Grace Time

Lead Research Organisation: Imperial College London
Department Name: Dept of Mechanical Engineering

Abstract

Following some fault in a nuclear plant, a safe outcome will nonetheless be achieved so long as adequate cooling can be provided to the plant for a period after the fault, and heat generation has naturally fallen to trivial levels. Some faults may themselves have been associated with external events, such as an earthquake or a tsunami, which might have caused external power supplies to the plant to cease to be available. It is thus plainly desirable for the cooling needed by the plant to be provided by holy "passive" means, not dependent on the availability of either site-generated or externally-generated electricity to drive pumps and so on. Providing cooling by passive means such as natural convection is very attractive and very reliable, but it is not an easy phenomenon to predict reliably; for example, just 'how much' cooling will natural circulation provide?. The main objectives of this piece of research are to develop and validate methods to contribute to reliable prediction of this passive cooling.

Planned Impact

Designers and safety assessors of nuclear plant will benefit as this research will increase our ability to make reliable predictions of passive, post-accident cooling of nuclear power plants. Soundly based licensing judgements will both help avoid inadequately safe plants being licensed, and help avoid the refusal to license plants that are actually safe enough, and thus avoid wasteful additional safety systems and studies.

This should facilitate the design of nuclear plants able better to exploit natural circulation flows and passive cooling. It is to be expected that such plants will be both safer, and cheaper to build cheaper to build than conventional plant that uses engineered, powered intervention to effect such cooling.

Nuclear plants that are safer and cheaper will naturally have great economic and societal benefits, ultimately being reflected in electricity prices and reduced fossil fuel burning.

Licensing assessments of new plant are in hand, and likely to be so for the foreseeable future. These improved methods will be able to be used on a timescale of the grant duration, and thus can be used for this licensing.

Engineers and designers working in areas of industry other than nuclear power, but where natural circulation and buoyancy driven flows are important, will benefit also from the availability of more reliable prediction methods.

People and skills: The project will lead to the development of highly skilled researchers in the general area of nuclear thermal hydraulics. This area of skills has declined greatly in the last few decades in United Kingdom. It is an area also which is enormously in demand to support the United Kingdom government's intended new-built programme for nuclear power stations. Any increase in capability here is to be welcomed.

Publications

10 25 50
 
Description Grant no. EP/M018733/1 is within the Indo-UK programme, examining the period of 'Grace time' facilitated by passive cooling via natural circulation following reactor faults.

Core activities in the project include collaboration between Imperial and BARC, with the BARC team building a natural circulation flow facility on which they are to make measurements for validation of CFD models developed at Imperial.

The 'Imperial' part of the project involves:
- development of methods for fundamental, CFD-based modelling of a range of buoyancy driven flows, via comparison with and validation against measurements;
- application of the above CFD-based methods to modelling fault scenarios following suppression of natural circulation flows due to accidental cooling of part of these loops.

In addition, these activities are linked to a simultaneous PhD project in the Nuclear Group at Imperial.

The 'India' part of the project involves BARC building and instrumenting a buoyant-flow test rig. The rig has been designed at Imperial using CFD modelling. The rig has now been successfully built and commissioned at BARC. Measurements for laminar flow have been made and comprehensive sets of measurements have been supplied to the Imperial College team. These data have now been used for the validation work of the CFD in that specific flow regime and the results of the comparisons are very promising.
Exploitation Route In due course we expect these methods will be able to be used by those performing analyses of nuclear power plants, demonstrating their ability to be cooled by natural circulation methods.
Sectors Energy

 
Description Collaboration with Indian DAE BARC 
Organisation Bhabbha Atomic Research Centre
Country India 
Sector Public 
PI Contribution We are collaborating in a series of projects under the Indo-UK Civil Nuclear Programme
Collaborator Contribution We and BARC work together on developing measurements associated with various aspects of nuclear thermal hydraulics, and in the development and validation of models of these phenomena
Impact Multiple publications, multiple visits to BARC, multiple hostings of Indian scientists in the UK
Start Year 2015
 
Description Collaboration with PhD project in the Nuclear Engineering Group, Mechanical Engineering Department, Imperial College. 
Organisation Imperial College London
Country United Kingdom 
Sector Academic/University 
PI Contribution Some of the research tasks of this project have been linked to a PhD project started in 2017 in the Nuclear Engineering Group, Mechanical Engineering Department, Imperial College. Both the Grace Time grant PI and one of the grant investigators have been involved in the initiation and supervision of the research work undertaken by a PhD student working on Computational Fluid Dynamics modelling of natural circulation flows in loops.
Collaborator Contribution The PhD student validated and tested Computational Fluid Dynamics simulation methodologies that are simultaneously being used for conducting the Grace Time grant research.
Impact Too early to say, the collaboration and award are still active.
Start Year 2017
 
Description ERCOFTAC workshop 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Study participants or study members
Results and Impact Workshop using the results generated by our study of natural circulation at its basis.
Year(s) Of Engagement Activity 2019
URL https://www.ercoftac.org/
 
Description Indo-UK Civil Nuclear Network Conference & Meeting. 30 - 31 October 2019 Halifax Hall, Sheffield University. 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Study participants or study members
Results and Impact Indo-UK Civil Nuclear Network Conference & Meeting. 30 - 31 October 2019 Halifax Hall, Sheffield University. Annual gathering of researchers working on collaborative Indo-UK civil nuclear research projects. Talks and presentations on work done under Indo-UK collaborative grants.
Year(s) Of Engagement Activity 2019
 
Description Indo-UK Civil Nuclear Network Meeting. 03 July 2017 Mechanical Engineering Department, Imperial College London. 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Study participants or study members
Results and Impact ndo-UK Civil Nuclear Network Meeting. 03 July 2017 Mechanical Engineering Department, Imperial College London. Annual gathering of researchers working on collaborative Indo-UK civil nuclear research projects. Talks and presentations on work done under Indo-UK collaborative grants.
Year(s) Of Engagement Activity 2017
 
Description Indo-UK Civil Nuclear Network Meeting. 19 - 20 December 2016 Halifax Hall, Sheffield University. 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Study participants or study members
Results and Impact Indo-UK Civil Nuclear Network Meeting 19 - 20 December 2016 Halifax Hall, Sheffield University. Annual gathering of researchers working on collaborative Indo-UK civil nuclear research projects. Talks and presentations on work done under Indo-UK collaborative grants.
Year(s) Of Engagement Activity 2016
 
Description Indo-UK Civil Nuclear Network Meeting. 20 September 2018 The Open University, Milton Keynes. 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Study participants or study members
Results and Impact Indo-UK Civil Nuclear Network Meeting. 20 September 2018 The Open University, Milton Keynes. Annual gathering of researchers working on collaborative Indo-UK civil nuclear research projects. Talks and presentations on work done under Indo-UK collaborative grants.
Year(s) Of Engagement Activity 2018
 
Description Online resources: official website of the Indo-UK Civil Nuclear Network, https://indouk-civilnuclear.org 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Generation of online resources available to everyone is interested at https://indouk-civilnuclear.org. Information on current and previous Indo-UK grants; publications; events; past and upcoming workshops and meetings.
Year(s) Of Engagement Activity 2018,2019,2020
URL https://indouk-civilnuclear.org
 
Description Talk by Arun Srivastrava, International Secretary, Indian Department of Atomic Energy on "The Indian atomic energy programme; an overview". Indo-UK Civil Nuclear Network Meeting 19 - 20 December 2016 Halifax Hall, Sheffield University 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Study participants or study members
Results and Impact The Indian DAE delegate Arun Srivastava gave a presentation on the Indian atomic energy programme to UK researchers working on collaborative Indo-UK civil nuclear grants. The talk was part of the 2016 Indo-UK Civil Nuclear Network Meeting.
Year(s) Of Engagement Activity 2016
 
Description UKFN SIG in Nuclear Thermal hydraulics 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact Meeting of the UKFN SIG in Nuclear Thermal Hydraulics was organziedat the University of Leeds and included specific talks on ongoing EPSRC funded research. The audience included around 50 delegates from other Uk universities, industry and the office for nuclear regulation
Year(s) Of Engagement Activity 2019