Regulatory cross-cutting topics for fuel cycle facilities.

This report overviews crosscutting regulatory topics for nuclear fuel cycle facilities for use in the Fuel Cycle Research&Development Nuclear Fuel Cycle Evaluation and Screening study. In particular, the regulatory infrastructure and analysis capability is assessed for the following topical areas:Fire Regulations (i.e., how applicable are current Nuclear Regulatory Commission (NRC) and/or International Atomic Energy Agency (IAEA) fire regulations to advance fuel cycle facilities)Consequence Assessment (i.e., how applicable are current radionuclide transportation tools to support risk-informed regulations and Level 2 and/or 3 PRA) While not addressed in detail, the following regulatory topic is also discussed:Integrated Security, Safeguard and Safety Requirement (i.e., how applicable are current Nuclear Regulatory Commission (NRC) regulations to future fuel cycle facilities which will likely be required to balance the sometimes conflicting Material Accountability, Security, and Safety requirements.

CeLAND: search for a 4th light neutrino state with a 3 PBq 144Ce-144Pr electron antineutrino generator in KamLAND

The reactor neutrino and gallium anomalies can be tested with a 3-4 PBq (75-100 kCi scale) 144Ce-144Pr antineutrino beta-source deployed at the center or next to a large low-background liquid scintillator detector. The antineutrino generator will be produced by the Russian reprocessing plant PA Mayak as early as 2014, transported to Japan, and deployed in the Kamioka Liquid Scintillator Anti-Neutrino Detector (KamLAND) as early as 2015. KamLAND's 13 m diameter target volume provides a suitable environment to measure the energy and position dependence of the detected neutrino flux. A characteristic oscillation pattern would be visible for a baseline of about 10 m or less, providing a very clean signal of neutrino disappearance into a yet-unknown, sterile neutrino state. This will provide a comprehensive test of the electron dissaperance neutrino anomalies and could lead to the discovery of a 4th neutrino state for Delta_m^2 > 0.1 eV^2 and sin^2(2theta) > 0.05.Comment: 67 pages, 50 figures. Th. Lasserre thanks the European Research Council for support under the Starting Grant StG-30718

The environmental impacts of reprocessing used nuclear fuels: A UK case study

Historically the UK implemented a “nominal” twice-through cycle whereby used nuclear fuels were reprocessed, but uranium and plutonium were not recycled: they were stored pending a future decision by the UK Government. However, the policy for managing higher activity wastes is clear: it envisages their disposal in a Geological Disposal Facility. Consultations for siting a repository - which were suspended in 2013 - have recently restarted, but the repository will not be available for several decades at the earliest. This article presents a comprehensive LCA study on the historical UK approach for managing used nuclear fuels and the UK Government policy for disposal of higher activity wastes. The underpinning purpose is to inform policy and decision-makers concerned with decisions on the future of the UK nuclear fuel cycle. The study relies on a combination of operational data from the Sellafield site – the industrial complex home to the UK reprocessing plants - and literature data on the GDF, and on a number of assumptions regarding the GDF design and disposal of higher activity wastes. The results reveal that a great proportion of the environmental impacts can be linked to two specific causes: indirect burdens from production of uranyl nitrate, which is used to separate plutonium from uranium, and copper, proposed in one scenario to be used as the outer layer of the disposal canister for High Level Waste. The results also demonstrate that the carbon intensity of the management of used nuclear fuels is practically negligible when compared with results from other LCA studies that cover the entire fuel cycle

IDENTIFICATION OF ELECTROREFINER AND CATHODE PROCESSING FAILURE MODES AND DETERMINATION OF SIGNATURE-SIGNIFICANCE FOR INTEGRATION INTO A SIGNATURE BASED SAFEGUARDS FRAMEWORK FOR PYROPROCESSING

The traditional method of safeguarding nuclear facilities, nuclear material accountancy (NMA), faces many challenges when applied to pyroprocessing facilities. To aid in the safeguarding of these facilities, process monitoring (PM) is being investigated as a complementary method to NMA. PM takes general process data, such as density, current etc., and applies it to safeguards through the use of a statistical framework. Signature Based Safeguards (SBS), a proposed statistical framework for the application of PM techniques, identifies anomalous scenarios and subsequently identifies and detects their respective PM signatures from a system of sensors. This work focuses both on assisting SBS through identifying anomalous scenarios, and on the computer modeling of these failure modes and the PM signatures for them. The anomalous scenarios investigated were mechanical failure modes with potential safeguards-significance as they could lead to the deposition of plutonium and other actinides in the final uranium product ingot. The signatures of these anomalous scenarios were primarily radiation signatures from a coincidence counter that is used to analyze the final ingots. Several different failure modes were identified for both the electrorefiner and the cathode processor. The signatures for these failure modes were then determined by coupling two separate computer models. The first model is a FORTRAN-based electrorefiner code named ERAD capable of modeling the mass transport of metals within an electrorefiner. The second model was an MCNP-based simulation of the Canberra JCC-31 High Level Neutron Coincidence Counter. First, the identified failure modes were simulated by changing ERAD inputs. ERAD calculated an elemental mass composition at the cathode which was then used as the final ingot composition. The final ingot composition was analyzed for single and double neutron coincidence count rates using the MCNP model. The results demonstrate significant radiation signatures for the presence of plutonium as a result of the electrorefiner failure modes. Signatures from cathode processor failure modes were weak and thus warrant future investigation of better detectors for integration into a SBS framework

Operationalising the use of Life Cycle Assessment to nuclear waste management

After decades of declining interest, nuclear energy is poised for a comeback in the UK, driven primarily by pledges and binding agreements on limiting greenhouse gas emissions, but also by increasing energy security concerns. However, the industry has yet to tackle some of its most crucial challenges regarding management of used nuclear fuels, and especially of highly radioactive wastes. Life Cycle Assessment (LCA) – indeed the most mature and also the only standardised life-cycle methodology – represents a widely accepted tool for quantifying the environmental impacts associated with goods or services and supporting decision-making processes. This Thesis aims at operationalising the use of LCA to nuclear waste management. After introducing the LCA standard methodology, the Thesis proceeds with a comprehensive review of methodologies for assessing radiological impacts – the lack of an appropriate approach for radiological impacts in LCA is in fact identified as the crucial barrier for its application to the industry, especially with respect to waste management. Building upon the main findings of the review, the Thesis presents an overarching framework and two practical methodologies – namely UCrad and the Critical Group Methodology (CGM) – for assessing radiological impacts of direct discharges, and crucially, of nuclear waste disposed of in a geological repository. The LCA and the methodologies for radiological impacts are then applied to two case studies. The first is a prospective attributional study that examines the current procedure for managing used nuclear fuels and the UK Government policy for disposal of nuclear waste in the UK. The objective is to identify hot-spots and suggest potential improvements. The study shows that the highest impacts are due to the production of chemicals required by the reprocessing process and the materials used for High Level Waste canisters rather than the construction and decommissioning of a final repository for nuclear waste. The second study focuses on future scenarios for managing used nuclear fuels in the UK, including direct disposal and four reprocessing options, and clearly demonstrates how LCA can be used to support decisions. Reprocessing of uranium, but especially of plutonium, is shown to be of crucial importance from an environmental perspective