English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

The purpose of nondestructive assay in the context of nuclear safeguards isto precisely verify the declared mass of a sample of nuclear material in anoninhibitive amount of time. 237Np is a proliferation concern, and thecapacity to efficiently assay samples of it is a missing piece in theverification and safeguards toolbox. The material is subject to the samesafeguards as 235U, is reportable in gram quantities, and is classified as"other nuclear material" according to the United States Department of Energy.Given that 3000 kg of 237Np is annually produced in the US and the bare spherecritical mass is 40-60 kg, it is desirable to augment the safeguards toolboxwith a system capable of distinguishing 10 g of 237Np in a 20-minutemeasurement. One measurement modality is neutron multiplicity counting, whichrelates the detected multiplicity count rates to the amount of fissionablematerial. Prior simulation work shows that an organic scintillator-basedmultiplicity counter can achieve the design criteria, whereas the flagship3He-based system, the Epithermal Neutron Multiplicity Counter, requires muchlonger measurement times to achieve the same precision. In this work,simultaneous measurements of a 6-kg sphere of 237Np by organic scintillator-and 3He-based systems are used to confirm the trends in the simulation study;the organic scintillator-based system achieves 1% uncertainty in the neutrondouble multiplicity rate on the order of minutes, while the 3He-based systemrequires days to reach the same precision. In conclusion, the InternationalAtomic Energy Agency should consider the development and deployment of anorganic scintillator-based multiplicity counter

Measured Nondestructive Assay of $^{237}$Np Using Organic Scintillators and Active Neutron Multiplicity Counting