Development of Chinese database on safe transport of radioactive materials

Abstract

The paper introduces the newly established Chinese database, which is still in its initial stage of development, on the safe transport of radioactive materials in China. The database will collect data on several transport routes in China that presently have comparatively large transport volume. The database mainly includes data on transport management, transport incidents/accidents and road circumstances, etc. This will provide a data shared plane for departments in charge of packaging and transport and for research institutes. Areas of improvements in the future work are also mentioned at the end of the paper.     

Comparison of collective dose in India and USA owing to transport of radioactive material by road

Abstract

This paper estimates probable collective doses owing to transport of radioactive material by road mode in India and the USA for an identical hypothetical case under respective transport conditions for the two countries, using the INTERTRAN2 computer code. The differences observed in the transport conditions in the two countries are reflected in the DNORM input parameters for the incident free transport conditions of transport and the accident rates. Owing to differences in the parameter values, it is found that the estimated probable collective dose values owing to transport of radioactive material by road mode for India are much higher than those for USA. Sensitive parameters are identified which contribute maximum to the estimated probable collective dose.     

Safe transport of radioactive material in Brazil

Abstract

The objectives of this article are to briefly present an updated review of the regulatory framework and activities related to the transport of radioactive material in Brazil, to provide an analysis of the appraisal service performed by the International Atomic Energy Agency (IAEA) in 2002 and to identify questions that require action plans from the Brazilian Nuclear Energy Commission (CNEN), including those actions which will involve neighbouring countries regulatory authorities.     

Criticality risks during transportation of spent nuclear fuel

Abstract

A probabilistic risk assessment (PRA) quantifies the frequency of criticality accidents during railroad transport of spent nuclear fuel casks (SFCs) in the USA. It evaluates the likelihood that undetected errors in fuel selection and/or fuel handling could result in a misloaded SFC susceptible to a criticality event following an accident during rail transport of the cask. The PRA shows that existing fuel burnup records and formal procedures for loading a SFC make the likelihood of shipping a misloaded SFC on the order of 2·6 × 10^–6 per SFC. When combined with historical evidence regarding train accidents and an estimate of the likelihood that an accident could breach and submerge a SFC, the calculated frequency of criticality is below 2 × 10^–12 over the 11 000 shipments that would be required to ship the spent fuel inventory generated by the current US fleet of nuclear reactors, assuming that they each operate for 60 years.     

Transport of radioactive material in South Africa

Abstract

This paper aims to present an overview of the activities related to the transport of radioactive material in South Africa. In particular, the applicable legislation, the scope of authority and regulatory functions of the competent authority (CA) is discussed. The categories of radioactive materials transported and the packaging requirements for the safe transport of these radioactive materials are also described.     

Radioactive and nuclear material transport security: awareness and application of new recommendations

Abstract

Transport of radioactive and nuclear material is highly regulated and transport safety regulations have been in effect for decades. International nuclear material transport security has been governed for many years on the basis of a binding international convention, the 'Convention for the physical protection of nuclear material', and its supporting document 'The physical protection of nuclear material and nuclear facilities' INFCIRC/225, revision 4 (corrected). On the other hand, transport security guidance for the radioactive material was published in 2008 by the International Atomic Energy Agency (IAEA) as an implementing guide, 'Security in the transport of radioactive material', nuclear security series no. 9, and is just now being implemented in many countries. Experience in implementing the radioactive material transport security guidance is being gained by countries as they make decisions on which specific security provisions to require, provide training to their regulatory staff and licensees, and begin reviewing and approving transport security plans. This experience has led to the development of practical approaches that minimise impacts as the guidance is put into practice. The nuclear material transport security recommendations in INFCIRC/225 are in the process of being revised to update them to address the current threat environment and to incorporate recommendations based on the recent amendments made to the Convention. INFCIRC/225, revision 5 will be a recommendation level document in the IAEA nuclear security series of documents. The interface between the nuclear and radioactive material transport security documents is important in order to ensure that appropriate security measures, based on both the nuclear and radioactive properties of the material being transported, are defined and implemented. This paper provides up to date information on the development of the IAEA transport security documents and presents information on implementation of the radioactive material transport security recommendations. It explains how the documents interface with each other and provides examples of how they should both be used in defining transport security requirements for shipments.     

Threat analysis for transport of radioactive material using morphological analysis

Abstract

The Swedish Defence Research Agency (FOI) was commissioned by the Swedish Nuclear Power Inspectorate to carry out a pilot study which would serve as the basis for a revised set of regulations regarding physical protection and administrative routines for the transport of radioactive material. The pilot study was to develop a prototype model by which a comprehensive threat analysis could be carried out. The study employed computer aided morphological analysis, which is a flexible, non-quantified modelling method developed at FOI during the 1990s. The paper will present the methodological foundations of morphological analysis and present the prototype models involving general threat scenarios, transport situations, antagonists and strategic measures.     

Some views on 2 year review/revision cycle of IAEA regulations for safe transport of radioactive material

Abstract

In the past the International Atomic Energy Agency (IAEA) transport regulations have normally been reviewed or revised within a 10 year cycle to support changes in transport operations arising from administrative and technical developments and new knowledge in fields concerning the transport of radioactive material. Beginning in 2003, consistent with the time schedules of the United Nations (UN) Sub-Committee of Experts on the Transport of Dangerous Goods and of the relevant international modal organisations, a regular 2 year review of the IAEA transport regulations was established, with a view to issuing a revised or amended edition as necessary. This paper describes the process of the review/revision itself, the transfer to the regulations of the UN and the modal organisations as well as implementation within the legislation of the member states. The advantages and disadvantages of the more frequent process are analysed: on the one hand harmonisation with the UN and the modal organisations, on the other hand a possible lack of sufficient stability in the regulations themselves. The need for the 'Schedules of requirements for the transport of specified types of radioactive material consignment', which are an integral part of the IAEA transport regulations TS-R-1 but which from 1 January 2005 are no longer a part of the international modal regulations, is discussed.     

Terrorism and maritime shipment of nuclear material

Abstract

Opponents of the nuclear industry often claim that material in transit is vulnerable to attack by terrorist groups who might seek to take the cargo and make a bomb, or otherwise cause a radiological incident. This paper lays out a range of conceivable objectives or attack scenarios in the context of maritime transportation and examines these in the light of what is known of the relevant security arrangements. It concludes that these arrangements provide a very substantial deterrent to any attempt at diversion or sabotage and that any such attempt would have little prospect of success, beyond the immediate media impact of whatever might have occurred.     

New generation standard nuclear material container

Abstract

Nuclear Filter Technology (NucFil) is working with the Los Alamos National Laboratory (LANL) to design a nuclear material storage container that complies fully with the requirements of DOE M 441·1-1. LANL provided NucFil with a specification that outlines requirements to comply with the manual, as well as to satisfy specific needs of their own. NucFil has taken this specification and designed a container known as the new generation standard nuclear material container (NG SNMC). The premise of the design is a simple, robust container that is easy to use. The sealing mechanism is a single large cross-section, low durometer o-ring. The large cross-section provides a tight seal that has enough elastic rebound to compensate for any distortion of the sealing faces after a potential drop. The low durometer keeps the force required to open and close the container low. Once compressed, the seal is kept in place by a bayonet style closure that is locked in place by a positive mechanical engagement. The components of the container exposed to the load are manufactured of corrosion resistant 316L stainless steel. The container has a filter made of a heat resistant ceramic fibre to retain particles after a fire, and a water resistant membrane to keep moisture out of the container. Pewter shielding can be attached and is latched in place. These features are present in all seven sizes of the NG SNMCs, including 1, 3, 5, 8 and 12 quart and 5 and 10 gallon.     

Radiological impact of transport of radioactive material in UK by road and rail

Abstract

A survey has been carried out on the transport of radioactive materials by road and rail in the UK by the Health Protection Agency's Radiation Protection Division. This survey, carried out in 2004, is the latest in a series of periodic studies on the transport of radioactive materials by all modes of transport. Questionnaires were sent to hospital departments, radionuclide manufacturers, suppliers, and carriers, and to the nuclear and other industries, in order to obtain data on shipments of radioactive materials. Visits were made to hospitals, suppliers, carriers and some railway premises in order to observe working practices and radiological surveys were made while packages were handled. Assessments of individual doses to workers and members of the public were made, and occupational dosimetry data were also obtained. It was found that ～500 000 package movements take place by road annually in the UK, with ～4000 package movements annually by rail. Radiation doses to most transport workers are low, with an average dose of 0·6 mSv to general workers transporting medical and industrial sources. Doses to individual members of the public are very low, with average annual doses of less than 0·02 mSv.     

IRSN's experience feedback list for assessment of transport package design safety reports

Abstract

Since 1996, the Institute for Radiation Protection and Nuclear Safety (IRSN), the technical support organisation of the French Competent Authority for the safety of transport of radioactive materials, has recorded the list of the difficulties most frequently encountered during the assessment of the safety reports of package designs. This experience feedback list takes into account the most recent evolutions of the regulations and the latest technological knowledge. For instance the safety reports should include the analysis of the most unfavourable configurations such as the 1 m free drop onto the bar when the package is in oblique position, the 9 m drop test of a package with slapdown, the thermal dissipation under a tarpaulin or canopies, the brittle fracture analysis at –40°C. IRSN's experience feedback list for transport package designs, which is published annually, is used as a guide by applicants to improve their package design safety reports and by IRSN for their assessments. Recently, it has been integrated in the French transport applicant guide and in the European technical guide for drafting the package design safety reports.     

Scale model impact limiter in type assessment of radioactive material transport packages

Abstract

In Germany, the Federal Institute for Materials Research and Testing (BAM) is the competent authority for the mechanical and thermal design safety assessment of transport packages for radioactive material according to IAEA regulations. The combination of experimental and numerical safety proof forms the basis for a state of the art evaluation concept. Reduced scale models are often used in experimental investigation for design assessment of transport packages corresponding to IAEA regulations. This approach is limited by the fact that a reduced scale model cask can show different behaviours from a full scale cask. The paper focuses on the peculiarities of wood filled impact limiter of reduced scale models. General comments on drop testing with reduced scale models are given, and the relevant paragraphs of the IAEA regulations and Advisory Material are analysed. Possible factors likely to influence the energy absorbing capacity of wood filled impact limiting devices are identified on the basis of similarity mechanics. Among possible significant influence factors on the applicability of small scale models are strain rate and size effects, failure mechanisms, underground compliance, gravitational and friction effects. While it was possible to derive quantitative estimations for the influence of strain rate, size effects and target compliance, it was not possible to evaluate the influence of compression mechanisms and gravitation. In general, if reduced scale models are used in proof of safety, uncertainties increase in comparison with full scale models. Additional safety factors to exclusively cover the uncertainties of reduced scale model testing have to be demanded. The possible application of reduced scale models in regard to crucial aspects for proof of safety has to be analysed critically.     

Assessing consequences of nuclear material transport sabotage per use of armour piercing weapon

Abstract

In order to predict the consequences of a sabotage act directed against a transport of nuclear material, the present paper is an attempt to put together some components of an approach dedicated to the assessment of the release produced when using a perforating or cutting device to spill out the content of the cask. The category of threat studied here is defined especially with regard to its objective: the objective of sabotage is to instantaneously create a radioactive source term capable of polluting a more or less important area including the vicinity of the target. This definition makes the difference with theft or diversion threats where the material is stolen and taken away from where it has been removed. The work accomplished and reported in this paper is in keeping with the general pattern of the multiyear programme of IRSN where the resistances of various casks to various threats are studied. This paper is structured in two parts. In the first part, the authors summarise as a whole the question of estimating the release after perforation and give a short review of past studies on the subject. All this work has motivated the development of an approach. The approach developed and used at IRSN is introduced by the statement of a generic problem. Then the authors identify all the influent parameters which need to be addressed. The most seducing aspect of the approach is the fact that it relies on only five parameters: the five parameters relate to the energy sources capable of moving the material from the inside to the outside, the cask resistance and the release mechanisms and physics. The authors have not included any numerical example in this paper due to the evident sensitivity of such material.     

Modelling of release of particulate material from transport containers

Abstract

The Nuclear Decommissioning Authority (NDA) is developing a family of Standard Waste Transport Containers (SWTCs) for the transport of unshielded intermediate level radioactive waste packages. The SWTCs are shielded transport containers designed to carry different types of waste packages. The combination of the SWTC and the waste package is required to meet the regulatory requirements for Type B packages. One such requirement relates to the containment of the radioactive contents, with the IAEA Transport Regulations specifying release limits for normal and accident conditions of transport. In the impact tests representing accident conditions of transport, the waste package will experience significant damage and radioactive material will be released into the SWTC cavity. It is therefore necessary to determine how much of this material will be released from the cavity to the external environment past the SWTC seals. Typical assessments use the approach of assuming that the material will be evenly distributed within the cavity volume and then determining the rate at which gas will be released from the cavity, with the volume of radioactive material released with the gas based on the concentration of the material within the cavity gas. This is a pessimistic approach as various deposition processes would reduce the concentration of gas-borne particulate material and hence reduce their release rate from the SWTC. This paper assesses these physical processes that control the release rate and develops a conservative methodology for calculating the particulate releases from the SWTC lid and valve seals under normal and accident conditions of transport, in particular:

a) the flows within the SWTC cavity, especially those near the cavity walls;

b) the aerodynamic forces necessary to detach small particles from the cavity surface and suspend them into the cavity volume;

c) the adhesive forces holding contaminant particles on the surface of a waste package;

d) the breakup of waste material upon impact that will determines the volume fraction and size distribution of fine particulate released into the cavity.

Three mechanisms are specifically modelled, namely Brownian agglomeration, Brownian diffusion and gravitational settling, since they are the dominant processes that lead to deposition within the cavity and the easiest to calculate with much less uncertainty than the other deposition processes. Calculations of releases under normal conditions of transport concentrate on estimating the detachment of any waste package surface contamination by inertial and aerodynamic forces and show that very little of any contamination removed from the waste package surface would be released from the SWTC. Under accident conditions of transport, results are presented for the fraction released from the SWTC to the environment as a function of the volume fraction of the waste package contents released as fine particulate matter into the SWTC cavity. These show that for typical release fractions of 10^-6 to 10^-8 for the release of radioactive material from waste packages into the SWTC cavity, the release fraction of the waste package inventory from the SWTC of typically 10^-9 to 10^-10. Hence, the effective decontamination factor provided by the SWTC is 10² to 10³. Whilst this analysis has been carried out specifically for the SWTC carrying waste packages, it is applicable to other arrangements and its use would reduce the high degree of pessimism used in typical containment assessments, whilst still giving conservative results.     

Safety of ocean shipments of plutonium between Europe and Japan

Abstract

Sandia National Laboratories (SNL) has conducted an extensive study of emergency response planning applicable to sea transport of plutonium for the Japan Nuclear Cycle Development Institute (JNC). This work covered four separate areas to better define the accident environment for long range sea transport of nuclear materials. A probabilistic safety analysis evaluated technical issues for the transport of plutonium between Europe and Japan. An engine room fire aboard a purpose built ship was used to analyse the vulnerability of plutonium packaging designed to International Atomic Energy Agency (IAEA) standards. A comprehensive corrosion study estimated the time required for sea water to breach a containment boundary in submerged generic plutonium packaging. A survey of worldwide commercial recovery capabilities provided a compilation of information on the capabilities of salvaging high value cargo from sunken ships. This paper addresses salvage modes from harbour depths to the deepest ocean trenches. Previous studies (J. L. Sprung et al., SNL reports SAND98-1171/1 and SAND98-1171/2, May 1998) included a probabilistic risk assessment of the overall safety, source term evaluations and finite element structural dynamics calculations to determine the effects of ship to ship collisions on nuclear material containers and the effects of ship fires on transport packaging as determined by actual fire experiments conducted on board a test ship. The previous studies, together with this work, form a comprehensive technical basis that encompasses the overall safety of sea transport of plutonium between Europe and Japan. Based on these technical analyses, transport of nuclear materials by sea in Type B packaging, approved in accordance with US Nuclear Regulatory Commission (NRC) and IAEA regulations, and carried in purpose built ships with adequate surveillance, has a very high degree of safety for the failure modes studied. Non-purpose built ships do not have the redundancy in safety features provided by the newer purpose built ships. However, SNL studies on non-purpose built ships have shown accident environments to be within NRC and IAEA regulatory assumptions for Type B packaging. These studies were carried out for both structural ship to ship collisions and engine room fires by analysis (for the collisions) and direct experimentation and analysis (for the fires). Thus, land transport mode regulations are applicable for sea transport accident conditions.     

不同能量加载条件下核材料放射性气溶胶特征分析

通过开展一系列不同爆炸能量加载条件下的核材料爆炸转化实验,结合放射性分析和化学分析等方法,得到爆炸后放射性气溶胶转化份额和粒径分布等重要信息。实验结果表明,爆炸产生的气溶胶粒子以中小粒径为主且粒度分布范围较广,其放射中位空气动力学直径主要集中在3.5~7.0μm之间,几何标准差介于3~4μm之间;炸药爆炸能量对核材料的气溶胶产生份额有着十分重要的影响,爆炸能量越大,对应气溶胶转化份额也越高。该项研究成果可为开展重大核材料爆炸事故场景下的放射性污染分布和人员受辐照危害评估提供重要的技术依据。     

Ten years of Romanian experience on risk assessment owing to radioactive materials transport in Romania

Abstract

The transport of radioactive materials is a very important problem considering the potential risks and radiological consequences in carrying out the present activity. Based on the International Atomic Energy Agency (IAEA)'s Safety Standard TS-R-1 (1996 edition, as amended 2003), Romanian National Nuclear Regulatory Body – Romanian National Commission for Nuclear Activities Control (CNCAN) was adopted and implemented by act no. 374/October 2001, the safety regulations for the transport of radioactive materials in Romania under the title 'Fundamental regulations for a safe transport of radioactive materials, in Romania'. The present paper will present the main sources of radioactive materials in Romania, their transport routes with a particular interest paid to the radioactive wastes. Hypothetical scenarios for specific problems related to the identification and evaluation of the risks and potential radiological consequences associated with the transport of radioactive materials in Romania, for all these situations: routine transport (incident free) and possible accidents.