The Advantages of Molten Salt l R d hNuclear Reactors and the

Results of a GovernmentResults of a Government Sponsored Feasibility Study

Trevor R Griffiths: Energy Process Developments LtdVladimir A Volkovich: Ural Federal UniversityVladimir A Volkovich: Ural Federal University,

Ekaterinberg, RussiaBarry Snelson MBE: Former MD, Sellafieldy

Oak Ridge National LaboratoryX10 siteX10 site

Oak Ridge National Laboratory Commemorative MedalElectroplated with Gold with Electricity from their

Fi t I d t i l R tFirst Industrial Reactor

ORNLORNL

Elaborate models were set up for engineering studies on a new reactor concept.

Oak Ridge scientists gworking on the mock-up of a reactor in pwhich the fuel is molten uranium salts

Reactors for Power Plants but which to build?

80 reactor designs originally considered by the US Atomic Energy Commission

Five different types for construction and operation Same five types in use today for Gen IV assessment ORNL considered that the molten salt reactor concept

offers many potential economic advantages over other reactor designs, later emphasised its safety features

Fuel in solution so no fabrication of fuel elements necessary and continuous removal of fission products possible

ORNL Molten Salt Reactor Strong support from Eugene Wigner (Nobel Lauriat)

and Alvin Weinberg (ORNL Director) for a chemistryand Alvin Weinberg (ORNL Director) for a chemistry-based reactor with fuel in a molten salt

They considered that a molten salt breeder reactor had They considered that a molten salt breeder reactor had the greatest promise for a future need for man: cheap and abundant energyand abundant energy

Their MSRE, Molten Salt Reactor Experiment, was built and achieved all asked or expected of itbuilt and achieved all asked or expected of it.

What became of it?

Why do we not have it today?y y Admiral Rickhover pushed for a water-cooled reactor to

power the nuclear submarine Nautilus (Weinberg p ( gremarked that Rickhover was not at the top of the class at the ORNL School for Nuclear Technology!)Ri kh f d hi d i f i il h Rickhover favoured this design for civil energy, hence many PWR/BWRs (when the Canadian CANDU was better) were hastily adopted and sold internationally) y p y

The US space programme was now taking money from nuclear energy R and D programmes

Molten salt reactors do not produce the plutonium that the US military and Government then wanted so funding for nuclear was reduced and finally withdrawnnuclear was reduced and finally withdrawn

Why are Molten Salt Reactors safe?y Cannot undergo meltdown, already in molten state Cannot explode (no water involved Fukushima) Cannot explode (no water involved, Fukushima) No large pressure vessels needed – atmospheric

pressurepressure Should they overheat then a bottom plug of solid salt

melts and the melt drains into a large drain-tank and gthus fission stops

No plutonium produced, can use plutonium as fuel Fuel and fission products can be treated continuously

onsite

Situation today - Developments A molten salt reactor MSR is a Gen IV option A molten salt reactor, MSR, is a Gen IV option ORNL published all their reports so others could

rebuilt (and develop further)rebuilt (and develop further) Related technological improvements being

investigatedinvestigated Several groups worldwide are currently considering

MSRs and their advantagesMSRs and their advantages Now is the time to seek the best design (for UK)

E P D l h f TSB Energy Process Developments has a grant from TSB, Technology Strategy Board, now Innovate UK, of £100 000 to carry out a feasibility study£100,000 to carry out a feasibility study

Press Release:Press Release:Nuclear E i i

Funds have been awarded by the UK’s innovation agency, the Technology Strategy Board, for a feasibility study for the installation of a UK pilot scale Molten SaltEngineering

International

installation of a UK pilot scale Molten Salt Reactor.Jasper Tomlinson tells us 'Currently we are strengthening our project team and looking for appropriate specialists with

11 June 2014looking for appropriate specialists with commitment to a project of this nature'.

Tremendous knowledge growth in the 60 years of the first nuclear era has not seen substantial d i l fi i t h l b dadvances in nuclear fission technology beyond

the PWR, initially a hastily adopted device for military and civil applications, and essentially comprising water cooling of solid fuel l Th i i d lelements. The imminent second nuclear era

requires introduction of inherently more efficient, safer, cheaper, nuclear fission power obtainable with liquid fuelled – namely Molten S l R (MSR) h l h b fSalt Reactor (MSR) - technology the best out of the six Gen IV options, but not currently the option nearest implementation.

A very first step can be seen as the installationA very first step can be seen as the installation and operation of a pilot scale demonstration MSR.

Principal Agenda Items( ) U G t f di f f ibilit f tti (1) Use Government funding for feasibility of setting up and operating a UK pilot scale demonstration MSR. Such reactors technically feasible with present engineering

bili i Thi d i hcapabilities. This does not require research or new knowledge. If our study shows not feasible in the UK likely to be because of the regulatory constraints in terms of

d d l ll l lexpense and delay - essentially political issues. (2) Work programme is to validate forthcoming proposals.

Then each is assessed, comparing their suitability in theThen each is assessed, comparing their suitability in the UK for informing the public, media and decision-makers of the characteristics of liquid-fuelled fission reactors plus creating a platform for development work on componentscreating a platform for development work on components, etc., and a possible role in training engineers and operators.

(3) Writing the terms of reference for a full engineering (3) Writing the terms of reference for a full engineering design for the appropriate option, assuming such a UK reactor project is found to be feasible. This design activity

ld d f th f di f th k i l d dwould need further funding for the work involved and involvement by partners not yet identified.

How did we use the grant?g TSB grant started in October 2014, ended in June 2015

A k d h ( illi ) MSR h l i h Asked the (willing) MSR technology community what they would do if they had the funds to construct and operate a UK pilot scale demonstration MSRoperate a UK pilot scale demonstration MSR

Hence we examined technology currently thought useable and ready and aimed to put these proposals onuseable and ready and aimed to put these proposals on a level playing field

C th k f th f di f t f ll Can then seek further funding for a separate full design study for the chosen option

l S l d id iMolten Salt Reactors under consideration In January a team from Energy Process Developments

h d di i d h d hhad discussions around the UK and went out to the States and Canada to visit ORNL and other institutions to talk about their plans and designsto talk about their plans and designs

Places and groups visited included: Moltex Simple Salt Reactor (SSR) (UK based) Moltex – Simple Salt Reactor (SSR) (UK-based) Seaborg Technologies – Seaborg Waste Burner (SWaB) Flibe Energy Liquid Fluoride Thorium Reactor Flibe Energy – Liquid Fluoride Thorium Reactor

(LFTR) Martingale Inc (ThorCon)Martingale Inc. (ThorCon) Terrestrial Energy (IMSR) Transatomic Power Reactor (TAP) Transatomic Power Reactor (TAP)

Existing MSR Proposals (a)g p ( ) Renewed interest in the MSR concept in Japan, Russia,

China, France and the USAChina, France and the USA CNRS at Grenoble has a long term development

programme led by Elsa Merle-Lucotte for a fast p g yspectrum MSR

FLIBE Energy, founded by Kirk Sorensen in Canada, has a 40MW thermal reactor design with lithium fluoride/beryllium fluoride as coolantF ji MSR i MW b d d i Fuji MSR is a 100-200 MWe near-breeder design promoted by a Japanese, Russian and US consortium (ITHMISI) founded by the late Dr Kazuo Fukukawa(ITHMISI) founded by the late Dr Kazuo Fukukawa

Existing MSR Proposals (b)g p ( ) Lithium Fluoride Thorium Reactor (LFTR) is a

heterogeneous MSR design that breeds its U-233 fuel from f l bl k f l h b ll l ha fertile blanket of lithium-beryllium salts that contains

thorium fluoride Moltex Energy LLP exploits Ian Scott’s innovative SimpleMoltex Energy LLP exploits Ian Scott s innovative Simple

MSR fast spectrum pool type design Thorenco has a design for a pilot scale pool type LFTR

T i l E f C d bli h d d l Terrestrial Energy of Canada was established to develop the Denatured Molten Salt Reactor (DMSR) by exploiting David Le Blanc’s intellectual property rights

Transatomic Power proposes a fleet of 200MWe waste annihilating molten salt reactors (WAMSR) to consume the world’s existing 270,00 tonnes of spent nuclear fuel rodsworld s existing 270,00 tonnes of spent nuclear fuel rods

Q ti f l i tQuestions from nuclear inspectors Technology: Materials of Construction, Fuel & Salt, gy , ,

Reprocessing Method Safety & Environment: Is it Fully Passively Safe? Quantity &

S i f A id P ibl Abili T SSeverity of Accidents Possible, Ability to Treat Spent Nuclear Fuel, Is it Sustainable?

Security: Proliferation Resistance Ability/Need to Security: Proliferation Resistance, Ability/Need to Reprocess, Sabotage Resistance

Simplicity: Ease of Construction, Construction and Design p y gProgram, Availability of Materials & Components

Licensability: Fuel & Salt, Waste Processing & Disposal, R t O tiReactor Operation ,

Reactor Characteristics : Practicality of O&M, Suitability as a MSR research facility, Outputs of Reactora MSR research facility, Outputs of Reactor

Fl id tFluoride reactors ORNL Molten Salt Reactor Experiment, MSRE, used p , ,

fluoride salts and thorium and uranium fuel This design has been up-graded/modified into the s des g as bee up g aded/ od ed to t e

LFTR, Liquid Fluoride Thorium Reactor by FLIBE Energy in Canada (Lithium Beryllium Fluoride)gy y

The Moltex Simple MSR is designed in the UK as a fast spectrum pool type reactor, originally conceptualised p p yp g y pat ORNL but will use chlorides instead of fluorides

The Transatomic Power Reactor, TAP, currently on , , ypaper but an interesting design

Liquid Fluoride Thorium ReactorNuclear Engineer Ed Phiel compiled aNuclear Engineer Ed Phiel compiled a

Summary of LFTR advantages1 Low PU-239 production39 p2 Compared with LWR, 1% of radioactive waste volume3 Waste contains virtually no fissile materials, so criticality concerns during

waste handling are eliminatedb b l4 No xenon neutron absorption causing LWR start-up instability

5 Inherently safe by thermal expansion shutting down fission with increasing temperatures

6 Core is already molten so can’t melt down6 Core is already molten so can t melt down7 No risk of coolant flashing to steam sending fission products airborne and

losing cooling (Fukushima)8 Entire core can be automatically dumped to self-critical configuration, with y p g ,

indefinite air cooling decay heat removed if it overheats or for any other reason9 Core is load-following and self-controlling based on temperature changes with

no control rods needed for load changesTh i i il bl l t f f f th i i ti iti t10 Thorium is available almost for free from rare earth mining activities waste streams

11 Thorium is less radioactive than uranium12 LFTR has on-line refuelling so no periodic shutdowns12 LFTR has on line refuelling, so no periodic shutdowns

More reasons 13 LFTR does not need excess reactivity in its core requiring suppression by 13 LFTR does not need excess reactivity in its core requiring suppression by

control rods and in neutron-absorbing poisons 14 LFTR breeds its own fissile fuel and which can be removed from the blanket

b fl i i th h d t t t th t f d t thby fluorine gas purging, then hydrogen gas treatment, then transferred to the core

15 Single fluid proof-of-concept molten salt reactors been built and operated by ORNLORNL

16 Fissile U-233 contains U-232, a decay precursor to thallium emitting a 2.6 MeV gamma radiation, making U-233 unsuitable for military weapons

d iproduction 17 No core infrastructure cost since the core is molten salt, greatly reduces

operational costs versus PWR/BWR 18 LFTR can be 44 – 50% efficient compared to 33% for BWR/BWR 19 LFTR efficiency allows possibility of having purely a-cooled reactors for arid

or cold regionsg 20 Fluoride salt is less corrosive than hot water 21 PWR/BWR zirconium plus water to hydrogen production is eliminated, so

Fukushima-like hydrogen explosions are eliminatedFukushima-like hydrogen explosions are eliminated

And more...22 Fluorine forms ionic salts that are extremely stable in a radiation field, even compared to water23 Fluoride salts boiling point is 400-700 C above the operational23 Fluoride salts boiling point is 400 700 C above the operational temperature, so boiling is not a possibility, the reactor shuts itself down far below those temperatures24 Fission gases are continuously removed and stored safely, so breach of 4 g y y,containment would not release them25 Other fission products can also be removed on-line and safe-stored away from the reactor core26 Thorium fuel is 4x as common as uranium27 Thorium is 560x as common as U-23528 Thorium is found in higher concentrations than uranium due to higher chemical stability29 Much less mining is required compared to LWRs30 LFTR is highly scalable from small plants to large plants

LFTR31 LFTR reactors are very compact32 No CO2 emissions33 LFTR only requires a small containment structure, because there is no steam or h drogen e plosion to containsteam or hydrogen explosion to contain34 Because LFTR is small it can be built underground for further protection

Examples of various designs Moltex - Simple Molten Salt Reactor

Single SSR fuel tubeSingle SSR fuel tube - not to scale

Side view 3D- view

Seaborg TechnologiesSeaborg TechnologiesReactor Scheme Section through core used for simulationsReactor Scheme Section through core used for simulations

Flibe energygyIllustrative view of the core showing

the fissile zone in blue, fertile zone in green and the reflectors in black at the

Schematic of LFTR reprocessing systemgreen and the reflectors in black at the

perimeter

Martingale Inc (Thorcon)Martingale Inc. (Thorcon)

Section through core in plan view showing the graphite logs

Section through reactor vessel showing the core - ‘POT’, pump -

Close up section through h l

g p p‘PLP and heat exchanger - ‘PHX’

graphite log

Terrestrial Energy - Integrated MSRgy g

Section through IMSR core

Transatomic Power Reactor (TAP)Transatomic Power Reactor (TAP)

Illustrative view of TAP reactor island Schematic of TAP reactor

N id d i iNot considered in our assessment exercise

Our Molten Salt Reactor option for Gen IV is the Moltex Simple Salt ReactorGen IV is the Moltex Simple Salt Reactor The Simple MSR is designed in the UK as a fast spectrum pool type

t i i ll t li d t ORNL A f ll i i ireactor, originally conceptualised at ORNL. A full size version is expected to be 1GWe and a prototype circa 150MWth, large enough to reach criticality.

The fuel salt, comprises of 60% NaCl and 40% plutonium, uranium and lanthanide trichlorides and sits in PE16 tubes, a nickel-iron-chromium alloy in use now in nuclear applications (molybdenum as achromium alloy in use now in nuclear applications (molybdenum as a failsafe if experiments fail) at the centre of a pool of coolant salt. The primary fissile fuel is Pu-239 recovered from conventional reactor spent fuel The coolant salt is ZrF4 KF NaF (42 48 10) which transfers thefuel. The coolant salt is ZrF4-KF-NaF (42-48-10) which transfers the heat from the centre of the pool to the heat exchangers at the outside edge by natural convection, assisted by a small impeller. The heat

h ffi i tl f f th f l t b th t texchangers are sufficiently far from the fuel tubes that neutron bombardment is negligible. The neutrons are stopped by a reflector at the outer edge of the fuel tubes and by the coolant salt itself. The fuel

b h l f f b f h d h d f htubes have a lifetime of 5 years before they are moved to the edge of the pool for cooling.

Summary up to todayy p y A molten salt reactor, MSR, is a Gen IV option, and one is

needed ORNL published all their Molten Salt Reactor reports so

others could rebuild (and develop further) Several groups and individuals worldwide are currently Several groups and individuals worldwide are currently

considering and investigating MSRs and their advantages Now is the time to seek the best design (for UK) Energy Process Developments has been using a grant from

TSB, Technology Strategy Board, of £125,000 to carry out a feasibility studyy yOur conclusion and recommendation for UK build is the

Moltex Simple Salt Reactor

Energy Process Developmentsgy p Supervisory Panel

D k F FRS FRE Di f R h d Derek Fray FRS FREng, Director of Research and Emeritus Professor, Department of Materials Science and Metallurgy University of Cambridgeand Metallurgy, University of Cambridge

Paul A Madden, FRS FRSE, theoretical chemist and Provost of The Queen's College OxfordProvost of The Queen s College, Oxford

Geoff Parks, Senior Lecturer in Nuclear Engineering, D t t f E i i U i it f C b idDepartment of Engineering, University of Cambridge.

P j DiProject Directorsff h h h Trevor R Griffiths, BSc, PhD, CSci, CChem, FRSC, MICorr,

MESCMSE, initially in Metals and Ceramics, Oak Ridge N ti l L b t ti d f L d U i itNational Laboratory, now retired from Leeds University, Department of ChemistryJ T li MA(O ) CE MCIWEM Jasper Tomlinson MA(Oxon) CEnv MCIWEM AMIMechE, physicist and hydrologist and international independent consultantindependent consultant

Rory O’Sullivan CEng BA BAI MIMechE 1st class honours in Mechanical and Manufacturing Engineering fromin Mechanical and Manufacturing Engineering from Trinity College Dublin

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