Nuclear Security Risk Analysis: An Insider-Outsider Collusion Scenario

This study analyses the vulnerability of the physical protection system (PPS) deployed at a hypothetical facility. The PPS is designed to prevent and eliminate threats to nuclear materials and facilities. The analysis considers possible outsider and insider threats. A modified adversary sequence diagram (ASD) evaluates threat pathways to test an insider-outsider collusion case. The ASD also measures the probability of adversary interruption by demonstrating the methodology for a typical nuclear facility

Summary of the meetings on the Human Reliability Program on Industries of National Importance (NIAS Report No. NIAS/NSE/U/MR/02/2021)

This meeting was jointly organised by NIAS, India and Texas A&M University, USA. HRP is widely used in the sectors requiring high standard of safety and security. As part of collaborative research between NIAS adn Texas A&M University, a discussion meeting was organized at NIAS bringing together national and international experts from diverse industries of national importance to deliberate on HRP subject matter. Further a core group was formed to further discuss on the theme and two meetings of the core group were conducted. Report of the discussions held in the three meetings is presented

The Nuclear Security Science and Policy Institute at Texas A&M University

The Nuclear Security Science and Policy Institute (NSSPI) is a multidisciplinary organization at Texas A&M University and was the first U.S. academic institution focused on technical graduate education, research, and service related to the safeguarding of nuclear materials and the reduction of nuclear threats. NSSPI employs science, engineering, and policy expertise to: (1) conduct research and development to help detect, prevent, and reverse nuclear and radiological proliferation and guard against nuclear terrorism; (2) educate the next generation of nuclear security and nuclear nonproliferation leaders; (3) analyze the interrelationships between policy and technology in the field of nuclear security; and (4) serve as a public resource for knowledge and skills to reduce nuclear threats. Since 2006, over 31 Doctoral and 73 Master degrees were awarded through NSSPI-sponsored research. Forty-one of those degrees are Master of Science in Nuclear Engineering with a specialization in Nuclear Nonproliferation and 16 were Doctorate of Philosophy degrees with a specific focus on nuclear nonproliferation. Over 200 students from both technical and policy backgrounds have taken classes provided by NSSPI at Texas A&M. The model for creating safeguards and security experts, which has in large part been replicated worldwide, was established at Texas A&M by NSSPI faculty and staff. In addition to conventional classroom lectures, NSSPI faculty have provided practical experiences; advised students on valuable research projects that have contributed substantially to the overall nuclear nonproliferation, safeguards and security arenas; and engaged several similar academic and research institutes around the world in activities and research for the benefit of Texas A&M students. NSSPI has had an enormous impact on the nuclear nonproliferation workforce (across the international community) in the past 8 years, and this paper is an attempt to summarize the activities accomplished by NSSPI during this time and the future direction of the program

Human Reliability Programs in Industries of National Importance for Safety and Security

This book discusses human reliability programs (HRPs) and their various elements, including safety and security case studies. The topics covered include significance and vulnerability aspects of human reliability and sustainable HRP, including case studies and lessons learned, methodologies used for human reliability analysis, and good practices of HRPs from various industries. Human reliability is widely used in fields requiring high standards of safety, such as the aviation, petroleum and chemical process, and nuclear industries. The book showcases contributions on the topic from experts in the field of technology, design, aviation, and nuclear industries. The book can be a valuable reference for researchers and professionals interested in HRP to ensure safety and security in industries

Evaluation of nuclear material accountability by the probability of detection for loss of Pu (LOPu) scenarios in pyroprocessing

A new methodology to analyze the nuclear material accountability for pyroprocessing system is developed. The Pu-to-244Cm ratio quantification is one of the methods for Pu accountancy in pyroprocessing. However, an uncertainty in the Pu-to-244Cm ratio due to the non-uniform composition in used fuel assemblies can affect the accountancy of Pu. A random variable, LOPu, is developed to analyze the probability of detection for Pu diversion of hypothetical scenarios at a pyroprocessing facility considering the uncertainty in Pu-to-244Cm ratio estimation. The analysis is carried out by the hypothesis testing and the event tree method. The probability of detection for diversion of 8 kg Pu is found to be less than 95% if a large size granule consisting of small size particles gets sampled for measurements. To increase the probability of detection more than 95%, first, a new Material Balance Area (MBA) structure consisting of more number of Key Measurement Points (KMPs) is designed. This multiple KMP-measurement for the MBA shows the probability of detection for 8 kg Pu diversion is greater than 96%. Increasing the granule sample number from one to ten also shows the probability of detection is greater than 95% in the most ranges for granule and powder sizes. Keywords: Safeguards, Nuclear material accountancy, Pyroprocessing, Probability of detection, Loss of Pu, Nuclear material diversion, SERPEN

Nuclide composition non-uniformity in used nuclear fuel for considerations in pyroprocessing safeguards

An analysis of a pyroprocessing safeguards methodology employing the Pu-to-244Cm ratio is presented. The analysis includes characterization of representative used nuclear fuel assemblies with respect to computed nuclide composition. The nuclide composition data computationally generated is appropriately reformatted to correspond with the material conditions after each step in the head-end stage of pyroprocessing. Uncertainty in the Pu-to-244Cm ratio is evaluated using the Geary-Hinkley transformation method. This is because the Pu-to-244Cm ratio is a Cauchy distribution since it is the ratio of two normally distributed random variables. The calculated uncertainty of the Pu-to-244Cm ratio is propagated through the mass flow stream in the pyroprocessing steps. Finally, the probability of Type-I error for the plutonium Material Unaccounted For (MUF) is evaluated by the hypothesis testing method as a function of the sizes of powder particles and granules, which are dominant parameters to determine the sample size. The results show the probability of Type-I error is occasionally greater than 5%. However, increasing granule sample sizes could surmount the weakness of material accounting because of the non-uniformity of nuclide composition. Keywords: Safeguards, MUF, Pyroprocessing, Nuclear material accountancy, Type-I error, Serpen

A Review of Human Reliability Programs for Nuclear Security

Human Reliability Program (HRP) is a set of procedures, protocols, and the corresponding performance of activities to support and sustain the secure and safe operation of a facility. Our review indicated that HRP is referred to by various names, such as, Personnel Reliability Program (PRP), Trustworthiness Program, and Fitness for Duty Program, with PRP being the most common amongst them. A brief description of the evolution of HRP and its components for Finland, Japan, Jordan, Nigeria, Russia, US, and UK is provided. Details of the Trustworthiness Program by the International Atomic Energy Agency are also provided. Most of the HRPs have similar components and implementation steps with few variations, and they all have identical objectives. Even though a structured HRP may not exist in Indian civil nuclear energy facilities, an account of various HRP components practiced in India is discussed. The HRP review provided should help security practitioners and academics

Computational and experimental forensics characterization of weapons-grade plutonium produced in a thermal neutron environment

The growing nuclear threat has amplified the need for developing diverse and accurate nuclear forensics analysis techniques to strengthen nuclear security measures. The work presented here is part of a research effort focused on developing a methodology for reactor-type discrimination of weapons-grade plutonium. To verify the developed methodology, natural UO2 fuel samples were irradiated in a thermal neutron spectrum at the University of Missouri Research Reactor (MURR) and produced approximately 20 μg of weapons-grade plutonium test material. Radiation transport simulations of common thermal reactor types that can produce weapons-grade plutonium were performed, and the results are presented here. These simulations were needed to verify whether the plutonium produced in the natural UO2 fuel samples during the experimental irradiation at MURR was a suitable representative to plutonium produced in common thermal reactor types. Also presented are comparisons of fission product and plutonium concentrations obtained from computational simulations of the experimental irradiation at MURR to the nondestructive and destructive measurements of the irradiated natural UO2 fuel samples. Gamma spectroscopy measurements of radioactive fission products were mostly within 10%, mass spectroscopy measurements of the total plutonium mass were within 4%, and mass spectroscopy measurements of stable fission products were mostly within 5%. Keywords: Neutron Irradiation, Nuclear Forensics, Weapons-grade Plutoniu

Experimental validation of a nuclear forensics methodology for source reactor-type discrimination of chemically separated plutonium

An experimental validation of a nuclear forensics methodology for the source reactor-type discrimination of separated weapons-useable plutonium is presented. The methodology uses measured values of intra-element isotope ratios of plutonium and fission product contaminants. MCNP radiation transport codes were used for various reactor core modeling and fuel burnup simulations. A reactor-dependent library of intra-element isotope ratio values as a function of burnup and time since irradiation was created from the simulation results. The experimental validation of the methodology was achieved by performing two low-burnup experimental irradiations, resulting in distinct fuel samples containing sub-milligram quantities of weapons-useable plutonium. The irradiated samples were subjected to gamma and mass spectrometry to measure several intra-element isotope ratios. For each reactor in the library, a maximum likelihood calculation was utilized to compare the measured and simulated intra-element isotope ratio values, producing a likelihood value which is proportional to the probability of observing the measured ratio values, given a particular reactor in the library. The measured intra-element isotope ratio values of both irradiated samples and its comparison with the simulation predictions using maximum likelihood analyses are presented. The analyses validate the nuclear forensics methodology developed. Keywords: Nuclear forensics, Reactor-type discrimination, Weapons-useable plutonium, Intra-element isotope ratios, Maximum likelihoo