Jaewhan KimRisk and Environmental Safety Research

Division, KAERI

U.S. NRC HRA Data Workshop, 14-15 March, 2019, NRC HQ

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Introduction

Status on FLEX/MACST* HRA› Preliminary Study on HRA for a Task deploying Portable Equipment in an

ELAP Event › A Guideline for HRA of Mitigation Strategies using Portable Equipment

(DRAFT; Internal and Seismic)

Status on SAMG HRA› Qualitative Information Analysis for SAM Strategy, Situation, and EROs› Case Study for a TLOCCW scenario

Future Plans

* FLEX: U.S. Flexible Coping Strategies for Beyond-Design-Basis External EventsMACST: Korean Multi-barrier Accident Coping Strategies

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• Applicants shall submit the Accident Management Plan (AMP) as one of OL application documents

– Scope of AMP: Design-Basis Accidents, Multiple failures, BDBEEs including both Natural or Man-made events, Severe Accidents

• Evaluation of Accident Management Capability: Both Deterministic and Probabilistic Approaches shall be used

– Risk Targets [1]

ü The prompt fatality or cancer fatality risks of the population near a NPP from the accident should not exceed 0.1% of the sum of risks resulting from all other causes; or the equivalent performance goals for the prompt fatality and the caner fatality risks should be satisfied.

ü The sum of frequencies for the accident scenarios in which the amount of Cs-137 release exceeds 100 TBq should be less than 1.0E-06/ry.

– PSA results should be utilized to enhance the capability in prevention and mitigation of severe accidents

[1] Kim, D., General status and current rulemakings on PSA, Information Exchange Meeting on Multi-unit PSA, Canada, 2017.

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[1] Kim J., Cho J., Technical challenges in modeling human and organizational actions in severe accident conditions for Level 2 PSA, Reliability Engineering and System Safety, https://doi.org/10.1016/j.ress.2018.08.003.

Status on the FLEX/MACST HRA

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§ Task: Deploy and Install the 4.16kV Portable Generator to Supply Electrical Power to Essential Systems and MCR Instrumentation

§ Ways of Use of Portable Equipment▪ Case_1: Pre-staging of portable equipment

(connection and startup required)▪ Case_2: Deploying the equipment by the initial

emergency response team▪ Case_3: Deploying the equipment by the off-

site emergency response team (called from the off-site)

§ Preliminary Human Reliability Analysis▪ Detailed Task/Activity Analysis

▪ Error Modes and Performance Shaping Factors, Recovery Potentials, and

▪ HEP Estimation using Currently Available HRA Method and Data (i.e., EPRI internal/external HRAs)

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§ Task Flow and Activities associated with Deploying a Portable Generator▪ Situation Assessment and Planning for ELAP Event based on EOP (MCR)▪ Direction/Instruction of Deploying Portable Generator to Local Emergency Response Team (via

communication system or direct oral communication) (MCR, Local Staff)▪ Preparation of Essential Equipment/Tools/Components (e.g., Cable, Lights, Tools, etc.) (Local Staff)▪ Selection/Loading, Transportation, and Unloading of the Portable Equipment (Local Staff)▪ Installation/Connection of the Portable Equipment (i.e., cables and electrical buses) (Local Staff)▪ (Report to the MCR on the Completion of Installation/Connection)▪ Startup of the Portable Generator and Closing the Breaker to Supply Electrical Power (Local Staff)▪ (Check by the MCR and Follow-up Actions) (MCR)

MCR Local Emergency Staff Situation Assessment and Planning for ELAP

Direction/Instruction of Deploying Portable Generator

Preparation of Essential Equipment/Tools/Components

Selection/Loading, Transportation, and Unloading of the Portable Equipment Installation/Connection of the Portable Equipment (Report to MCR)Startup of the Portable Generator and Closing the Breaker

Check by the MCR and Follow-up Actions

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§ Decomposition of the Task into Basic Task Activities:▪ Diagnosis, Decision-making, and Direction/Instruction▪ Preparation of Equipment/Tools/Components▪ Loading, Transportation, and Unloading▪ Installation, and Startup/Alignment/Closing the Break▪ Coordination between MCR and Local Staff (Check and Follow-up Actions)

§ Estimation of HEP for Each of Basic Task Activities▪ Diagnosis, Decision-making, and Direction/Instruction

• Situation Assessment and Planning based on EOP, and Delivery of Direction and Instruction• Decision Delay may be possible for some cases/situations -> Needs to be considered in timing analysis

• Method for Estimation of HEPs: Max (K-HRA, CBDTM)• K-HRA (i.e., Korean Standard HRA Method) Diagnosis Error based on Time Available for Diagnosis• CBDTM (i.e., Cause-Based Decision Tree Method by EPRI)

▪ Preparation of Equipment/Tools/Components• Use of K-HRA Execution Error

• Decomposition into Equipment/Tools/Components, Storage Places, and Responsible Personnel• HEP = ∑ {Task Type, Stress Level}i * RFPi

- Task Type = ‘Step by Step’; Stress Level = ‘Optimal’, ‘Moderately High’, ‘Very High’ and ‘Extremely High’ - Recovery Failure Probability (RFP) = 0.05 if time for error recovery is sufficient

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§ Estimation of HEPs for Basic Task Activities (cont.)▪ Loading, Transportation, and Unloading

• HEP for this task activities is neglected for internal events; But for external events the intensity of external events needs to be considered for feasibility analysis as well as for the potential for debris or obstructions along the travel path.

• If there is the potential for debris or obstructions along the travel path, the methods, staffing, and time for removing the debris or obstructions needs to be identified/estimated in feasibility and detailed analysis

▪ Installation (Cable/Hose), and Startup/Alignment/Closing the Break• These Activities are Considered to be a Series of Connected Actions• Concerted Actions between MCR and Local Staff are Expected; Potential for Error Recovery by the MCR is

Considered.• Basic_HEP = 2.0E-2 for Normal Condition is Used on the basis of the following error potentials:- Connection Error (THERP Table 20-12 Item 13; Improperly mate a connector (this includes failures to

seat connectors completely and failure to test locking features of connectors for proper engagement) => 1.3E-02 (mean)

- Omission Error (THERP Table 20-7b Item 4; Omission of item when procedures without checkoff provisions are used, or when available checkoff provisions are incorrectly used. Long list > 10 items) => 4.2E-03 (mean)

- Selection Error (THERP Table 20-12 Item 2 or 12; Select wrong control on a panel from an array of similar-appearing controls identified by labels only (mean) => 3.8E-03 (mean)

• Adjustment of Basic_HEP by Stress Level, e.g., HEP = 0.04 for MH, 0.08 for VH, and 0.2 for EH.• Recovery Failure Probability (RFP) for Check by MCR = 0.05 (refer to K-HRA)

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Work Flow / Activity Error Modes (IE + EE) Factors to be considered for EEs (esp., for Seismic Event)

• Diagnosis and Planning of the Event

• Task Order to Local emergency response team (via communication system or direct oral communication)

• Omission of Task Initiation • Error in Delivery of Task Order (wrong

communication) • Loss of Communication System: Delay in

Delivering Orders and Getting Feedbacks • Loss/Damage of/to Emergency Personnel

(both on-site and off-site)

• Impact on the Communication

System • Impact on Personnel Availability

(e.g., Loss/Impairment) • Preparation of essential

equipment/tools/ components • Omission of preparing essential

tools/components • Failure to make access to the

equipment/tools/components

• Impact on Equipment Storage

Facility and Travel Paths • Selection and Loading of the

equipment • Selection/loading of wrong equipment

from the storage facility • Failure to load the equipment due to an

EE

• Impact on the loading when it is

performed outside of the facility

• Transportation and Unloading of the equipment

• Damage to the equipment during transportation /unloading

• Debris/Obstruction may be intervened on the path by external events

• Potential for Debris/Obstruction due

to an EE • Installation/Connection of the

portable equipment (i.e., cables and buses)

• Inadequate/loose connection • connection to wrong object (bus) • Performance degraded by the bad

working condition

• Impact on working condition (e.g.,

debris or flooding by the earthquake)

• Report to the MCR on the completion of installation /connection, and

• Startup of the generator and Closing the breaker

• (Check by the MCR and Follow-up Actions)

• Omission of report on completion of connection work

• Omission of the generator startup • Selection of wrong circuit breaker • Failure of coordination with MCR due to

the loss of communication system

• Impact on the Communication

System

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§ Availability/Reliability of the Communication System (e.g., Breakdown of the Antennas)

§ Integrity of the storage facility, travel paths, and local places

§ Intensity of the earthquake, and the frequency and duration of the aftershock

§ Potential for Intervention of Debris/Obstructions on the travel paths (e.g., trees or lamp poles along the path, a transmission tower, transmission power lines, structural or slope collapse, etc.)

§ Effect of external events on the activities at local places (e.g., effect of typhoon on personnel’s travelling, deploying, manipulating, etc.)

§ Integrity/Availability of the offsite emergency personnel (i.e., potential for loss/impairment due to external hazards) and the travel paths into the plants

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§ Examples of Seismic Capability/Fragility for Defining DSB (just example)▪ Seismic capability of the storage facility: < 0.3g▪ Availability of the offsite emergency personnel:

< 0.3g▪ Intervention of Debris/Obstructions on the travel

paths • trees or lamp poles along the path: > 0.14g

• transmission tower, transmission power lines: >0.2g

• structural or slope collapse: > 0.26g

§ Then, DSBs for portable equipment can be classified into new categories for HRA:

• DSB1: DSB1-1 [ 0.09 - 0.14g ]; DSB1-2 [ 0.14 – 0.18g ]

• DSB2: DSB2-1 [ 0.18 – 0.2g]; DSB2-2 [ 0.2 - 0.26g ]; DSB2-3 [ 0.26 – 0.3g ]; DSB2-4 [ 0.3 – 0.5g ]

• DSB3: [ 0.5 – 2.0g ]

• DSB4: [ > 2.0g ]

[EPRI EE HRA, 2016]

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§ By DSB, feasibility analysis should be re-conducted by considering Debris/Obstructions that might be intervened on the travel paths▪ Kinds of debris/obstructions and existence of other alternative paths?

▪ Feasibility Analysis: Procedure, Command and Control, Staffing Analysis (i.e., required staff for simple obstructions and for heavy/complex obstructions), Timing Analysis (i.e., required time for removing debris/obstructions with any possible time delay), etc.

§ If the task is judged to be feasible, then give credit and assess the HEP on the task associated with deploying portable equipment.▪ DSB1: within the Design Basis Seismic Event -> Use the HEP from the K-HRA/P as it is

▪ DSB2: beyond the Design Basis Seismic Event -> Multiply the HEP from the K-HRA/P by X (i.e., X=3, 5, or 10; Specific multipliers are not determined yet for higher damage states, i.e. [0.3 –0.5g])

▪ DSB3&4: [ 0.5 – 2.0g ] No credit for portable equipment

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§ More Case Studies for Various Tasks/Activities and Context▪ Portable pumps for SG injection and flow (level) control

▪ Portable pumps for RCS injection and flow (level) control

▪ Use of multiple portable equipment for alternate residual heat removal or shutdown cooling system

▪ Under External Events or Various Weather Conditions

§ Update or Revision of HRA guideline for portable equipment▪ Reflection of state-of-the art on HEP values, PSF evaluation and weighting factors

§ Expert Elicitation for HEPs associated with Decisions and Actions for using Portable Equipment▪ A list of Task/Activity associated with using portable equipment

▪ A list of Context to be considered (PSFs, External Events, and Weather conditions)

▪ International cooperation might be pursued.

Status on the SAMG HRA for Level 2 PSA

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Very few method deals with Decision and Actions associated with use of portable equipment in SAMGs, which may require highly complicated interactions

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The modeling of SAMG actions for Level 2 PSA needs to take into account the following characteristics specific to Severe Accident Management.§ Transfer of some responsibilities from the main control room (MCR) crew to the Technical

Support Center (TSC) § Timing of the entry into SAMG, after the entry conditions are satisfied, and possible delay of

Emergency Response Organization (ERO) such as TSC/OSC/EOF to effective readiness§ Transition from preventive & prescriptive nature of emergency response (e.g., EOPs) to

mitigative & less-prescriptive nature of SAMGs§ Choice of a SAM strategy/measure depends not only on hardware system availability but

also on the Decision of the ERO (e.g., TSC) to pursue the SAM measure in a given accident condition.

§ Complex decision-making situation may arise, and distributed decision process and coordination of multiple teams (e.g. MCR crew, local operators, fire brigade, etc.) are required.

§ Phenomenological uncertainty about plant state

[References]V. Dang, G. Schoen, B. Reer, Overview of the Modelling of Severe Accident Management in the Swiss Probabilistic Safety Analyses,

ISAMM 2009 Workshop Proceedings, Vol. I, Schloss Böttstein, Switzerland, 26-28 October 2009.V. Fauchille, H. Bonneville, J.Y. Maguer, Experience Feedback from Fukushima towards Human Reliability Analysis for Level 2, PSAM 12,

Honolulu, Hawaii, June 2014.Nathan Siu, Don Marksberry, Susan Cooper, Kevin Coyne, Martin Stutzke, PSA Technology Challenges Revealed by the Great East

Japan Earthquake, PSAM Topical Conference in Light of the Fukushima Dai-Ichi Accident, Tokyo, Japan, April 15-17, 2013.

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§ The decision-making model of the TSC while following SAMG and estimation of their decision probability

§ The entry time into SAMG and the level of composition of the emergency response staff as the event progresses

§ The time required to conduct each of SAGs of the TSC SAMG

§ The availability of staff and the time required to deploy and install portable equipment (especially under external events)

§ Guideline for decomposing or analyzing the tasks or activities using portable equipment

§ The staffing assessment method for long-duration accident scenarios

§ The potential for errors of commission during extreme events and severe accidents progression

§ Modelling of coordination and collaboration activities between multiple emergency teams/organizations

§ Consideration of psychological and physiological stress due to long-term accident management activities and external hazards

Kim J., Cho J., Technical challenges in modeling human and organizational actions under severe accident conditions for Level 2 PSA, https://doi.org/10.1016/j.ress.2018.08.003, 2018.

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HORAAM SPAR-H EPRI HRA Team Decision Making (TDM) related Influencing Factors

KAERI SAMG DM-related PSF/IFs

Time for decision

Information and

measurement

means

Decision difficulty

Scenario difficulty

Difficulty for the

operator

Difficulty induced by

environmental

conditions

Degree of

involvement of the

crisis organization

Available Time

Procedure

Ergonomics and Human

Machine Interaction

Stress and Stressor

Complexity

Fitness for Duty

Work Processes

Experience and Training

Timing

Procedures and

Training

Cues and Indications

Human machine

interface

Workload, pressure,

and stress

Complexity

Special equipment

Special fitness needs

Environment

Crew communications,

staffing, and

dynamics

Time constraints

Procedures

Information factors

Monitoring

Attention

Cognition

Conflict

Context

Adaptability

Leadership

Culture

Communication

Coordination

Cooperation

Support behavior

Composition

Knowledge

Training

Time (Required vs. Available): Timeline analysis required

Quality of Guidelines: Task Analysis of SAGs

Information and HSI: correlated with the level of interaction between EROs

Coordination, Cooperation, and Communication

Cognitive Workload/Stress

Decision Complexity (Evaluation of Positive vs. Negative Impact)

Staffing (Required vs. Available): Staffing analysis required

Training

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§ TSAMG-CET@650 = Time at which SAMG entry condition (e.g., CET = 650oC and rising for a reference plant) is reached. This time information can be obtained from the accident analysis code.

§ TEA (Time for emergency alert) = Time at which emergency alert is requested or issued for calling the emergency response organization (ERO) into the site, based on the emergency plant (EP) of the site. The ERO includes emergency staff for the TSC, the OSC, the EOF, and the local emergency staff (LES) responsible for deploying and installing portable equipment.

§ TERO-Ready = Time at which each of the ERO is being functional or ready to give guidance or implement requested actions, after the emergency alert is made. It includes the time taken to travel and be ready to initiate required missions after an emergency call.

§ TTransport-and-Installation = The time required to deploy and install portable equipment

§ TDFC (Time for Diagnostic Flow Chart) = The time required for TSC to perform the diagnostic flow chart (DFC)

§ TSAG-# (Time for SAG-#) = Time required for conducting each SAG. It includes the time for system identification, decision-making of the strategy, and direction to the implementers (e.g., MCR crew or Local personnel), and monitoring the effectiveness of the strategy. It may differ from each SAG.

For DBEs or low-damage external events, TERO-Ready < TSAMG-CET@650

• If TSAMG-CET@650 or TDFC+SAG < TERO-Ready + TTransport-and-Installation, then Decision on SAG-1 and SAG-3 using portable equipment will be delayed until installation is completed; In this case, SAG-2, RCS dep’zation using SDS, would be implemented first.

Or, • If TSAMG-CET@650 or TDFC+SAG > TERO-Ready + TTransport-and-Installation, then Decision on SAG-1 and SAG-3 using portable

equipment can be made at a right time on the guidance.

Event RT Emergency Alert

TEATRT TERO-Ready

ERO (TSC/OSC/MACST staff) is ready to guide and implement

TTransport-and-Installation (Ready-for-Implementation)

TSAMG-CET@650 Time limitTDFC+SAG

TERO-Ready + TTransport-and-Installation

SAG-1, SAG-2, SAG-3, ……

SAG-1, SAG-2, SAG-3, ……

For extreme or high-damage external events, ‘TERO-Ready > TSAMG-CET@650‘ or ‘TERO-Ready + TTransport-and-Installation >> TSAMG-CET@650 or TDFC+SAG’ are expected.

Event RT Emergency Alert

TEATRT TERO-Ready

ERO (TSC/OSC/ MACST staff) is ready to guide and implement

TTransport-and-Installation (Ready-for-Implementation)

TSAMG-CET@650 Time limitTDFC+SAG

TERO-Ready (or TDFC+SAG) + TTransport-and-Installation

SAG-1, SAG-2, SAG-3, ……Entry to MCR SAMG (i.e., SACRG) SAG-1, SAG-2, SAG-3, ……

• If TSAMG-CET@650 or TDFC+SAG < TERO-Ready + TTransport-and-Installation, then Decision on SAG-1 and SAG-3 for using portable equipment will be delayed until installation is completed; In this case, SAG-2, RCS dep’zation using SDS, would be implemented first.

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§ Step 1 (Likelihood of Negative Impacts): Likelihood of an actual occurrence of individual negative impacts in a given scenario Ø 1 – High, 2 – Medium, 3 – Low

§ Step 2 (Evaluation Complexity of Negative Impacts): Level of difficulty for TSC personnel to evaluate or perceive the actual likelihood of negative impacts based on given information and computational aidsØ 1 – High, 2 – Medium, 3 – Low

§ Step 3 (Evaluation of Mitigative Actions): (1) Feasibility or Implementation Complexity of Mitigative Actions, (2) Decision Burden from the Consequences of Mitigative Actions

▪ Step 3-1 (Feasibility or Implementation Complexity of Mitigative Actions): Level of feasibility or difficulty to implement mitigative actions suggested to eliminate or lessen negative impacts, in a given scenario or context. For example, in a given situation, the equipment to be used for mitigative actions may not be available or the plant condition for the equipment to be operable may not be appropriate.Ø 1 – Very Low, 2 – Low, 3 – Medium, 4 – High, 5 – Very High

▪ Step 3-2 (Decision Burden from the Consequences of Mitigative Actions): Some mitigative actions may include other aspects of negative consequences on the plant, which may impose a burden to decide to implement mitigative actions Ø 1 – Very Low, 2 – Low, 3 – Medium, 4 – High, 5 – Very High

§ Step 4 (Influence on a Final Decision): Level of influence of the perception on negative impacts with mitigative actions on the final decision on whether to implement the strategy or not. The negative impact with mitigative actions can be manageable easily in some scenarios, whereas in other scenarios it cannot be easily dealt with by the mitigative actions since they may have limitations in implementing or negative consequences in itself. Ø 1 – Very High, 2 – High, 3 – Medium, 4 – Low, 5 – Very Low

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▪ F&B operation (Bleed RCS by opening the SDS valves) is initiated according to the EOP, but the HPSI PPs fail at an early stage due to the loss of room cooling induced by TLOCCW, and for the same reason the CS PPs also fail. SIT is only available to inject borated water into the reactor.

▪ The portable pumps for injecting the SGs, RCS, and CTMT are expected to be used as SAM measures. The portable pump for spraying into the CTMT is assumed to be available at around 24 hrs into the event.

▪ The PAR for hydrogen control is assumed to operate adequately in controlling hydrogen concentration.

TLOCCW PDS-ET

GCISTOP2

GCISTOP2GHSIGTOP

RCPSEAL_2S

GCISTOP2

GCISTOP2GHSIGTOP

GCISTOP2GSDOE

GSHR5

GCISTOP2

GCISTOP2GHSIGTOP

GCISTOP2GSDOE

GRPFAIL-T2

IE-TLOCCW

Total Loss of Component Cooling

Water SystemReactor Trip Deliver Auxiliary

Feedwater Using TDPs RCP SEAL Bleed RCS HPSIS Injection Containment Isolation

GIE-TLOCCW RT SHR RCPSEAL BD HPI CIS

Seq# State

1 OK

2 32

3 2

4 32

5 2

6 51

7 2

8 51

9 2

10 34

11 2

12 51

13 2

14 51

15 2

16 34

17 2

Pressurizer Manway in an Open State or ...?

Monitoring of Plant Safety Parameters

All SG Levels> SG_L(%) (WR) SAG-01: Inject into SG

RCS Pressure< RCS_P (kg/cm2) SAG-02: Depressurize RCS

CET < CET_T (or total RCS injection rate >

FLOW_R)SAG-03: Inject into RCS

Containment Level> CTMT_L(%) (WR) SAG-04: Inject into Containment

Site release <whole body: R1 mSv/hror thyroid: R2 mSv/hr

SAG-05: Reduce Fission Product Release

Containment Pressure< CTMT_P1 (cmH2Og)

SAG-06: Control Containment Conditions

Containment H2 < CTMT_H1 (%)

SAG-07: Control Containment Hydrogen

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

No

No

No

No

No

No

No

No

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Pressurizer Manway in an Open State or ...?

Monitoring of Plant Safety Parameters

All SG Levels> SG_L(%) (WR) SAG-01: Inject into SG

RCS Pressure< RCS_P (kg/cm2) SAG-02: Depressurize RCS

CET < CET_T (or total RCS injection rate >

FLOW_R)SAG-03: Inject into RCS

Containment Level> CTMT_L(%) (WR) SAG-04: Inject into Containment

Site release <whole body: R1 mSv/hror thyroid: R2 mSv/hr

SAG-05: Reduce Fission Product Release

Containment Pressure< CTMT_P1 (cmH2Og)

SAG-06: Control Containment Conditions

Containment H2 < CTMT_H1 (%)

SAG-07: Control Containment Hydrogen

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

No

No

No

No

No

No

No

No

*Underlying Assumption: I&Cs are not affected by the TLOCCW Event TLOCCW PDS-ET

GCISTOP2

GCISTOP2GHSIGTOP

RCPSEAL_2S

GCISTOP2

GCISTOP2GHSIGTOP

GCISTOP2GSDOE

GSHR5

GCISTOP2

GCISTOP2GHSIGTOP

GCISTOP2GSDOE

GRPFAIL-T2

IE-TLOCCW

Total Loss of Component Cooling

Water SystemReactor Trip Deliver Auxiliary

Feedwater Using TDPs RCP SEAL Bleed RCS HPSIS Injection Containment Isolation

GIE-TLOCCW RT SHR RCPSEAL BD HPI CIS

Seq# State

1 OK

2 32

3 2

4 32

5 2

6 51

7 2

8 51

9 2

10 34

11 2

12 51

13 2

14 51

15 2

16 34

17 2

CAMS/CAMA

• Injection into SGs using the Portable Pump

• No Means for injecting into CTMT

• Depressurize RCS by Opening the SDS VVs (if it is in a closed state) (*RCGVS could be opened in addition to SDS)

• CTMT Spray using the High-capacity Portable Pump

• N/A : No FP Release (assumption)

• Hydrogen is assumed to be under Normal Control

• Injection into RCS using the Portable Pump

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Related SAG

Negative Impacts (N.I.)

Mitigative Actions against N.I. Step 1: Likelihood of N.I.

Step 2: Evaluation Complexity of N.I.

Step 3-1: ImplementComplexityof M.A.

Step 3-2:Consequences of M.A.

Step 4: Influence on a Final Decision

SAG-01:Inject into SGs

Fission product release from leaking SG tubes

……

3 3 - - -

Thermal shock of SG

Limit flow to SG to xxx gpm for the first xx minutes of injection

1 3

3

4 5

Begin feeding only one SG at a time to minimize consequences of SG tube failure until minimumwide range SG level is indicated

5

Feed only isolatable SGs to minimize consequences of SG tube failure 5

Creep rupture of SG tubes

Depressurize only one hot, dry SG at a time to minimize consequences of SG tube failure

2 2

5

3 4Establish feed flow as soon as possible once SG pressure is below the shutoff head of the feed source. Limit flow to SG to xxx gpm for the first xx minutes of injection

3

Depressurize the RCS (use SAG-2) 3

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Related SAG

Negative Impacts (N.I.)

Mitigative Actions against N.I. Step 1: Likelihood of N.I.

Step 2: Evaluation Complexity of N.I.

Step 3-1: ImplementComplexityof M.A.

Step 3-2:Consequences of M.A.

Step 4: Influence on a Final Decision

SAG-06:Control CTMT Pressure

CTMT severe challenge from a hydrogen burn

……

3 3 - - -

Insufficient spray source

……3 3 - - -

Containment Flooding

Throttle spray flow to minimize rate of containment water level increase

1 2

4

3 3Use the spray pumps in recirculation mode (N/A under the given scenario)

1

Use the fan coolers (N/A under the given scenario) 1

CTMT severe challenge from over pressurization (from CCI)

3 2 - - -

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§ Detailed Task Analysis for each SAG is being conducted with the SAMG Developers▪ Required Cognition or Cognitive Functions, Availability and Location of Information, Interaction

between EROs (TSC, MCR, OSC, LES, and EOF; or Government or External Decision-Maker), Level of Perception of Negative Impacts (N.I.’s) and Evaluation of Mitigative Actions (M.A.’s) against N.I.’s, and Level of Influence of TSC’s perception on N.I.’s with M.A.’s on a Final Decision

§ Survey on SAMG Implementation Strategy or Practices

§ Time required for conducting each step of a SAG and completing a SAG

§ Time required for ERO being operational and for deploying and installing portable equipment

§ Accident analysis using MAAP for determining available time for each strategy (or SAG) against key events from CET (containment event tree)▪ Best estimate result vs. Uncertainty Analysis results

§ Quantification Method incorporating Decision making and other IFs

§ Modeling of SAM actions into Level 2 PSA