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IAEA International Atomic Energy Agency

Technical Support Guidelines Module 3

IAEA Training Workshop on Severe Accident Management Guideline Development using the IAEA SAMG-D Toolkit

Jeff Gabor

IAEA

Technical Support Guidance

• What are TSGs? • Evolution of TSGs • Is there a regulatory driver? • Why are TSGs needed? (additional expertise /

Fukushima) • Relationship of TSGs to Plant Procedures • What are the key elements of TSGs? • Who implements them? – Responsibilities • Calculational Tools • TSG Development • Summary

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TSG Purpose

• Specify engineering support activities • Implement by the Emergency Response

Organization (ERO) staff • Directly assist the control room operating

crew and TSC evaluators and decision makers

• Support execution of Emergency Operating Procedures (EOPs) and the Severe Accident Guidelines (SAGs).

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TSG Historical Evolution • Severe accident closure 1992 – NUMARC 92-01 • BWR products

• TSGs were implemented to varying levels of detail and rigor (1996-1998) examples of full implementation include: • DAEC • Fermi • Columbia • Fitzpatrick • NMP

BWROG Generic Products

Plant Specific Products

EPGs EOPs SAGs SAGs TSGs TSGs

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TSG Development

• There currently is no rule, regulation, or generic letter specifying the contents of accident management documents.

• Documents that are referenced: • NRC SECY 88-147 - 1988 • NRC SECY 89-012 - 1989 • NUMARC 91-04 - 1992 • NRC Response to PWR AMGs - 1994 • NRC Presentation Slides from the NEI Workshop - 1994

• Concept Tested: DAEC in 1994 hosted a full drill scenario with U.S. and foreign observers to demonstrate the feasibility of the TSG concept – result successful demonstration

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TSG Development (cont’d)

• BWROG developed EPG/SAG Rev. 3 • Broadened the decision-making requirements in SAG • Specifically, BWROG noted the value of the TSGs to

support this broader functional level decision-making • Rev. 3 of BWROG SAGs focused decision making

on functional determination not strictly “observed symptoms”. This requires greater cognizance of the accident progression, its identification, and use of calculational aids

• BWROG has developed a simplified TSG to support EPG/SAG Rev. 3

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TSG Development (cont’d)

• BWROG TSGs for use with Rev. 3 EPG/SAG are formulated to address decision-making and its inputs for both: • EOPs • SAGs

• NTTF Recommendation 8 (Onsite Emergency Response Capabilities) has been rolled into a consolidated rulemaking with SBO response

• This presentation highlights key decisions in the SAGs that could be optimized by TSG inputs

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Impetus for TSGs from Fukushima Daiichi Accident Insights

• Data input is critical to support decision-making • Trending assists in prioritization • Understanding severe accident phenomena and

timelines assist in recognizing critical events • System operability assessment

• Allows projection of time to future needs • Identifies support systems necessary

• Interpretation of SAGs in light of current and projected plant conditions -- Examples: • Functional situations (containment impaired) • Core debris may not be retained in RPV • RPV breached

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Recommendation 8 from NTTF on Fukushima: On-Site Emergency Response Capabilities (DRAFT)

• Reinforce and be consistent with site command and control structure • NEI 13-06: Enhancements to emergency response capabilities for

beyond design basis accidents and events • NEI 14-01: Development of Mitigation and Management Guidelines

for Severe Accidents and Extreme Events • NRC: On-site Emergency Response Capabilities

• EOPs • SAMGs • SAMG support procedures • EDMGs

However, there is no specific reference to TSGs in any of these documents

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* Note Rec 8 has the following: Section 4.5 also makes open-ended references to the use of simulators and enhancement of simulators including the following:

“Licensees’ plant reference simulators should be further developed to simulate a severe accident by simulating the response of accident monitoring instrumentation during severe accidents”.

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Why are TSGs Needed?

• BWROG EPG/SAG Rev. 3 has a large number of decisions that need to be made

• Many decisions have introduced a substantial degree of Engineering evaluation to optimize the decisions given the potential competing effects

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Critical Decision-Making Junctures in EPG/SAG: Examples

• EOPs • Adequate core cooling • Anticipatory containment venting • RCIC survivability • Emergency Depressurization

• Limited when turbine driven systems are all that is available (Select pressure band)

• Use of alternate systems • RPV water level above TAF • Transition to SAGs

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Critical Decision Making Junctures in EPG/SAG: Examples (cont'd)

• SAGs • RPV breach • RPV injection flow > MDRIR

• MDRIR = Minimum Debris Retention Injection Rate • Pressure suppression required • RPV water level above BAF • DW sprays can be initiated and controlled

• Initiation • Flow Rate • Termination

• DWSIL curve no longer included in SAGs • DWSIL = Drywell Spray Initiation Limit

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• Venting • Initiation • Pathway selection • Control band specification • Coordination with containment flood • Coordination with RPV breach

• Core debris can be maintained within RPV • Core debris cannot be maintained within RPV • Containment flooding

• Decision to initiate • Coordination with RPV pressure control • Coordination with containment venting

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• Containment water level control band • Containment pressure level control band • Water management

• Injection • Discharge

• RPV venting • Default actions given loss of indication

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RPV Breach Signature Flow Chart

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RelationshipEOP.pptx 10-07-2015

Relationship: Accident Management Guidelines and Plant Procedures

• Establish communications • Perform notifications • Actions to shutdown the reactor • Actions to inject into the reactor • Damage assessment • Transition to other Ops Procedures when

ERO manned

Extreme Damage Mitigation Guidelines (EDMGs)

Abnormal Operating Procedures

• Integrated Response Plan for Large Scale events

Emergency Management Guidelines (EMGs)

• SAG 1 – RPV and Primary Containment Flooding Severe Accident Guideline

• SAG 2 – Containment and Radioactivity Release Severe Accident Guideline

• SAG 3 – Hydrogen Control Guideline

Severe Accident Management Guidelines (SAMGs)

• EOP 1 – RPV Control • EOP 2 – Primary Containment Control • EOP 3 – Secondary Containment Control • EOP 4 – Radiation Release Control • ALC – Alternate Level Control • ED – Emergency RPV Depressurization • ATWS RPV Control • RPV/F – RPV Flooding

Emergency Operating Procedures (EOPs)

• 100 – Rod Insertion Procedures (RIPs) • 200 – EOP Defeats • 300 – Supplemental Emergency

Procedures (SEPs) • 400 – Alternate Injection Procedures (AIPs) • 500 – EOP Flowchart Supporting CALCs • 600 – EOP Flowchart Supporting Graphs

(GRAPHs) • 700 – Severe Acc Mgmt Procedures

(SAMPs)

EOP/SAG Support Procedures

• Control Parameter Assessment Guideline (CPAG)

• System Status Assessment Guideline (SSAG)

• Plant Status Assessment Guideline (PSAG) • EOP/SAG Action Assessment Guideline

(EAAG)

Technical Support Guidelines

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Structure of Technical Support Guidelines (TSGs)

Guideline Purpose Control Parameter Assessment Guideline (CPAG)

Identify best estimate value for each EOP and SAG control parameter

Plant Status Assessment Guideline (PSAG)

Forecast the future values of control parameters

System Status Assessment Guideline (SSAG)

Establish operability and reliability of plant systems

EOP/SAG Action Assessment Guideline (EAAG)

Priority and timing for actions directed by the EOPs/SAGs

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Products and Supporting Elements of TSGs

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CPAG: Monitor Key Control Parameters Using Available Instrumentation

ERIS

PIS Number

Readout

Range

Power Supply

Isometric

Other Limitations and Adjustments

Sensor Location

Transmitter Location

Environmental Limitations [1]

Temp. Limit (°F) Reading °F Adjusted °F

PRIMARY PT#259 T50N404A T50-R800A

PT#11 H11-P601

0-400°F (SD-2861-2B)

TORUS Temp. DIV I AZ 2700

RB/Bsmnt Grid 2700 El. 551’04”

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T50N405A T50-R800A PT#12 H11-P601

0-400°F (SD-2861-2B)

TORUS Temp. DIV I AZ 00


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T50N405B T50-R800B PT#12 H11-P602

0-400°F (SD-2861-2A)

TORUS Temp. DIV II AZ 900


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PT#111 T23N001 T23-R800 CH 1 H11-P601

0-100°F (I-2860-9)

TORUS Wtr. Temp. AZ 220

DW Grid 220 El. 551’01”

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PT#112 T23N002 T23-R800 CH 2 H11-P601

0-100°F (I-2860-9)


DW Grid 670 El. 556’01”

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PT#112 T23N003 T23-R800 CH 3 H11-P601

0-100°F (I-2860-9)


DW Grid 1120 El. 556’01”

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PT#4 T23N004 T23-R800 CH 4 H11-P601

0-100°F (I-2860-9)


DW Grid 1570 El. 556’01”

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PT#115 T23N005 T23-R800 CH 5 H11-P601

0-100°F (I-2860-9)


DW Grid 2020 El. 556’01”

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PT#116 T23N006 T23-R800 CH 6 H11-P601

0-100°F (I-2860-9)


DW Grid 2470 El. 556’01”

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PT#117 T23N007 T23-R800 CH 7 H11-P601

0-100°F (I-2860-9)


DW Grid 2920 El. 556’01”

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PT#118 T23N008 T23-R800 CH 8 H11-P601

0-100°F (I-2860-9)


DW Grid 3370 El. 556’01”

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ALTERNATE E11N004A E11-R601A

Red Pen H11-P601

0-400°F

RHR Ht. XGHR “A” Inlet Temp. DIV I

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E11N004B E11-R601B Red Pen H11-P602

0-400°F

RHR Ht. XGHR “B” Inlet Temp. DIV II

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Example: Torus Water Temperature

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CPAG Trending Example Torus Temperature Forecasting

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Example: Torus Level Forecasting (Wide Range)

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Example: Containment Water Level Forecasting

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System Status Assessment Guideline (SSAG): Toolbox of Accident Management Actions to Prolong RCIC Operation Under ELAP Conditions: Pinch Points

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RCIC Critical “Pinch Point” Accident Management Actions Maintain DC Power • Perform DC load shed

• Install portable generator

• Recover AC power (offsite/EDG)

• Cross tie TSC EDG

Maintain Adequate Lube Oil Cooling via the Working Fluid

• Prefer CST as the suction source (see Attachment YA)

• Replenish CST if necessary

• Cool torus

• Anticipatory vent to minimize the maximum torus temperature

Maintain Adequate RPV Pressure • Maintain adequate steam pressure band when depending on RCIC for adequate core cooling

Maintain High Turbine Speed • Maintain high RPMs on turbine to ensure adequate lubrication if high temperature water source is being used. (>3500 RPM at suction temperatures >200°F)

Maintain Adequate NPSH • Control torus water level

• Make up for vented non-condensables with non-combustibles

• Minimize torus temperature increase

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RCIC Critical “Pinch Point” Accident Management Actions Ensure Adequate Room Cooling and Prevent High Room Temperature Trips

• Open door on the RCIC room

• Provide portable gas powered fan

• Bypass high room temperature trips

Prevent High Steam Line Temperature Trip

• Insert temperature isolation interlock DEFEAT 18

Prevent RCIC Room Flooding • ARP 1C14A<A-4> and, <B-4> (above max safe, above max normal, respectively) direct monitoring and refer operators to EOP-3.

• EOP-3 to verify that all available sump pumps are operating to lower water level.

(There is no installed equipment that could be used to limit flooding or arrest the rate of water level rise besides the sump pump.)

Prevent High Turbine Exhaust Pressure Trip

• Provide a set point change that permanently increases the high pressure trip to ~100 psig as recommended by GEH

Implement Authorized Bypasses of RCIC Protective Isolations and Trips

• Bypass the high RPV water level trip (DEFEAT 8)(1)

• Bypass the low RPV pressure isolation (DEFEAT 1)

• Bypass the high room temperature isolation (DEFEAT 18)

Note to Table: (1) For HPCI this is Defeat 7; in addition, the high torus water level suction transfer is Defeat 2.

System Status Assessment Guideline (SSAG): Toolbox of Accident Management Actions to Prolong RCIC Operation Under ELAP Conditions: Pinch Points (cont'd)

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SSAG System Indications: Toolbox of Information Inputs to Prolong RCIC Operation During SBO

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RCIC Functional Concern Indications Functional Alternatives Notes

Loss of Control Power

• Annunciator 1C04C<B-9>

• No battery charger operating for 125 VDC Div 2

• Restore battery charger per OI 302

• Restore battery charging using TSC Generator per AOP 301.1 Attachment 10

• Restore Battery Charging using SAMP 704

• Operating RCIC manually using SAMP 703

• Emergency SRV Operation using Portable DC – SAMP 707

High Oil Temperature

• Annunciators(4) 1C04C<B-5> and 1C04C<B-7>

• Switch to CST • Lower torus temperature

(3)

High Room Temperature

• Annunciator(5) 1C04B<B-4>

• Bypass high temperature trip per EOP Defeat 18

• Open Door 219 • Establish Portable ventilation

(3)

High Exhaust Back Pressure

• Annunciator 1C04C<B-8>

• Computer Point B511

• Vent containment • Jumper out the isolation

signal (not yet defined)

(1)

Low Net Positive Suction Head

• Annunciator(6) 1C04C<D-5>

• Close containment vent • Add non-condensable • Add water to torus

(3)

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SSAG System Indications: Toolbox of Information Inputs to Prolong RCIC Operation During SBO (cont’d)


High Suppression Pool Temperature

• Use anticipatory vent to limit suppression pool temperature

• Add water to torus

(3)

Low Condensate Storage Tank Level

• Annunciators(7) 1C06C<B-8>, <B-9>, C-8>, <C-9>

• Annunciator(8) 1C03C<D-3>

• Transfer suction to Torus per OI 150

• Replenish CST inventory using SAMP 710

• Transfer hotwell inventory to CST per OI 644(9)

(3)

High Bearing Vibration

(10) (3)

Turbine Over Speed Trip

• Annunciator 1C04C<A-5>

• Need to avoid the mechanical overspeed because local reset is required.

(3)

High Water Level in RCIC Room(11)

• Annunciators 1C14A<A-4>, <B-4>

• Use portable sump pump to remove water (not yet defined)

(3)

High Torus Water Level

• Annunciator 1C03B<D-9>

• Discharge water to radwaste

• Discharge water to over flow (not yet defined)

(3)

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Low Torus Water Level

• Annunciator 1C03B<D-9>

• Add water to torus (3)

Adequate Turbine Speed

• SI-2284 (RCIC Turbine Speed)

• Increase RPMs if suction temperature increases [Y-1]

(2)

HCL • RPV pressure • Torus water

temperature

• Open ADS SRVs • Open MSL drains to

condenser

PSP • Containment pressure

• Torus water level

• DW sprays • Open ADS SRVs • Open MSL drains to

condenser

DW/T • DW temperature • DW sprays

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SSAG System Indications: Toolbox of Information Inputs to Prolong RCIC Operation During SBO (cont’d)

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Responsibilities of the Accident Management Team (AMT)

Accident Management Team (Proposed)

Responsibilities Primary Backup

Parameter Monitor and Trending (CPAG and PSAG)

• Trending Control Parameters • Estimate RPV Injection • Forecasting • Control Parameter Assessment • Instrument Assessment • System Status Assessment

Technical Analysis (SSAG and EAAG)

• Confirm Rx Shutdown • Identify RPV Breach • Identify Fuel Damage • Estimate Release Rates

• Optimize Timing of EOP/SAG Actions

Operations Liaison (EAAG) • Follow SAGs • Decision Making • Forecast Actions • Identify Transition to SAGs • Determine SAG Branch • Assess Containment Flood Implications • Identify SAG steps with Flexibility • Optimize Timing of EOP/SAG Actions

― Containment Flooding ― Torus Spray ― DW Spray ― Venting ― Boron Initiation ― Alternate Room Cooling

• Prioritize System Restoration

• H2 Control Method Assessment

• Anticipate Actions

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EAAG: Operations Liaison - Integrator

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SYSTEM STATUS

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Example Calculational Tools

• Containment water volume • Containment overview – wall chart • Vent checklist – wall chart Other examples included in generic BWROG TSG: • MPSPCWL change as function of

temperature • RPV Water level correction vs. pressure • Reactor power vs. Rx pressure for SRV or

TBV

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Calculation Tools: Primary Containment Level Determination

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RPV Volume Versus Elevation (Example)

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Parameter Display Figure

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Elevation Water Volume

Level

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Who Implements TSGs? Accident Management Team in TSC

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TSG Development

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Plant SpecificTSG

Development Calculational Tools

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Emphasis on Training

• Assistance in EOP/SAG implementation requires knowledge of: • Plant Procedures • Plant Responses • Available mitigative equipment and actions • Limitations on actions • Accident phenomena • Accident progression signatures • Accident progression timing

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Areas of Concern for TSGs

• Development costs • Maintenance of the documentation

• Guidance • Data tables • Drawings

• Staffing of TSC/AMT • Training on the TSGs • Implementation proficiency • Fidelity of testing

• Table top • Simulator • PC based/Severe accident case driven

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Insights

• TSC appears to be a desirable location to be implemented by trained Engineers/SROs

• TSGs can be used to: • Set priorities for mitigative actions under

conditions of limited resources • Identify timing of mitigative actions • Select systems/pathways/sources to be used for:

• Vent • RPV injection • Containment injection

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Insights (cont’d)

• Monitor portable equipment deployment and alignment (track progress, timing, resources compared with accident progression)

• Address issues as a result of containment impairment • Leakage locations • Loss of water • Hydrogen release and impacts • Lost access • Management of water injected • Compromised SAG specified actions:

• Inject from internal sources • Flood containment

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Summary

• TSGs support implementation of complex strategies

• TSGs have been developed by BWROG • There is no regulatory requirement for TSGs • Operating accident at Fukushima identified

potential benefit of additional guidance on degraded plant conditions

• TSGs include • Control parameter monitoring • Trending of control parameters • System readiness evaluation • Assessment of strategies and prioritization

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Questions?