ML20079J118
| ML20079J118 | |
| Person / Time | |
|---|---|
| Site: | Nuclear Energy Institute |
| Issue date: | 03/25/2020 |
| From: | Nuclear Energy Institute |
| To: | Office of Nuclear Material Safety and Safeguards |
| Kallan P | |
| References | |
| Download: ML20079J118 (8) | |
Text
©2020 Nuclear Energy Institute NEI/NRC Workshop Spent Fuel Performance Margins:
Source Terms March 25 and 26, 2020 Washington DC
©2020 Nuclear Energy Institute 2 Agenda Goal Steps of the RIRP Technical Discussions on Selected Parameters
©2020 Nuclear Energy Institute 3 Goal Establish a set (or sets) of acceptable input parameters, assumptions and codes for source term calculations For cask loading, this should result in source terms close to best estimate since subsequent analyses using the source terms already include conservatisms Should provide clarification on where parameter values are taken from and what, if any, adjustments need to be applied Should allow simplifying the source term analyses, unless simplifications would result in significant conservatisms There maybe more then one set, maybe for different code versions, or for different applications This is to clarify the calculation of source terms (decay heat or strength of nuclear sources), not for establishing TS limits.
©2020 Nuclear Energy Institute 4 Steps of the RIRP Prepare list of input parameters and assumptions Review each parameter/assumption with respect to the goal Review source term codes and code versions Review effect of number and location of fuel assemblies in a cask Establish sets of parameters/assumptions/codes
©2020 Nuclear Energy Institute 5 Input Parameters and Assumptions Burnup Enrichment Cooling time Fuel Mass Power Density Irradiation History (Cycle / Outage lengths)
Moderator Temperature Fuel Temperature Void Coefficient (BWR)
Axial Burnup Profile Axial Moderator Temperature Profile (PWR)
Axial Void Coefficient Profile (BWR)
©2020 Nuclear Energy Institute 6 Reviews Parameters / Assumption
Source (e.g. FSAR / Actual / Public Document)
Relevance (Sensitivity of calculated source term to the parameter)
Bias and/or Uncertainty (only if unavoidable)
Codes
Any Benchmarking / Bias / Uncertainty Number and Location of assemblies in casks
Uncertainties to be combined statistically
Relevance based on location
©2020 Nuclear Energy Institute 7 Establish Sets We expect that at least three sets would be established
FSAR (generic, representative)
Actual (detailed, close to best estimate, per assembly)
Actual (simplified, reduced number of parameters, added conservatism)
©2020 Nuclear Energy Institute 8 Selected Technical Discussions Burnup
A burnup or burnup record uncertainty does not seem necessary based on the number of assemblies per cask
Fuel Mass
Should be considered for cask loading evaluations, specifically when calculating decay heat, to avoid unnecessary conservatism
Irradiation History
Consider for cask loading evaluations
Axial Profiles
To be discussed