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{{#Wiki_filter:DG-1327 ClarificationReactivity Initiated Accident GuidanceT. W. EichenbergEPRI Fuel Reliability Program, Reg
{{#Wiki_filter:DG-1327 Clarification Reactivity Initiated Accident Guidance T. W. Eichenberg EPRI Fuel Reliability Program, Reg-TAC Chair Sr. Specialist Reactor Safety Analysis, TVA January 25, 2017
-TAC ChairSr. Specialist Reactor Safety Analysis, TVAJanuary 25, 2017 *White Flint, Rockville MD 1
* White Flint, Rockville MD 1
Overview*Categories for Discussion
 
-Methods & Assumptions
Overview
-Failure Thresholds
* Categories for Discussion
-Release Fractions
  - Methods & Assumptions
-Miscellaneous 2
  - Failure Thresholds
PWR vsBWRPerspectiv e*While Rod Eject / Blade Drop are Reactivity Initiated Accidents-
  - Release Fractions
-These different events don't share an identical topology
  - Miscellaneous 2
*Analytical space is different
 
-Every assumption isn't automatically meaningful to both PWR's and BWR's-Example from item 2.2.5
PWR vs BWR Perspective
*(a) is PWR speak
* While Rod Eject / Blade Drop are Reactivity Initiated Accidents
*(b) is BWR speak-Example item 2.2.10
  - These different events dont share an identical topology
*Muddy regarding BWR 3
* Analytical space is different
  - Every assumption isnt automatically meaningful to both PWRs and BWRs
  - Example from item 2.2.5
      * (a) is PWR speak
      * (b) is BWR speak
  - Example item 2.2.10
* Muddy regarding BWR 3
 
Methods & Assumptions
Methods & Assumptions
*Approved Models
* Approved Models
-What does "account for calculational uncertainties mean"?
  - What does account for calculational uncertainties mean?
-Realistic / Risk Informed methods to be allowed?-Expecting a full RG 1.203 process?
  - Realistic / Risk Informed methods to be allowed?
4 Methods & Assumptions
  - Expecting a full RG 1.203 process?
*5% power DNB/CPR threshold?
4
-Value is below TS monitoring power level.
 
*Correlation range of applicability may not extend that low
-DNB/CPR may not be appropriate metric relative to very fast transient condition 5
Methods & Assumptions
Methods & Assumptions
*Misc. Assumptions
* 5% power DNB/CPR threshold?
-Are "sensitivity" studies going to be plant and cycle specific?
  - Value is below TS monitoring power level.
-What is NOT a "major reactivity feedback?"
* Correlation range of applicability may not extend that low
*Direct Moderator HeatingNon-Eq. T-H-What is meant by "manufacturing tolerances?"
  - DNB/CPR may not be appropriate metric relative to very fast transient condition 5
*Plant , fuel type, and/or cycle specific.As-built vs bounding tolerance
 
-Accounting for something vs. sensitivity/parametric evaluation.
Methods & Assumptions
6 Methods & Assumptions
* Misc. Assumptions
*Misc. Assumptions
  - Are sensitivity studies going to be plant and cycle specific?
-What is meant by "wider operating conditions"?
  - What is NOT a major reactivity feedback?
-Effectively, you're saying the determination of limiting conditions is non
* Direct Moderator Heating Non-Eq. T-H
-linear.*When does the search stop? To "survey a larger population" implies a realistic assessment.
  - What is meant by manufacturing tolerances?
-What is "sufficient parametric study"?
* Plant , fuel type, and/or cycle specific.
7 Methods & Assumptions
As-built vs bounding tolerance
*Misc. Assumptions
  - Accounting for something vs.
-Why do advanced methods need to implement artificial conservatism to compare against failure criteria?
sensitivity/parametric evaluation.
-Extensive focus on bounding assumptions
6
*Seems incompatible with implications of 2.2.4 (limiting scenario tied to non
 
-linear effects, not artificial conservatisms) 8 Methods & Assumptions
Methods & Assumptions
*Misc. Assumptions
* Misc. Assumptions
-Approved hydrogen pickup model is explicit
  - What is meant by wider operating conditions?
-Need for an approved hydride orientation model is not as obvious. Need to validate the failure curve utilized.-Is the use of RG 1.224 account for hydride orientation issue?
  - Effectively, youre saying the determination of limiting conditions is non-linear.
9 Failure Thresholds
* When does the search stop? To survey a larger population implies a realistic assessment.
*EPRI Test Program
  - What is sufficient parametric study?
-Why Revision 1
7
*MBT Data / NSRR corrections
 
-Temperature Effects
Methods & Assumptions
-Pulse Effects
* Misc. Assumptions
-Power History Effects
  - Why do advanced methods need to implement artificial conservatism to compare against failure criteria?
-Hydrogen > 300ppm
  - Extensive focus on bounding assumptions
-Elongation
* Seems incompatible with implications of 2.2.4 (limiting scenario tied to non-linear effects, not artificial conservatisms) 8
-FailureLimit s 10http://www.epri.com/abstracts/Pages/ProductAbstract.aspx?ProductId=000000003002005540 Failure Thresholds
 
*Best Estimate?
Methods & Assumptions
-Yes, in the sense that curve fits are relative to nominal data.
* Misc. Assumptions
-No, in the sense that the shape of curve fits displays negative impact in areas without failures*Low Hydrogen region
  - Approved hydrogen pickup model is explicit
-No, in the sense that correlation coefficients are in some casessubstantiallylessthan 1 11 Release Fractions
  - Need for an approved hydride orientation model is not as obvious. Need to validate the failure curve utilized.
*Appropriate Location
  - Is the use of RG 1.224 account for hydride orientation issue?
-Keep information in one place; remove from DG
9
-1327-Locate to 1.183, 1.195, etc. (sign of a bigger problem)*Example: Changing dose method constitutes an AST/TID backfit?
 
12 Release Fractions
Failure Thresholds
*Transient Fission Gas Release-Database doesn't represent low burnup 13 Miscellaneous
* EPRI Test Program
*Logistical Issue
  - Why Revision 1
-Approved Analytical Methods must Exist
* MBT Data / NSRR corrections
*Method reviews in a timely manner?
  - Temperature Effects
*Potential New Method Elements
  - Pulse Effects
-Transient Fission Gas Release / Mechanical aspect
  - Power History Effects
-Corrosion/Hydrogen Uptake/Crud
  - Hydrogen > 300ppm
-Hydride Characterization
  - Elongation
-FCI Impact if Centerline Melt Allowed
  - Failure Limits http://www.epri.com/abstracts/Pages/ProductAbstract.aspx?ProductId=000000003002005540 10
-Contribution of Fission Gas Release to Pressure Surge 14 Questions?? / Discussion 15}}
 
Failure Thresholds
* Best Estimate?
  - Yes, in the sense that curve fits are relative to nominal data.
  - No, in the sense that the shape of curve fits displays negative impact in areas without failures
* Low Hydrogen region
  - No, in the sense that correlation coefficients are in some cases substantially less than 1 11
 
Release Fractions
* Appropriate Location
  - Keep information in one place; remove from DG-1327
  - Locate to 1.183, 1.195, etc. (sign of a bigger problem)
* Example: Changing dose method constitutes an AST/TID backfit?
12
 
Release Fractions
* Transient Fission Gas Release
  - Database doesnt represent low burnup 13
 
Miscellaneous
* Logistical Issue
  - Approved Analytical Methods must Exist
* Method reviews in a timely manner?
* Potential New Method Elements
  - Transient Fission Gas Release / Mechanical aspect
  - Corrosion/Hydrogen Uptake/Crud
  - Hydride Characterization
  - FCI Impact if Centerline Melt Allowed
  - Contribution of Fission Gas Release to Pressure Surge 14
 
Questions?? / Discussion 15}}

Latest revision as of 09:58, 30 October 2019

NEI-EPRI Slides. DG-1327 NRC Meeting
ML17032A343
Person / Time
Site: Nuclear Energy Institute
Issue date: 02/02/2017
From: Eichenberg T
Nuclear Energy Institute
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Download: ML17032A343 (15)
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Text

DG-1327 Clarification Reactivity Initiated Accident Guidance T. W. Eichenberg EPRI Fuel Reliability Program, Reg-TAC Chair Sr. Specialist Reactor Safety Analysis, TVA January 25, 2017

  • White Flint, Rockville MD 1

Overview

  • Categories for Discussion

- Methods & Assumptions

- Failure Thresholds

- Release Fractions

- Miscellaneous 2

PWR vs BWR Perspective

  • While Rod Eject / Blade Drop are Reactivity Initiated Accidents

- These different events dont share an identical topology

  • Analytical space is different

- Every assumption isnt automatically meaningful to both PWRs and BWRs

- Example from item 2.2.5

  • (a) is PWR speak
  • (b) is BWR speak

- Example item 2.2.10

  • Muddy regarding BWR 3

Methods & Assumptions

  • Approved Models

- What does account for calculational uncertainties mean?

- Realistic / Risk Informed methods to be allowed?

- Expecting a full RG 1.203 process?

4

Methods & Assumptions

  • 5% power DNB/CPR threshold?

- Value is below TS monitoring power level.

  • Correlation range of applicability may not extend that low

- DNB/CPR may not be appropriate metric relative to very fast transient condition 5

Methods & Assumptions

  • Misc. Assumptions

- Are sensitivity studies going to be plant and cycle specific?

- What is NOT a major reactivity feedback?

  • Direct Moderator Heating Non-Eq. T-H

- What is meant by manufacturing tolerances?

  • Plant , fuel type, and/or cycle specific.

As-built vs bounding tolerance

- Accounting for something vs.

sensitivity/parametric evaluation.

6

Methods & Assumptions

  • Misc. Assumptions

- What is meant by wider operating conditions?

- Effectively, youre saying the determination of limiting conditions is non-linear.

  • When does the search stop? To survey a larger population implies a realistic assessment.

- What is sufficient parametric study?

7

Methods & Assumptions

  • Misc. Assumptions

- Why do advanced methods need to implement artificial conservatism to compare against failure criteria?

- Extensive focus on bounding assumptions

  • Seems incompatible with implications of 2.2.4 (limiting scenario tied to non-linear effects, not artificial conservatisms) 8

Methods & Assumptions

  • Misc. Assumptions

- Approved hydrogen pickup model is explicit

- Need for an approved hydride orientation model is not as obvious. Need to validate the failure curve utilized.

- Is the use of RG 1.224 account for hydride orientation issue?

9

Failure Thresholds

- Why Revision 1

  • MBT Data / NSRR corrections

- Temperature Effects

- Pulse Effects

- Power History Effects

- Hydrogen > 300ppm

- Elongation

- Failure Limits http://www.epri.com/abstracts/Pages/ProductAbstract.aspx?ProductId=000000003002005540 10

Failure Thresholds

  • Best Estimate?

- Yes, in the sense that curve fits are relative to nominal data.

- No, in the sense that the shape of curve fits displays negative impact in areas without failures

- No, in the sense that correlation coefficients are in some cases substantially less than 1 11

Release Fractions

  • Appropriate Location

- Keep information in one place; remove from DG-1327

- Locate to 1.183, 1.195, etc. (sign of a bigger problem)

  • Example: Changing dose method constitutes an AST/TID backfit?

12

Release Fractions

- Database doesnt represent low burnup 13

Miscellaneous

  • Logistical Issue

- Approved Analytical Methods must Exist

  • Method reviews in a timely manner?
  • Potential New Method Elements

- Transient Fission Gas Release / Mechanical aspect

- Corrosion/Hydrogen Uptake/Crud

- Hydride Characterization

- FCI Impact if Centerline Melt Allowed

- Contribution of Fission Gas Release to Pressure Surge 14

Questions?? / Discussion 15

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