Nuclear Engineering ETDs

Publication Date

Spring 3-27-2018

Abstract

Traditional nuclear material accountancy (NMA) faces several challenges when applied to pyroprocessing facilities. To address these challenges, alternative methods of safeguarding nuclear material are being developed. One method is process monitoring (PM). PM involves taking operational process data and applying it to safeguards using an advanced framework. Signature Based Safeguards (SBS), a proposed PM framework, involves the identification of anomalous scenarios and the subsequent identification and detection of their respective PM signatures from a system of measurements. SBS has previously focused on failure modes that result in transfer of mass to unexpected places in the mass flowsheet. This work developed a methodology for the identification of failure modes and determined their effect on the facility mass balance. To develop a methodology for the identification of off-normal scenarios, a modified failure mode and effects analysis (FMEA) was developed with a safeguards focus and applied to a commercial pyroprocessing electrorefiner (ER). The modified FMEA significantly expands the understanding of ER failures. To determine the effect of the failure modes on vii the mass balance, work was first performed to determine if the computational ER model Enhanced REFIN with Anodic Dissolution (ERAD) could be used as modeling tool for SBS. This was done by performing experiments to act as analogues for a postulated failure mode. These experiments were then modeled in ERAD and the computational and analytical data compared. The results indicated that ERAD is an effective tool for qualitative analysis of pyroprocessing but not for quantitative design purposes. Simulations of several failure modes identified by the modified FMEA were undertaken to produce data to be integrated into the pyroprocessing systems model Echem SSPM. Eleven different identified failure modes were simulated for four base operational cases. The simulations effectively produced results that could be used as ER data in the SSPM Echem. Simulations in Echem utilizing this integrated ERAD data allow the impact of the failure mode on the mass balance of the facility to be assessed. The results of these simulations implied that failures modes can affect the mass balance and must be assessed for operational effects.

Keywords

Safeguards, Pyroprocessing, PM, FMEA, SBS

Document Type

Dissertation

Language

English

Degree Name

Nuclear Engineering

Level of Degree

Doctoral

Department Name

Nuclear Engineering

First Committee Member (Chair)

Cassiano Endres De Oliviera

Second Committee Member

Adam Hecht

Third Committee Member

Plamen Atanassov

Fourth Committee Member

Edward Blandford

Fifth Committee Member

Edward Arthur

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