New Construction of an In-Drum Drying Plant in the Central Decontamination and Water Treatment Facility (ZDW)

Author(s):  
Martin Hoffmann ◽  
Ingmar Koischwitz ◽  
Jörg Viermann

During the operation and dismantling of nuclear plants, a variety of radioactive liquid wastes accumulate, which must be supplied to a disposal chain suitable for final disposal. In the initial conditioning step, with regard to their chemical properties these waste waters are usually adjusted by water treatment systems (predominantly evaporation facilities) permanently installed in nuclear power plants, and then, they are concentrated up to a predefined content of solids. Afterwards, the developing evaporator concentrate is desiccated locally and suitable for final disposal by own permanently installed conditioning installations or by means of mobile plants. For a mobile conditioning of evaporator concentrates, GNS uses the drying plant of the type FAVORIT proven over decades. Each of the mobile FAVORIT processing plants is provided with a handling licence for Germany valid nationwide according to § 7 of the German Radiation Protection Ordinance (StrlSchV).

2020 ◽  
Vol 20 (2) ◽  
pp. 127-132
Author(s):  
Namjin Cho ◽  
Dongsu Im ◽  
Jungdon Kwon ◽  
Teayeon Cho ◽  
Junglim Lee

Nuclear power plants store and use flammable gases and liquids and consequently risk explosions. Therefore, nuclear plants employ explosion-proof equipment; however, this equipment is not always sufficiently maintained. This lack of maintenance can affect the safety-related equipment intended to shut down the reactor, because the explosion-proof equipment itself can act as an ignition source. Radio-frequency identification (RFID) technology should be explored as a tool to improve both the convenience and efficiency of maintenance. We analyzed and compared explosion-proof RFID technology that can be used in nuclear power plants.


Author(s):  
J. Douglas Hill ◽  
Paul Moore

Nuclear power plants rely on Instrumentation and Control (I&C) systems for control, monitoring and protection of the plant. The original, analog designs used in most nuclear plants have become or soon will be obsolete, forcing plants to turn to digital technology. Many factors affect the design of replacement equipment, including long-term and short-term economics, regulatory issues, and the way the plant operates on a day-to-day basis. The first step to all modernization projects should involve strategic planning, to ensure that the overall long and short-term goals of the plant are met. Strategic planning starts with a thorough evaluation of the existing plant control systems, the available options, and the benefits and consequences of these options.


Author(s):  
Alberto Del Rosso ◽  
Jean-François Roy ◽  
Frank Rahn ◽  
Alejandro Capara

This paper presents a general approach to evaluate the risk of trip or Loss of Off-site Power (LOOP) events in nuclear power plants due to contingencies in the power grid. The proposed methodology is based on the Zone of Vulnerability concept for nuclear plants introduced by EPRI in previous work. The proposed methodology is intended to be part of an integrated probabilistic risk assessment tool that is being developed under ongoing EPRI R&D programs. A detailed analysis of many events occurred in actual nuclear plants has been performed in order to identify, classify and characterize the various vulnerability and type of failures that may affect a nuclear plant. Based the outcome of that analysis, a methodology for evaluating the impact of off-site transmission system events on nuclear plants has been outlined. It includes description of the type of contingencies and conditions that need to be included in the analysis, as well as provisions regarding the simulation tools and models that should be used in each case. The methodology is illustrated in a simplified representation of the Western Electricity Coordinating Council (WECC) system in the U.S.


Author(s):  
Robert K. Perdue ◽  
G. Gary Elder ◽  
Gregory Gerzen

Certain nuclear power plants have “Rev B” reactor vessel upper internals guide tube support pins, commonly referred to as split pins, made from material with properties similar to Alloy 600 and known to be susceptible to primary water stress corrosion cracking (PWSCC). This paper describes a rigorous probabilistic methodology for evaluating the economics of a preemptive replacement of these split pins, and describes an application at four of Exelon Generation’s nuclear plants. The method uses Bayesian statistical reliability modeling to estimate a Weibull time-to-failure prediction model using limited historical failures, and a Westinghouse proactive aging management simulation tool called PAM to select a split pin replacement date that would maximize the net present value of cash flow to a plant. Also in this study is a sensitivity evaluation of the impact of zinc addition on split pin replacement timing. Plant decisions made based in part on results derived from applying this approach are noted.


Author(s):  
Asko Vuorinen

The Finnish companies have built four medium size nuclear power plants. In addition they have constructed two nuclear icebreakers and several floating power plants. The latest 1650 MWe nuclear power plant under construction Olkiluoto-3 has had many problems, which have raised the costs of the plant to €3500/kWe from its original estimate of €2000/kWe and constriction schedule from four to eight years. It is possible to keep the costs down and schedule short by making the plant in shipyard and transport it to site by sea. The plant could be then lifted to its place by pumping seawater into the channel. This kind of concept was developed by the author in 1991, when he was making his thesis of modular gas fired power plants in Helsinki University of Technology. The modular construction of nuclear plants has made in a form of two nuclear icebreakers, which Wa¨rtsila¨ Marine has built in Helsinki Shipyard. The latest modular nuclear plant was launched in 2010 in St Petersburg shipyard. One of the benefits of modular construction is a possibility to locate the plant under rock by making the transportation channels in tunnels. This will give the plant external protection for aircraft crash and make the outer containment unnecessary. The water channels could also be used as pressure suppression pools in case of venting steam from the containment. This could reduce the radioactive releases in case of possible reactor accidents. The two 440 MW VVER plants build in Finland had construction costs of €1600 /kWe at 2011 money. The author believes that a 1200 MW nuclear plant with four 300 MW units can be constructed in five years and with €3300/kW costs, where the first plant could be generating power within 40 months and next units with 6 month intervals.


Membranes ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 98
Author(s):  
Jaromír Marek

The article first summarizes case studies on the three basic types of treated water used in power plants and heating stations. Its main focus is Czechia as the representative of Eastern European countries. Water as the working medium in the power industry presents the three most common cycles—the first is make-up water for boilers, the second is cooling water and the third is represented by a specific type of water (e.g., liquid waste mixtures, primary and secondary circuits in nuclear power plants, turbine condensate, etc.). The water treatment technologies can be summarized into four main groups—(1) filtration (coagulation) and dosing chemicals, (2) ion exchange technology, (3) membrane processes and (4) a combination of the last two. The article shows the ideal industry-proven technology for each water cycle. Case studies revealed the economic, technical and environmental advantages/disadvantages of each technology. The percentage of technologies operated in energetics in Eastern Europe is briefly described. Although the work is conceived as an overview of water treatment in real operation, its novelty lies in a technological model of the treatment of turbine condensate, recycling of the cooling tower blowdown plus other liquid waste mixtures, and the rejection of colloidal substances from the secondary circuit in nuclear power plants. This is followed by an evaluation of the potential novel technologies and novel materials.


Author(s):  
D. G. Lee ◽  
Y. J. Cho ◽  
H. C. Yang ◽  
K. W. Lee ◽  
C. H. Jung

Graphite has been used as a moderator and reflector of neutrons in more than 100 nuclear power plants as well as many experimental reactors and plutonium production reactors in various countries. Most of the older graphite moderated reactors are already shut down and are awaiting decommissioning planning and preparation. The graphite waste has different characteristics than other decommissioning waste due to its physical and chemical properties and also because of the presence of tritium and carbon-14. Therefore radioactive graphite dismantling, handling, conditioning and disposal are a common part of the decommissioning activities. A volume reduction of the waste is needed to reduce disposal cost of radioactive waste. However the existing processing technologies are based mostly on the isolation of radioactive graphite from the environment, they are not able to provide for a significant volume reduction. For this reason, the high-temperature thermal treatment process such as an incineration or a pyrolysis is considered as promising technologies, since it provides a substantial volume reduction. Currently, the fluidized bed incineration is considered as efficient technology for the treatment of radioactive graphite waste. In this study, the fluidized bed incineration condition and the radioisotopes behavior were experimentally investigated by using irradiated graphite waste which has arisen from the decommissioning of Korean Research Reactor 2 (KRR-2).


2002 ◽  
Vol 13 (2) ◽  
pp. 239-261
Author(s):  
Steve Thomas

In 1990, the privatisation of the British electricity supply industry revealed how uneconomic Britain's nuclear power plants were. The nuclear sector was withdrawn from privatisation and it seemed likely that by 2000, most of Britain's nuclear power plants would be closed. However, operating costs were dramatically reduced and in 1996, most of the nuclear plants were privatised in British Energy. Nuclear output made an important contribution to the reduction of greenhouse gas emissions and the future looked secure for the existing plants. However, the early success of British Energy was based on an inflated wholesale electricity price and by 2000, British Energy was struggling to cover its costs. The British government is now conducting a review of energy policy. The economic case for new nuclear power plants is poor but the need to meet greenhouse gas emission targets and the influence British Energy and BNFL may ensure the long-term future of the existing plants.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Akponanabofa Henry Oti ◽  
Peter Farrell ◽  
Fonbeyin Henry Abanda ◽  
Paul McMahon ◽  
Abdul-Majeed Mahamadu ◽  
...  

Purpose The relatively low capital cost and contributions to mitigating global warming have favoured the continuous construction and operation of nuclear power plants (NPPs) across the world. One critical phase in the operation of nuclear plants for ensuring the safety and security of radioactive products and by-products is decommissioning. With the advent of digital twinning in the building information modelling (BIM) methodology, efficiency and safety can be improved from context-focus access to regulations pertaining to demolition of structures and the cleaning-up of radioactivity inherent in nuclear stations. The purpose of this study, therefore, is to propose a BIM-driven framework to achieve a more regulation-aware and safer decommissioning of nuclear power plants. Design/methodology/approach The framework considers task requirements, and landscape and environmental factors in modelling demolition scenarios that characterise decommissioning processes. The framework integrates decommissioning rules/regulations in a BIM linked non-structured query system to model items and decommissioning tasks, which are implemented based on context-focussed retrieval of decommissioning rules and regulations. The concept’s efficacy is demonstrated using example cases of digitalised NPPs. Findings This approach contributes to enhancing improvements in nuclear plant decommissioning with potential for appropriate activity sequencing, risk reduction and ensuring safety. Originality/value A BIM-driven framework hinged on querying non-structured databases to provide context-focussed access to nuclear rules and regulations and to aiding decommissioning is new.


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