Neutron detection is an integral part of the global effort to prevent the proliferation of special nuclear material (SNM). Applications relying on neutron-detection technology range from traditional nuclear nonproliferation objectives, such as safeguarding material and verifying stockpile reductions, to the interdiction of SNM—a goal that has recently risen in priority to a level on par with traditional missions. Large multinational programs targeting interdiction and safeguards have deployed radiation-detection assets across the globe. In parallel with these deployments of commercially available technology, significant research and development has been directed toward the creation of next-generation assets. Neutron-detection technology plays a prominent role because of the capability of neutrons to penetrate materials that readily absorb gamma rays and the unique fission signatures neutrons possess. One particularly acute technology-development challenge results from dwindling supplies of H3e, partially ...

Securing Special Nuclear Material: Recent Advances in Neutron Detection and Their Role in Nonproliferation

Passive Nondestructive Assay of Nuclear Materials

Moisture characteristics of mixtures with warm mix asphalt technologies – A review

The far site detector complex of the Daya Bay reactor experiment is proposed as a location to search for sterile neutrinos with ≥eV mass. Antineutrinos from a 500 kCi ^(144)Ce-^(144)Pr β-decay source (ΔQ=2.996  MeV) would be detected by four identical 20-ton antineutrino targets. The site layout allows flexible source placement; several specific source locations are discussed. In one year, the 3+1 sterile neutrino hypothesis can be tested at essentially the full suggested range of the parameters Δm^2_(new) and sin⁡^22θ_(new) (90% C.L.). The backgrounds from six nuclear reactors at ≥1.6  km distance are shown to be manageable. Advantages of performing the experiment at the Daya Bay far site are described.

Search for sterile neutrinos with a radioactive source at Daya Bay

Provided is an electronic device including a semiconductor memory. The semiconductor memory may include: a substrate; and a stepped structure including first interlayer dielectric layers and conductive layers which are alternately stacked over the substrate, wherein ends of the conductive layers are exposed along the profile of the stepped structure, and the stepped structure further includes a barrier layer formed on a sidewall of the conductive layer.

Electronic device and method for fabricating the same

A novel concept to detect pin-diversion from spent fuel assembly is proposed and described. The instrument will use multiple tiny neutron and gamma detectors in a form of cluster (detector cluster) and high precision driving system to collect radiation signatures inside pressurized water reactor (PWR) assembly. In order to validate our concept, a Monte Carlo study was done using a Monte Carlo code MCNP5. MONTEBURNS, a computational tool that links MCNP and ORIGEN, was used to produce accurate PWR spent fuel isotopic compositions. Monte Carlo simulations, using realistic fuel geometry and actual fuel material information, were performed to study radiation field inside a PWR spent fuel assembly. The preliminary Monte Carlo simulation study shows that indeed 2 dimensional neutron data, when obtained in the presence of missing pins, have data profiles distinctly different from the profiles obtained without missing pins.

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Monte carlo characterization of pressurized water reactor spent fuel assembly for the development of a new instrument for pin diversion detection

In this paper, we discuss an accurate and fast software tool (INSPCT-S, Inspection of Nuclear Spent fuel-Pool Calculation Tool, version Spreadsheet) developed for calculation of the response of fission chambers placed in a spent fuel pool, such as Atucha-I. INSPCT-S is developed for identification of suspicious regions of the pool that may have missing or substitute assemblies. INSPCT-S uses a hybrid algorithm based on the adjoint function methodology. The neutron source is comprised of spontaneous fission, ({alpha}, n) interactions, and subcritical multiplication. The former is evaluated using the ORIGEN-ARP code, and the latter is obtained with the fission matrix (FM) formulation. The FM coefficients are determined using the MCNP Monte Carlo code, and the importance function is determined using the PENTRAN 3-D parallel Sn code. Three databases for the neutron source, FM elements, and adjoint flux are prepared as functions of different parameters including burnup, cooling time, enrichment, and pool lattice size. INSPCT-S uses the aforementioned databases and systems of equations to calculate detector responses, which are subsequently compared with normalized experimental data. If this comparison is not satisfied, INSPCT-S utilizes color coding to identify the suspicious regions of a spent fuel pool. (authors)

Young Ham

Papers

Monte carlo characterization of pressurized water reactor spent fuel assembly for the development of a new instrument for pin diversion detection

Development of INSPCT-S for Inspection of Spent Fuel Pool

A methodology for determination of detector response for inspection of a spent fuel pool

Partial Defect Testing of Pressurized Water Reactor Spent Fuel Assemblies

University of cincinnati and LLNL collaboration : PWR fuel pin diversion study