november 9, 2005 thomas hill, nsnfp doe spent nuclear fuel licensing path forward pactec review of...

November 9, 2005

Thomas Hill, NSNFP

DOE Spent Nuclear Fuel Licensing Path Forward

PacTec Review of Transportation Strategy for DOE Fuel

Background

• Significant discussion on the licensing approach for transportation of DOE SNF

• Industry peer-review of existing analyses and documentation

• Understand industry practices

• PacTec subcontracted to provide review and help guide DOE efforts

Outline

• Scope of review

• PacTec review summary

• Analysis methodology

• Division of responsibilities

• Path forward

Scope of Review

• Review DOE SNF grouping strategy and evaluate adequacy for use by transportation cask vendors

• Review design, documentation and testing of DOE canisters and baskets

• Evaluate use of new gadolinium neutron absorber for structural and criticality control

• Propose a path forward

PacTec Review Summary

• “Transportation should be built around these well-defined and tested canisters”

• “Canister is the interface between DOE and cask vendors”

• “The fuel should be grouped into common types”

• “Significant analyses required”

• Step wise licensing “Amending each license”

• “Meet early with the regulator [NRC] and present overall situation and strategy”

Design, Documentation and Testing DOE Canister and Basket• Canisters are fully welded pressure vessels to ASME Boiler

and Pressure Vessel Code (full penetration closure weld)

• Canister basket design details inadequate for transportation analyses

• Testing provides strong case for NRC to accept as containment boundary – Needs to address transportation conditions

• Moderator exclusion supported by design, evaluations, testing, and fabrication program

• Canister provides the interface between DOE and cask vendors – responsibilities defined by this interface

Grouping Strategy/Evaluate Adequacy

• Reasonable approach for 250 fuel types – specific groupings may change from groupings used for repository analyses to include basket configurations

• Needs to consider shipping facilities, transportation, and storage/disposition requirements

• Need to identify bounding parameters for each grouping

• Develop step-by-step approach approved by NRC

Step wise approach to fuel grouping

• License based on

– Well defined fuel group and basket configuration

– Consistent properties

• Once NRC approves a group amend C of C to include other types of fuel

Significant Analyses Required

• Criticality is a very complex analysis

• To understand the bounding nature of the various parameters, significant analyses will have to be performed

• Grouping and bounding approach has been developed in to a concise methodology

Analysis MethodologyTransportation

Canister

CanisterIntegrity

CanisterDry

Fuel Geometry/Fuel DamageUnimportant

Keff<<0.95

Canister \Flooded

BasketStructure

FuelCondition

CriticalityAnalysis

CaskC of C

Unlikely

CaskC of C

Fuel IntactPoison

CaskC of C

Fuel DegradedPoison

BasketTemplate

Criticality Analysis

CaskC of C

ShippingAssumptions

Intact

Intact Intact

Breached Degraded

Gadolinium Neutron Absorber for Structural and Criticality Control• New material with no documented history

– Produced in mill runs

– Fabrication, welding

– As a neutron absorber

• No ASME code rules governing internal basket structure

• NRC acceptability needs to be worked ASAP

Division of Responsibilities

• Canister provides interface boundary

• DOE-EM responsible for

– Canister design

– Canister internals

– Fuel loading

– Analyses of loaded canisters

– Data packages for transportation vendors

• DOE-RW (Transportation cask vendors) responsible for

– Cask and internals design

– Analyses of multiple canister within cask

Path Forward

• Prepare plan for developing topical report on DOE canister for NRC

• Meet with NRC immediately to discuss major issues

– Methodology for satisfying transportation criticality

– Moderator exclusion for canisters

– Selective flooding

– Method of determining bounding criticality cases for groupings

– Gadolinium poison

Path Forward (continued)

• Interface with cask vendors for review of methodology

– Moderator exclusion simplifies interface

• Review plan with DOE-RW second week of December

• Review plan and methodology with NRC week of INMM meeting, January 2006