atw - March 2017

Analysis of Filtered Contaiment Venting
Load Flexibility of Nuclear Power Plants with ALFC
Disposal for High Radioactive Waste
Brexit and EURATOM

Lack of Reliable Alternatives Means France Faces Challenges Finding a Replacement for Nuclear


The lack of alternative low-carbon energy sources that are as reliable as nuclear means France’s “ambitious” plans to reduce its share of nuclear from 78 % in 2015 to 50 % by 2025 might not be achievable, the International Energy Agency (IEA) said in its January 2017 report. The Paris-based agency said France – which has the world’s highest share of nuclear in its electricity mix – must assess possible changes in energy demand and supply and to guarantee “continuous security of electricity supply” as it pushes ahead with its plans for an “energy transition” up to 2050. The Energy Transition for Green Growth Act (Loi relative à la transition énergétique pour la croissance verte, LTECV) was the result of consultations that ran from January to July 2013.

What People Really Think about Nuclear Energy


Nuclear power is a reliable, baseload, low-carbon energy source that can contribute to the fight against climate change. It is also competitive and can help reduce energy dependency. It is vital that politicians take the lead and implement bold decisions regarding the energy mix. Developments in Finland and the UK show that if the political decision to include nuclear in the energy mix is taken and information is communicated in an open, inclusive and democratic way, people tend to become more favourable to nuclear power. The March 2011 accident at the Fukushima-Daiichi nuclear plant in Japan had an impact on public opinion towards nuclear power. Yet the results of opinion polls carried out throughout Europe after the accident show that opinion is polarised and country specific.

Environmental Impact Assessment Modern Dressed? To the Amendment of the EIA Act and other Acts and Regulations

Ulrike Feldmann

On 22 December 2016, the Federal Ministry for the Environment (BMUB) presented the “Draft Act for the Modernization of the Act on the Environmental Impact Assessment” within the framework of the association consultation, as well as the “Draft first Ordinance Amending the Ordinance on the Approval Procedure – 9. BImSchV”. The EIA Modernization Act as well as the Atomic Act Procedure Regulation and the Federal Mining Act should be revised by terms of an omnibus act. The association consultation was held on 18 January 2017.

Analysis of Design and Operational Effects of Filtered Containment Venting on Depressurization and Fission Product Release

Jong Woon Park, Wook-Cheol Seol and Jisu Kim

Effects of design and operational parameters of filtered containment venting system during a specified containment depressurization and relative aerosol release amount are analyzed. The analyses is performed by using the MAAP4 code for the APR1400 reactor. Major results uniquely identified from the analyses can be noted as following: Even though containment depressurization is accelerated as the pipe size increases, the venting system solution is also depleted earlier. Elapsed times to reach lower end pressure of 2 bar are nearly identical regardless of the vent initiation pressure and thus early venting is not much beneficial than late venting. Stroke time of the isolation valves has no effect on the depressurization performance and thus slow opening is beneficial for load reduction from the vent effluent.

Real-time Management by Cloud Computing System Dynamics for Risk Analysis of Fukushima Nuclear Power Plant Accident

Hyo Sung Cho and Tae Ho Woo

The earthquake and tsunami induced accident of nuclear power plant (NPP) in Fukushima disaster is investigated by the real-time management (RTM) method. This non-linear logic of the safety management is applied to enhance the methodological confidence in the NPP reliability. The case study of the earthquake is modeled for the fast reaction characteristics of the RTM. The system dynamics (SD) modeling simulations and cloud computing are applied for the RTM method where the real time simulation has the fast and effective communication for the accident remediation and prevention. Current tablet computing system can improve the safety standard of the NPP. Finally, the procedure of the cloud computing system dynamics (CCSD) modeling is constructed.

Improving Automated Load Flexibility of Nuclear Power Plants with ALFC

Andreas Kuhn and Peter Klaus

In several German and Swiss Nuclear Power Plants with Pressurized Water Reactor (PWR) the control of the reactor power was and will be improved in order to be able to support the energy transition with increasing volatile renewable energy in the grid by flexible load operation according to the need of the load dispatcher (power system stability). Especially regarding the mentioned German NPPs with a nominal electric power of approx. 1500 MW, the general objectives are several automated grid relevant operation modes. The new possibilities of digital I&C (as TELEPERM® XS) enable the automation of this operating modes provided that manual support is no longer necessary. These possibilities were and will be implemented by AREVA within the ALFC-projects. Manifold adaption algorithms to the reactor physical variations during the nuclear load cycle enable a precise control of the axial power density distribution and of the reactivity management in the reactor core. Finally this is the basis for a highly automated load flexibility with the parallel respect and surveillance of the operational limits of a PWR.

Application of CATE 2.0 Code on Evaluating Activated Corrosion Products in a PWR Cooling Loop

Jingyu Zhang, Lu Li and Yixue Chen

In PWR plants, most Occupational Radiation Exposure (ORE) for personnel results from Activated Corrosion Products (ACPs) in the cooling loop. In order to evaluate the ACPs in the cooling loop, a three-region transport model is built up based on the theory of driving force from the concentration difference in CATE 2.0 code. In order to analyze the nuclide composition of ACPs, the EAF-2007 nuclear database is embedded in CATE 2.0. The case of MIT PCCL test loop is simulated to test the availability of CATE 2.0 on PWR ACPs evaluation, and the activity of Co-58 and Co-60 after operation for 42 days calculated by CATE 2.0 is consistent with that from the code CRUDSIM adopted by MIT. Then, the nuclide composition of ACPs is analyzed in detail respectively for operation of 42 days and 12 months using CATE 2.0. The results show that the short-lived nuclides contribute a majority of the activity in the regions of in-flux wall and coolant, while the long-lived nuclides contribute most of the activity in the region of out-flux wall.

The Long Path to a Disposal for High Radioactive Waste – A New Approach for a Better Understanding of Processes and the System in a Whole – Part I

Karl-Heinz Lux, Ralf Wolters and Juan Zhao

A new conceptual-configurative approach and a new simulation tool for the development of an improved process and system understanding for HAW disposal systems – without and with direct long-term monitoring are presented and discussed. With regard to the final repository development, a retrievability of the heat-generating high-radioactive waste during the storage phase and a general recoverability during the first 500 years after closure of the repository in the post-closure phase are required. Both for the monitoring of the repository during the storage phase as well as thereafter, a direct monitoring of the storage horizon could be implemented as an alternative to an indirect monitoring.

Non-Conformal Contact Mechanical Characteristic Analysis on Spherical Components Corrosion Products in a PWR Cooling Loop

G. Zhen-zhi, H. Bin, G. Zhen-ming, Y. Feng-mei and Q. Jin

Non-conformal spherical-contact mechanical problems is a three-dimensional coordination or similar to the coordination spherical contact. Due to the complexity of the problem of spherical-contact and difficulties of solving higher-order partial differential equations, problems of three-dimensional coordination or similar to the coordination spherical-contact is still no exact analytical method for solving. It is based on three-dimensional taper model is proposed a model based on the contour surface of the spherical contact and concluded of the formula of the contact pressure and constructed of finite element model by contact pressure distribution under the non-conformal spherical. The results shows spherical contact model can reflect non-conformal spherical-contacting mechanical problems more than taper-contacting model, and apply for the actual project.

What Future for Euratom as the UK Prepares for its ‘Nuclear Independence’?

John Shepherd

UK government ministers have been keeping European leaders guessing over what their negotiating position will be when formal talks start about the ‘divorce’ from the European Union. However, for the nuclear energy community, there was one very certain statement in recent weeks about what Brexit will also mean: withdrawal from the Euratom Treaty.


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