator response during power oscillations caused by THI.

Further details are available in Fermi Licensee Event Report 05000341/2015-003, dated May 5,

2015 (Agencywide Documents Access and Management System (ADAMS) Accession

No. ML15127A176) and in NRC Integrated Inspection Report 05000341/2015003, dated

November 5, 2015 (ADAMS Accession No. ML15309A680).

Grand Gulf Nuclear Station, Unit 1

On June 17, 2016, Grand Gulf Nuclear Station, Unit 1 (Grand Gulf) was operating at

approximately 65 percent rated thermal power while performing surveillance testing on the

turbine stop valves. With the B turbine stop valve shut as part of the surveillance procedure, the D turbine stop valve unexpectedly shut. While operators attempted to reset the B turbine

stop valve, the A and C turbine control valves were challenged in their ability to provide the

required control of turbine pressure and reactor pressure, resulting in oscillations of turbine

pressure, and hence reactor pressure and reactor power. Control room operators, including

managers in oversight roles, focused on the turbine control valve movements and possible

recovery actions, and failed to appreciate the impact that the turbine control valve fluctuations

and reset efforts were having on reactivity. Reactor power oscillations of 10-20 percent were

seen over the course of the next 42 minutes, with a maximum recorded power of 87 percent

before an automatic reactor scram occurred on an OPRM trip.

Operators had recently received training on the Fermi event discussed above. The training

emphasized the need to scram the reactor in the event that THI resulted in reactor power

oscillations. However, Grand Gulf lacked a procedure for responding to malfunctions of the

reactor pressure control system, and after verifying that the power oscillations they were seeing

were not the result of THI, the operators concluded that the guidance to insert a manual scram

did not apply.

Following the event, the licensee implemented a standing order that gave clear guidance on

how to address issues that cause oscillations and has since created an off-normal event

procedure for reactor pressure control system malfunctions.

Further details on this event can be found in Grand Gulf Licensee Event Report

05000416/2016-004-00, dated August 12, 2016 (ADAMS Accession No. ML16225A724) and in NRC Integrated Inspection Report 05000416/2016003, dated November 10, 2016 (ADAMS

Accession No. ML16315A372).

Joseph M. Farley Nuclear Plant, Unit 1

On October 1, 2016, with the Joseph M. Farley Nuclear Plant, Unit 1 (Farley) operating at

99 percent power, operators in the control room received indications that the 1A steam

generator main steam isolation valve (MSIV) had drifted off its backseat and was in an

intermediate position, including a main control board annunciator for low air pressure for the

valve. In accordance with the annunciator response procedure, operators attempted to

recharge the accumulator by moving the switch for the valve to open, but the indications

remained.

The next step of the procedure directed a manual reactor trip in order to reduce the challenge to

the plant that would result from the MSIV failing shut. Instead, operators attempted to isolate

the leaking test solenoid valve that was causing the loss of air pressure and restore the MSIV to

the full open position. Prior to performing the test valve isolation, and 37 minutes after

operators first received an alarm in the control room, the MSIV failed shut on loss of air

pressure. This resulted in an automatic reactor trip and a safety injection on low steam line

pressure (rate compensated) in the 1B and 1C steam lines, as expected for this event. Contrary

to procedural requirements, licensed senior reactor operators decided to maintain the reactor

online while attempting to isolate the leak. Had operators followed the procedure and manually

tripped the reactor, they could possibly have prevented the safety injection.

To address the issue, the licensee conducted simulator training for all crews emphasizing

procedure use and adherence standards, and took further steps to address gaps in operator

performance.

Additional information appears in Farley Licensee Event Report 05000348/2016-002-00, dated

November 30, 2016 (ADAMS Accession No. ML16335A450) and NRC Integrated Inspection

Report 05000348/2016004 and 05000364/2016004, dated January 17, 2017 (ADAMS

Accession No. ML17027A147).

DISCUSSION

Since the average nuclear power plant now spends over 90 percent of its time online, operators

have less experience dealing with transients, startup, and shutdown operations than in the past.

This places increased emphasis on the importance of complete and accurate procedures to

guide operators through unfamiliar situations. Regulations in 10 CFR 50 Appendix B, Criterion

V, Instructions, Procedures, and Drawings, as well as individual plant technical specifications, require licensees to maintain and adhere to quality procedures for activities affecting safety.

Regulatory Guide 1.33, Quality Assurance Program Requirements (Operation), provides a

comprehensive list of systems, situations, and processes that might require quality procedures, as specified by the individual plant licensing basis. However, emergency operating procedures

are symptom-driven and are not intended to cover every possible contingency. Regulatory

requirements for licensee training programs are structured to ensure that operators have a

thorough understanding of integrated plant operations and system interactions so that they can

respond appropriately to events not anticipated by procedures to place the plant in a safe

condition. The events discussed in this IN involved operators misinterpreting procedures, failing to adhere

to procedure requirements, or failing to recognize incomplete or faulty procedures. In each

case, the failure to maintain a conservative bias in the decision-making process left the reactor

in an unstable condition for extended periods of time before automatic protective features

actuated, increasing the probability that a more significant event could occur. Industry operating

experience has shown the importance of diverse simulator scenarios that accurately represent

plant response while incorporating complex system interactions. By stressing procedure

adherence and challenging critical thinking skills, these scenarios can improve operator

understanding of event consequences and the actions necessary to mitigate those

consequences.

CONTACT

This information notice requires no specific action or written response. Please direct any

questions about this matter to the technical contacts listed below or the appropriate Office of

Nuclear Reactor Regulation (NRR) project manager.

/RA/ (Paul G. Krohn for)

/RA/

Timothy J. McGinty, Director

Christopher G. Miller, Director

Division of Construction Inspection

Division of Inspection and Regional Support

and Operational Programs

Office of Nuclear Reactor Regulation

Office of New Reactors

Technical Contacts: Rebecca Sigmon, NRR

301-415-0895 E-mail: Rebecca.Sigmon@nrc.gov

Note: NRC generic communications may be found on the NRC public Web site, https://www.nrc.gov, under NRC Library. NRC INFORMATION NOTICE 2018-04, OPERATING EXPERIENCE REGARDING FAILURE

OF OPERATORS TO TRIP THE PLANT WHEN EXPERIENCING UNSTABLE CONDITIONS,

DATE: February 26, 2018

ADAMS Accession Number: ML17269A262

  • via email

TAC No. MG0173 OFFICE

TECH EDITOR*

NRR/DIRS/IOEB/TR

NRR/DIRS/IOLB/BC

NRR/DIRS/IOEB/TR

NRR/DIRS/IEOB/BC

NAME

JDougherty*

RSigmon*

NSalgado for

CCowdry

AIssa

RElliott

DATE

09/27/2017

10/25/2017

11/17/2017

11/29/2017

12/05/2017 OFFICE

NRR/DIRS/IRGB/

PM

NRR/DIRS/IRGB/LA

NRR/DIRS/IRGB/BC

NRO/DCIP/D

NRR/DIRS/D

NAME

TGovan

ELee

HChernoff

TMcGinty (PKrohn for)

CMiller

DATE

12/05/2017

12/06/2017

02/06/2018

02/14/2018

02/26/2018 OFFICIAL RECORD COPY


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