Criticality and shielding
A proven track record in criticality and shielding supports customers with complex and challenging nuclear transports.
The NTS team provides an all-round service for customers including radiation shielding, dose advice and criticality safety advice to support the design and licensing of nuclear transport containers and vessels.
We are specialists in transport criticality and shielding, and represent decades of experience, carrying our assessments and advising customers on how to best address their individual transport challenge.
Criticality assessments
NTS works with customers across the UK nuclear industry to advise them on criticality safety associated with transport movements.
We are able to undertake criticality assessments of all fissile materials, fuel types and materials including unirradiated and irradiated materials, wastes, metals, oxides, carbides, plutonium, uranium and MOX fuels using MONK.
Customers value the capability of the NTS transport criticality and shielding team because all their needs can be met under one roof. No one else offers the same complete lifecycle service specialising in nuclear transport.
Shielding
Our shielding assessors provide transport solutions that are designed to ensure all staff and the public are protected from the harmful effects of ionising radiation exposure. They work hand in hand with our engineers who specify and design packages for the safe transport of nuclear material.
NTS provides shielding and dose solutions for a range of radiation sources with the capability to run complex calculations using MCNP, Attila, MCBEND, RANKERN, and MicroShield. We are adept at communicating such complex information to customers and other stakeholders to inform the optimum transport strategy.
Criticality and shielding skills in transport requires specialist expertise. NTS invests in recruiting, maintaining and developing skills to ensure the UK retains this core competency.
Independent peer review
A key requirement for any nuclear material transport in the UK is an independent peer review of the complete safety case for applications requiring UK competent authority approval. It’s something the Office for Nuclear Regulation (ONR) recommends.
NTS can support customers with such reviews on a wide range of radiation shielding and criticality safety-related topics – from detailed shielding and criticality calculations, to reviewing the logic and methodology applied to safety cases.
NTS are experienced in the application of IAEA transport regulations and industry best practice. Our aim is to always achieve the optimum transport solution for our customers which is both safe and cost-effective.
Package design safety report chapter compilation
When NTS carries out detailed technical assessments for customers, they usually form part of a larger safety case, for example a Package Design Safety Report (PDSR). A PDSR validates the safety of a package design or transport operation by demonstrating compliance with the IAEA transport regulations.
The NTS team have vast experience in summarising detailed assessments for these larger reports so they are understood easily by the customer.
Source characterisations
Source characterisation is the starting point for determining all nuclear transport solutions. The process used to derive a source term or radionuclide inventory needs to be scientifically robust, methodical, and performed in such a way that it provides the provenance to underpin further work.
NTS has experts experienced in source characterisation for transport applications. Techniques and methods we use include inventory decay, source spectra generation activation/irradiation and fuel burn-up. Access to industry codes (e.g. FISPIN, ORIGEN etc.) gives us the necessary tools to do assessments of any complexity to meet both regulator and customer needs.
Case studies
UK sealed radiation sources – delivering a new and cost-effective solution
The UK had an urgent requirement to collect a backlog of radiation sealed sources from across the country and transport them for safe disposal.
UF6 shipment – optimising capacity on a PNTL vessel
NTS shielding assessors were asked to provide an assessment to justify the shipment of 120 UX-30B transport packages on board a PNTL vessel. Timescales were short plus the vessel had only previously been licensed to carry 40 of the packages.
MOX fuel transport package – demonstrating package design innovation
The NTS M4/12 MOX fuel transport package has improved shielding and thermal performance.
‘Multiple High Standard Water Barrier’ transport package – a first for the UK
NTS were asked to help with the movement of un-irradiated fissile materials (‘Exotics’) from the site managed by Dounreay Site Restorations Ltd (DSRL).
Discover more
Package design
Designing and testing packages to transport a wide range of nuclear materials by sea, rail and road.
Package design Package licensing
A clear understanding of the transport licensing and regulatory landscape.
Package licensing
