Packaging Design and Qualification: The Experience of the CDTN/CNEN

Abstract

Since 1982 the CDTN, the Nuclear Technology Development Centre, has been designing, testing and qualifying packaging for radioactive materials. These packagings are used for the transport of radioisotopes and disposal of spent sealed sources, wastes generated in the nuclear fuel cycle and the wastes produced in the radiological accident that occurred in the city of Goiânia. For radioactive tracers and medical/industrial radioisotopes, the packagings used are cardboard and wood boxes, while the spent sealed sources are preferably conditioned in metal drums containing lead shielding and a gas absorber material. To condition and transport the wastes from the various nuclear cycle activities, metal drums and boxes are used in Brazil. For the higher active wastes from the nuclear power plant Angra I, a metallic drum in a concrete overpack is used. The wastes generated in the accident were first conditioned in the readily available packaging. Later on, more appropriate packaging was designed by the CDTN staff. CDTN has carried out a programme since 1983 to evaluate the durability of commercial drums used for waste conditioning.     

Abstract

Abstract

This article is aimed at summarising the activities related to the transport of radioactive materials carried out in Argentina and, especially, with regard to the transport of radioactive wastes. In particular, the legislation applicable within the national territory is described. Additionally, figures are provided on the features and amounts of transported radioactive materials, including radioactive wastes, concerning both the nuclear fuel cycle and activities related to their industrial and medical applications.     

Safety assessment of liquid radioactive wastes buried for a long time in deep repositories

The concepts of specific and absolute toxicity permit distinguishing in radioactive wastes belonging to different categories the particular components that present the greatest ecological danger at different stages of their disposal in repositories. It is shown that transuranium elements determine the toxicity parameter of high-and medium-level wastes only 350–400 years after initial disposal. At the present stage of operation of deep repositories, the behavior of the long-lived fission products of ⁹⁰Sr and ¹³⁷Cs is most important. For low-level wastes, the chemical and not the radioactive component is most dangerous. __________ Translated from Atomnaya énergiya,Vol. 100, No. 2, pp. 86–92, February, 2006.     

Packing and Transport of Intermediate and Low Level Wastes (ILLW): The Italian Situation

Abstract

At present, radioactive waste management in Italy involves only some limited activities for treatment and conditioning of materials classified as Low Specific Activity (LSA), mainly originating from medical and industrial (non-electric) activities. Movements of radwastes, mainly by road, constitute about 35% of the 500,000 transports of radioactive materials made in Italy each year. The packing of wastes as they are produced, and particularly the features related to the packing of wastes after treatment and/or conditioning to make them suitable for transport to the final disposal, is described.     

Qualification Tests for Packages used for Transport and Storage of Radioactive Waste (Low Activity) in INR Pitesti

Abstract

Radioactive wastes generated by the TRIGA INR research reactor are packaged according to the national and international standards and the IAEA Regulations. The technology for packaging and treatment of radioactive wastes used in this institute can be applied, prospectively, at the Nuclear Power Plant Cernavoda, after commissioning. The qualification tests (type tests) are described for packages used for transport and storage (for a long period of about 30 years) of radioactive wastes (low activity, up to 0.5068×10¹⁰ Bq per drum, or 0.164 Ci per drum). The package used is a drum manufactured in Romania industry. The type tests carried out are described i.e. compression, penetration, free fall, leaching, safety in use (biological protection), chemical and mechanical characteristics, effect on the environment, and also the results, interpretation and conclusions from the tests. As a result of the tests, Romanian technology for treatment and packaging of radioactive wastes is considered to be in accordance with IAEA Regulations.     

Qualification Tests of Packages used for Transport and Storage of Low Activity Radioactive Wastes In INR Pitesti

Abstract

Radioactive wastes generated by the TRIGA INR research reactor are packaged according to the national and international rules and standards. The technology for packaging and treatment of radioactive wastes can also be used at the Nuclear Power Plant Cernavoda. The qualification tests for the package used for transport and storage of radioactive wastes (low activity, up to 6·07 GBq (0·164 Ci) per drum) are described. The package used is a drum manufactured from 1 mm thick mild steel with the dimensions: height 915 ± 10 mm; diameter 600 ± 5 mm; volume 220 litres. To achieve adequate safety in the transport of radioactive wastes strict precautions must be taken to protect transport workers, the general public and the environment by ensuring, both in normal and in accident conditions, adequate containment and shielding of the materials, according to the IAEA Regulations for the Safe Transport of Radioactive Materials. The adequacy of the package design is therefore of primary importance, the design requirements being supplemented by careful construction, quality assurance and inspection procedures. Taking into consideration the above requirements, qualification tests for the prototype package were carried out. These tests include compression, penetration, free fall, leaching, safety in use (biological protection), checking of chemical and mechanical characteristics, and the effect of the product on the environment. Performance of these tests, and the results obtained, prove that our technology for treatment and packaging of radioactive waste is in accordance with international rules.     

Handling radwastes during rehabilitation of contaminated objects and grounds of the Kirovo-Chepetsk Chemical Works

Possible ways to rehabilitate the objects and grounds of the Kirovo-Chepetsk Chemical Works are examined. The technology for handling radioactive wastes and methods for immobilizing radioactive wastes in repositories are briefly described. Ways to eliminate radwaste repositories containing medium-level wastes with fissile substances and α-emitters are proposed. The experience gained in such work abroad is examined and the problems which must be solved to rehabilitate the objects at the Works are noted.     

Development of calculation methodology for estimation of radionuclide composition in wastes generated at Fukushima Daiichi nuclear power station

ABSTRACT

A calculation methodology for estimating the radionuclide composition in the wastes generated at the Fukushima Daiichi nuclear power station has been developed by constructing a skeleton overview of the distribution of radionuclides considering the material balance in the system and calculation flowcharts of the transportation of radionuclides into the wastes. The wastes have a distinctive feature that their level of contamination includes considerable uncertainties because the process behind the contamination with the radionuclides released from the damaged fuel during and after the accident is not yet fully understood. Here, the developed method can explicitly specify the intrinsic uncertainties as a band to be included in the estimated radionuclide composition in the wastes and can quantitatively describe the uncertainties by calibration using analytically measured data on actual waste samples collected at the site. Further studies to improve the quality of the calculation method, the introduction of a stochastic approach to describe uncertainties, and acquiring a quantitative understanding of the spatial distribution of radionuclides inside the reactor building are suggested as important steps toward reasonable and sustainable waste management as an integral part of the decommissioning of the Fukushima Daiichi nuclear power station.     

MANAGEMENT OF RADIOACTIVE WASTES IN CHINA

The policy and principles on management of radioactive wastes are stipulated.Cement solidification and bituminization unit has come into trial run.Solid radioactive waste is stored in tentative storage vault built in each of nuclear facilities.Seventeen storages associated with applications of nuclear technology and radioisotopes have been built for provinces.Disposal of low and intermediate level radioactive wastes pursues the policy of “regional disposal”.Four repositories have been planned to be built in northwest.southwest,south and east China respectively.A program for treatment and disposal of high level radioactive waste has been made.     

Environmental assessment of advanced partitioning,transmutation, and disposal based on long-term risk-informed regulation: PyroGreen

The safety of spent nuclear fuel (SNF) storage has become one of the major issues of nuclear power plant operation. Direct disposal and recycling have both been criticized by the general public due to uncertainty of the long-term safety of SNF and high level waste (HLW) repositories. To meet the goal of sustainable nuclear energy, an innovative recycling approach using pyrochemical partitioning and transmutation termed PyroGreen, which is a conceptually advanced pyrochemical partitioning flowsheet, has been proposed to eliminate the need for HLW repositories. From the previous partitioning process, PyroGreen uses a combination of hull electrorefining, reductive extraction, and selective oxidation to further decontaminate SNF and HLW into low- and intermediate level waste (LILW). This paper examines the long-term environmental performance of a geological repository that houses all of the final PyroGreen-produced wastes while describing the feasibility of PyroGreen partitioning and transmutation. The final PyroGreen wastes are evaluated based on long-term risk-informed criteria: alpha-emitting isotope concentration, heat generation, and radiation dose in the surrounding biosphere. All final wastes arising from PyroGreen are to be disposed of in a geological repository at an intermediate depth, in compliance with new International Atomic Energy Agency Safety Guide for LILW. Migration assessment found that several long-lived fission products including C-14, Cl-36, Se-79, Sn-125, and I-129 dominate the long-term dose rate, whereas transuranic elements govern the risk of an inadvertent human intrusion scenario. In order to turn entire batches of SNF from 24 light water reactors with 1000 MWe with a design life of 40 years into LILW, we determined and compared the required decontamination factors of the key radionuclides for between intermediate-depth and near-surface disposal.     

Chapter 3: Type and Quantity of Radioactive Waste Destined for Disposal

Abstract

According to the current planning status, radioactive waste with negligible heat generation is destined for storage in the Konrad waste repository in accordance with the Provisional Waste Acceptance Requirements⁽⁴⁾. Waste of this kind occurs in the nuclear fuel cycle, research, medicine and technology. In its original state, the primary wastes of this type have various forms, such as: liquids, concentrates, sludges; ion exchange resins; compressible and/or combustible solids; incompressible solids, e.g. structural material components; filters, filter candles; other types of waste. The radioactive waste is appropriately conditioned and packaged before transport to the waste disposal site. To meet the basic requirements specified in the Waste Acceptance Requirements, primary waste must be solidified, for which the most common solidifying agents are cement and concrete although bitumen is also used. Waste products in decomposing, fermenting or liquid form or which contain a significant fraction in such states are not accepted for disposal.     

The Planned Integrated Transport System for the Deep Repository in the UK

Abstract

UK Nirex Ltd is responsible for developing a deep repository for the safe disposal of intermediate and low level radioactive wastes (ILW and LLW), and is concentrating its investigations on Sellafield as a potential location. A key part of the repository development programme is a transport system to deliver packaged wastes from sites elsewhere in the UK. The transport system must be able to handle a range of standard waste packages, and all transport through the public domain must comply with the IAEA Transport Regulations. Two design concepts have been developed for re-usable shielded transport containers for ILW, which are predicted to withstand accidents at least as severe as the IAEA Type B test conditions. Assessment, testing and further development of both concepts continues, with a view to selecting one for quantity production. Nirex is working closely with various organisations to establish the optimum transport routes for a potential repository at Sellafield. The current policy is that rail transport shall be used wherever practical for the transport of waste to the repository, although some road transport may also be required; the company has assessed a range of options. A Probabilistic Safety Assessment of the proposed transport operations has predicted that the radiological risks are expected to be extremely low, reflecting the adequacy of the packaging concepts. In addition, Nirex has identified a suitable transport emergency plan to deal with any unforeseen events.     

LLW Transport by IP-2 Packaging

Abstract

As the Japanese nuclear power plants are located on the sea coast, the optimal system for LLW transport consists of sea and land modes. A special ship ‘Seiei Mam’ was built to transport the LLW from nuclear power plants to the LLW Burial Centre in Rokkasho-mura, Aomori Prefecture, and dedicated trucks were prepared to transfer the LLW from the receiving wharf to the Burial Centre. Containers were developed to transport LLW drums efficiently and were designed and tested to meet the IP-2 packaging requirements. Of such containers 3000 have been used since 1992 and the safe transport of LLW has been demonstrated by means of the IP-2 packagings.     

Extraction of radioactive wastes and liquidation of old repositories at the Russian Science Center Kurchatov Institute

The salient features of the organization and execution of the work performed to remove radioactive wastes from and rehabilitate ten old repositories located on a special site of the Institute, which were distinguished by their design and the form and composition of the wastes contained in them, are described. The old repositories were located close to a housing development, so that special attention was devoted to the choice of technologies and technical means used for the rehabilitation. The technical approach and the sequence of operations are presented, and the technology and technical means are described. The problems of providing the proper technological equipment for this work are analyzed. __________ Translated from Atomnaya énergiya, Vol. 103, No. 2, pp. 129–133 August, 2007.     

Boxes for the Transport and Disposal of Low Level and Decommissioning Intermediate Level Radioactive Wastes

Abstract

UK Nirex Ltd is developing specifications for standard containers for the packaging of low and intermediate level radioactive wastes for disposal in a deep underground repository. The methodology used for selection of the dimensions and payloads of boxes for LLW and decommissioning ILW are described, and design features for handling the boxes are also briefly discussed. It must be emphasised that the results of this study are as yet preliminary, and may change in the light of the evolving system design for waste packaging, storage, transport and disposal.     

The French Nuclear Safety Authority's Experience with Radioactive Transport Inspection

Abstract

About 300,000 radioactive material packages are transported annually in France. Most consist of radioisotopes for medical, pharmaceutical or industrial use, but the nuclear industry deals with the transport of fuel cycle materials (uranium, fuel assemblies, etc.) andwaste from power plants, reprocessing plants and research centres. France is also a transit country for shipments such as spent fuel packages from Switzerland or Germany, which are bound for Sellafield in the United Kingdom. The French nuclear safety authority(DGSNR, Directorate General for Nuclear Safety and Radioprotection) has since 1997 been responsible for the safety of radioactive material transport. This paper presents DGNSR's experience with transport inspection: a feedback of key points based on 300 inspections achieved during the past 5 years is given.     

Inspection and preparation for liquidation of old radwaste repositories at the Russian Science Center Kurchatov Institute

Efforts to develop design materials and preparations for liquidation of old radwaste repositories at the Russian Science Center Kurchatov Institute have revealed problems due to the lack of archived information on the salient structural features of the repositories and the wastes placed there as well as due to the inadequate development of the technical and technological support base for restoration work. The technical approach implemented during the preparation for liquidation of the repositories is described. The sequence of operations is presented, and the technological and technical means are described. The problems of the technological support for inspection of the repositories are analyzed. __________ Translated from Atomnaya énergiya, Vol. 102, No. 6, pp. 374–377, June, 2007.     

Challenges in the renewal of the Swedish sea transport system

Abstract

Since 1985, SKB has successfully operated a sea transport system for transport of spent nuclear fuel and radioactive waste to the intermediate storage facility, Clab and the final repository, SFR, in Sweden. The main components in the system are the ship M/S Sigyn, transport casks for spent fuel and core components, IP2 containers and terminal vehicles.