The Radioactive Waste Disposal Facility (RWDF) Buryakovka was constructed in 1986 as part of the intervention measures after the accident at Chernobyl NPP (ChNPP). Today, the surface repository for solid low and intermediate level waste (LILW) is still being operated but its maximum capacity is nearly reached. Long-existing plans for increasing the capacity of the facility shall be implemented in the framework of the European Commission INSC Programme (Instrument for Nuclear Safety Co-operation). Within the first phase of this project, DBE TECHNOLOGY GmbH prepared a safety analysis report of the facility in its current state (SAR) and a preliminary safety analysis report (PSAR) for a future extended facility based on the planned enlargement. In addition to a detailed mathematical model, also simplified models have been developed to verify results of the former one and enhance confidence in the results. Comparison of the results show that — depending on the boundary conditions — simplifications like modeling the multi trench repository as one generic trench might have very limited influence on the overall results compared to the general uncertainties associated with respective long-term calculations. In addition to their value in regard to verification of more complex models which is important to increase confidence in the overall results, such simplified models can also offer the possibility to carry out time consuming calculations like probabilistic calculations or detailed sensitivity analysis in an economic manner.

Large volumes of radioactive waste were urgently buried in the Chernobyl Exclusion Zone (ChEZ) in the aftermath of the 1986 accident. Twenty-six years later, decisions must be taken about whether and how to remediate these sites. An attempt to resolve two key issues is described here: 1. How to assess the hazards posed by these facilities, recognizing that, for the foreseeable future, the Chernobyl Exclusion Zone will remain under institutional control? and 2. What standards to apply in deciding the extent of remediation? This paper presents an examination of the issues and proposes a simple decision-making process.

On 26 April 1986, the worst nuclear power plant accident in history occurred at the Chernobyl plant in Ukraine (then part of the Soviet Union). The destruction of Unit 4 sent highly radioactive fallout over Belarus, Russia, Ukraine, and Europe. The object shelter — a containment sarcophagus — was built in November 1986 to limit exposure to radiation. However, it has only a planned 25-year lifespan and would probably not survive even a moderate seismic event in a region that has more than its share of such events. It was time to take action. One of the largest tasks that are in progress is the design and construction of the New Safe Confinement (NSC). The NSC is an engineered enclosure for the entire object shelter that includes a suite of process equipment. The process equipment will be used for the dismantling of the destroyed Chernobyl Nuclear Power Plant Unit. One of the major mechanical handling systems to be installed in the new safe confinement is the Main Cranes System. The planned decontamination and decommissioning or dismantling activities will require the handling of heavily shielded waste disposal casks containing nuclear fuel as well as lifting and transporting extremely large structural elements. These activities, to be performed within the new safe confinement, will require large and sophisticated cranes. The article will focus on the current progress of the new safe confinement and of the main cranes system for the decommissioning or dismantling activities.

During the operation of nuclear reactors important volume of liquid and solid radioactive wastes are generated, which, in normal conditions, becomes processed by stationary equipment by different methods to minimize their volume and then sent to specially constructed storages. The cases of accidents of Chernobyl and Fukushima showed that the localization of rejected big quantity of radioactive wastes is a prior problem for their further processing by stationary equipment. In this regard it is very important the processing of radioactive wastes on the contaminated areas to localize them by mobile equipment based on the efficient technologies. RADEON-NWM new technology allows resolving this problem. This technology is compact, completely automated, which makes possible to assemble it on a standard 40-ft by 7-ft trailer driven by heavy-duty truck. The new technology is fully elaborated, the necessary tests are conducted.

In this paper we report the results of pilot tests of flocculation/precipitation setup for dust-suppressor (DS) and transuranic elements (TUE) removal from wastewaters of Chernobyl Nuclear Power Plant (ChNPP), including those of the Object “Shelter”. Tests were performed on the pilot unit (PU), which included service tank, precipitation tank, and accumulation tank, 300 dm 3 each, connected with pipelines with dosing and pumping equipment, and throttle valves providing controlled dosing, mixing, precipitation and mechanical filtration of radioactive wastewaters under different conditions. The reagent compositions used in pilot tests were based on coagulant POLYPACS-30 LF (aluminum polyoxychloride), synthetic cationic flocculants Besfloc K6634, K510CA, K6732 («Kolon Life Science, Inc», South Korea) varying in molecular weight and charge density, and natural cationic flocculant «Chitofloc» (Institute of Chemistry FEBRAS, Russia). The following wastewater parameters were controlled during the pilot tests: pH, dry residue, oxygen consumption, total α- and β-activity, isotope composition, optical density and DS content. The precipitation setup demonstrated lower efficiency DS removal from evaporator concentrates due to high ionic strength suppressing the electrostatic interactions between coagulants/flocculants and oppositely charged colloids of DS and TUE. The residual DS concentration was below 1 mg/L that corresponds to decontamination factor above 300 for the drainage water samples tested. The chitosan-based “Chitofloc” flocculant appeared to be the reagent which was the least sensitive to negative effect of ionic strength; however, the decontamination factor in DS removal was not higher than 5 due to suppressing of electrostatic interactions in high salinity media. Analysis of α-activity of water samples after flocculation/mechanical filtration revealed that TUE were not detected in the drainage water samples with DS content reduced to 2 mg/L that corresponds to TRU decontamination factor above 10000 and confirms immobilization of TUE in DS precipitate.

The impact analysis of low doses of ionizing radiation on the breathers in natural populations is an important part of radiobiological studies of non-human biota. The main aim of our studies was to investigate some cytogenetic, morphological and reproductive rates of the common reed (Phragmites australis (Cav.) Trin. ex. Steud.) from different water bodies within the Chernobyl accident exclusion zone. The absorbed dose rate for littoral emergent plants in sampling water bodies was varied from 1.3E−02 to 1.6E−01 Gy/h. The rate and main types of chromosome aberrations in roots meristems, morphological damages in seed germs, as well as rates of germinating ability and power were analyzed. There were registered rather low rate of germinating ability (14–48%) and germinating power (<1) of seeds from all sampling water bodies with high levels of radioactive contamination in comparison to control ones. Against the general suppressed background the effect of relative stimulation of more affected seeds was observed. With increase of absorbed dose in range of 1.3E−02–1.6E−01 Gy/h the number of germinated seeds was increased. At the same time the number of morphological damages of seeds was increased as well. There was determined the positive correlation between absorbed dose rate and chromosome aberration rate in roots of the common reed from sampling water bodies. The highest rate of chromosome aberrations (up to 17%) were registered in plants with high level of morphological deviations in seeds germs. The data obtained from the complex analysis of natural populations of the common reed from the radioactive contaminated water bodies testify about rather high level of genetic efficiency of low doses of long-term exposure.

Through the Global Partnership the UK continues to make a significant contribution to improve national and global security. Over the past year the UK has continued to implement a wide range of projects across the breadth of its Global Partnership Programme. As well as ensuring the Programme is robust and capable of dealing with new challenges, the UK has cooperated with other donor countries to help them progress projects associated with submarine dismantling, scientist redirection, enhancing nuclear security and Chemical Weapons Destruction. The Global Partnership, although only five years old, has already achieved a great deal. Some 23 states, plus the European Union, are now working closer together under the Global Partnership, and collectively have enhanced global regional and national security by reducing the availability of Weapons of Mass Destruction (WMD) materials and expertise to both states of concern and terrorists. Considerable progress has already been made in, for example: • Improving the security of fissile materials, dangerous biological agents and chemical weapons stocks; • Reducing the number of sites containing radioactive materials; • Working towards closure of reactors still producing weapon-grade plutonium; • Improving nuclear safety to reduce the risks of further, Chernobyl style accidents; • Constructing facilities for destroying Chemical Weapons stocks, and starting actual destruction; • Providing sustainable employment for former WMD scientists to reduce the risk that their expertise will be misused by states or terrorists. By contributing to many of these activities, the UK has helped to make the world safer. This paper reports on the UK’s practical and sustainable contribution to the Global Partnership and identifies a number of challenges that remain if it is to have a wider impact on reducing the threats from WMD material.

It is considered the efficacy of decisions concerning remedial actions when of-site radiological monitoring in the early and (or) in the intermediate phases was absent or was not informative. There are examples of such situations in the former Soviet Union where many people have been exposed: releases of radioactive materials from “Krasnoyarsk-26” into Enisey River, releases of radioactive materials from “Chelabinsk-65” (the Kishtim accident), nuclear tests at the Semipalatinsk Test Site, the Chernobyl nuclear accident etc. If monitoring in the early and (or) in the intermediate phases is absent the decisions concerning remedial actions are usually developed on the base of permanent monitoring. However decisions of this kind may be essentially erroneous. For these cases it is proposed to make retrospection of radiological data of the early and intermediate phases of nuclear accident and to project decisions concerning remedial actions on the base of both retrospective data and permanent monitoring data. In this Report the indicated problem is considered by the example of the Chernobyl accident for Ukraine. Their of-site radiological monitoring in the early and intermediate phases was unsatisfactory. In particular, the pasture-cow-milk monitoring had not been made. All official decisions concerning dose estimations had been made on the base of measurements of 137Cs in body (40 measurements in 135 days and 55 measurements in 229 days after the Chernobyl accident). For the retrospection of radiological data of the Chernobyl accident dynamic model has been developed. This model has structure similar to the structure of Pathway model and Farmland model. Parameters of the developed model have been identified for agricultural conditions of Russia and Ukraine. By means of this model dynamics of 20 radionuclides in pathways and dynamics of doses have been estimated for the early, intermediate and late phases of the Chernobyl accident. The main results are following: • During the first year after the Chernobyl accident 75–93% of Commitment Effective Dose had been formed. • During the first year after the Chernobyl accident 85–90% of damage from radiation exposure had been formed. During the next 50 years (the late phase of accident) only 10–15% of damage from radiation exposure will have been formed. • Remedial actions (agricultural remedial actions as most effective) in Ukraine are intended for reduction of the damage from consumption of production which is contaminated in the late phase of accident. I.e. agricultural remedial actions have been intended for minimization only 10% of the total damage from radiation exposure. • Medical countermeasures can minimize radiation exposure damage by an order of magnitude greater than agricultural countermeasures. • Thus, retrospection of nuclear accident has essentially changed type of remedial actions and has given a chance to increase effectiveness of spending by an order of magnitude. This example illustrates that in order to optimize remedial actions it is required to use data of retrospection of nuclear accidents in all cases when monitoring in the early and (or) intermediate phases is unsatisfactory.

This paper describes the work covered and experience gained in the first two years of operation of DERC, a Centre for Decommissioning and Environmental Remediation in the Highlands of Scotland. The Centre is a unique development which was set up to teach nuclear decommissioning as a separate discipline, address the problem of a declining skills base in the field of nuclear technologies and to take advantage of the unique and exceptional innovative, technical and research opportunities offered through the decommissioning of Britain’s fast reactor site at Dounreay. The Centre is an offshoot from North Highland College which is a member of UHI, the University in embryo of the Highlands and Islands. The Centre currently supports ten PhD students completing various diverse projects mainly in the field of nuclear environmental remediation. In addition there are a number of full and part time MSc students who participate in NTEC (Nuclear Technology Education Consortium) a consortium of British Universities set up specifically to engender interest and skills in nuclear technology at postgraduate level. At undergraduate level, courses are offered in Nuclear Decommissioning and related subjects as part of Electrical and Mechanical degree courses. In addition to our relationship with the United Kingdom Atomic Energy Authority (UKAEA) the Dounreay site licensee, we have links with Rolls-Royce and the Ministry of Defence who also share the Dounreay site and with other stakeholders such as, the UK regulator (HSE/NII), the Scottish Environmental Protection Agency (SEPA), local and international contractors and we liaise with the newly formed Nuclear Decommissioning Authority (NDA), who provide some sponsorship and support. We possess our own equipment and laboratories for taking and analysing soil samples and for conducting environmental surveys. Recently we commissioned an aerial survey of contamination in the locality from natural sources, other background levels such as Chernobyl fall out and any local activity from Dounreay.

At present, Chernobyl NPP is under decommissioning after the final shutdown of Unit 3 at the end of 2000. The decommissioning activity is being carried out on the basis of the “Decommissioning Conception for ChNPP” approved in 1992. In accordance with the acting legislation, this concept should be reconsidered in 2002 at the latest. Presently, a new version of the concept is being developed. This document is based on the decommissioning strategy, which foresees the long-term safe storage of reactors’ cores (up to 100 years) and coolant circuit facilities (up to 50 years) within the existing building constructions together with dismantling of auxiliary equipment. Key decisions are the following: 1) the final goal of decommissioning is the condition described as a “brown field site”; 2) decommissioning involves measures for decontamination and dismantling of the contaminated structures; 3) structures having contamination levels at or below free release are considered as “conditionally clear” and for them the decommissioning goals have been achieved; 4) it is anticipated that the dismantling of building constructions and refinement of site will be considered in the framework of Chernobyl Exclusion Zone rehabilitation. This paper describes the decommissioning process for materials and reactor facilities and presents an overview of the decommissioning program activities.

In the framework of the preparation for the decommissioning of the Chernobyl Nuclear Power Plant (ChNPP) an Industrial Complex for Solid Radwaste Management (ICSRM) is going to be built under the EC TACIS Program in the vicinity of ChNPP, comprising: • a solid waste retrieval facility (LOT 1), • a solid waste processing plant (LOT 2), and • a repository for the disposal of short-lived waste (LOT 3).

Behaviour of silicate compositions containing irradiated nuclear fuel, so-called lava-like fuel-containing materials (LFCM), which had been formed as a product of heavy nuclear accident on Chernobyl NPP 4-th Unit in 1986, have been under both the theoretical and workbench investigation. Recent experimental studies indicate, that LFCM and irradiated fuel surface does produce a submicronic radioactive dust spontaneously, i.e. without any external action. The non-contradicting quantitative explanation of observed phenomenon (giant sputtering yield) can be provided when taking into account an electron sputtering mechanism associated with Coulomb explosions, which occur intensively both just beneath a surface of materials under study and inside its volume as well. The last circumstance leads to necessity to reexamine the level of radiation damages in solids containing a large volume concentration of alpha- and beta-emitters in both. In principle, the observed phenomena must be of universal character for all high-radioactive dielectrics, but quantitative characteristics prognosis of its steadiness does depend on initial structure and properties of material. As for LFCM, it has been estimated by computer modeling based on a method of molecular dynamics (MD). The main outcome is the glass matrix cannot serve as a reliable material appointed for alpha radwaste immobilization. A submicronic radioactive dust have been already identified in the destroyed 4-th Unit premises in a large quantities; its regular pollutions in environment represents not a local, but the global problem due to a very special features concerning submicronic dust dissemination in environment.

The problems considered for the substantiation and implementation of a complex rehabilitation territory of the exclusion zone and the zone of absolute resettlement (EZZAR) are directed towards the recovery of its normal economic operation. This process of implementation uses a system of countermeasures. The issues of discussion are normative-legal base, principles, criterion, methods and scenarios of rehabilitation, concept of a full and partial rehabilitation, direction of rehab activity (both without change of the territory status and directed towards the rerun of territories under jurisdiction of local government bodies) and re-evacuation of the population and maintenance of normal conditions of its residents and habitability. State of the art natural and technogenic objects on the territory of EZZAR are discussed concerning preliminary estimations for a capability of practical implementation of different directions of rehabilitation activity on the EZZAR territory. GIS technologies are used to take into account the dynamics of a radioecological situation in natural and semi-natural ecosystems. The chief types of practical activities considered are activities on environmental protection and maintenance in a normal condition of phyto- and zoo-sanitary situation (including forestry activity, activation of landscape-recovery processes, etc.).