Modeling and Analysis of a Representative Fission Product Removal System for a Vented

Helium Cooled Fast Reactor

Wesley Deason, Saturday, January 26th, 2013

2013 OSU-ANS Winter Conference

Agenda

• Background• Project Purpose• Project Methods• Current Progress• Future Work

What is Vented Fuel?

• Simply the venting of accumulated fission product gases.

Why vent?• Removes cladding pressure • Decreases volatile source term • Allows greater control of fission products

Historic Vented Fuel Design

General Electric: Fast Ceramic Reactor General Atomic: Peach Bottom Unit 1

Project Purpose

• To quantify feasibility and safety.

• Feasibility– Can it be built for reasonable cost?

• Is Commercial or Government research required?• NRC approval?• Construction time?

• Safety – Is it more safe or less safe than current designs?

Current Progress

• Completed Extensive Literature Review– Previous Reactor Designs• PB Unit 1, GCFR, SFR, LMFRB, DFR, EM2, TID, GFR

– Helium Purification System Design• Filter/Absorbers, molecular sieves, and cold charcoal

beds– Fission Gas Behavior in HTGRs• Release Rates from fuel

STELLA Modeling

• Determination of significant fission products– Ignore short lived and low yield fission products

STELLA Modeling

• Development of an accurate and efficient modeling methodology– Ideal: model all significant nuclides together• Activation/Depletion due to Neutron Absorption• Interdependence due to chemical reactions• Parent/Daughter decay chain tracking throughout

system

STELLA Modeling

• Development of an accurate and efficient modeling methodology– Compromise: model significant decay chains

together• Parent daughter decay chain tracking in system• Assume activation and depletion of fission products is

minimal in fast environment• Treat chemical interactions independent from other

elements

STELLA Modeling

Future Work

• Determination of interaction parameters– Element dependent

• Filter fractions• Leakage fractions• Plate-out (adsorption) fractions

• Development of desired system studies– Tests for meeting project objectives

• Reach conclusions on system feasibility and safety