CONTENTS

FIGURES

Figure 1. VHTR with electricity and hydrogen product ion alternatives 10

Figure 2. L o op-t y p e JSFR (1500 MWe) left and pool-t ype KALIMER (600 MWe ) right. 13

Figure 3. SC WR pressure vessel baseline alternative 16

Figure 4. 1200-MWe GFR primary s y stem and reactor cutaway 18

Figure 5. LF R options: E LSY (600 M We) left, and SSTAR (20 MWe) right 20

Figure 6. TMSR core volume (left) and reactor cross section (right). 2 2

TABLES

Table 1. Overview of the si x Generation IV sy stem s. 3

ACRONYMS

AHTR advanced high-te m peratur e reactor AVR Arbeitsgemeinschaft Versu c hsreacktor ELSY European lead-cooled s y st em

EMWG Econom ics Methodolo g y Working Group ETDR experi m e ntal technolog y dem onstration reactor GFR gas-cooled fast reactor

GIF Generation IV International Forum

GTHTR gas turbine high-tem p er ature reactor (J a p an) GT-MHR gas turbine modular helium reactor

HTR high-tem p era ture reactor

HTR-PM high-tem p era ture reactor–pebble bed m o dule HTTR high-tem p era ture engineering test reactor IAEA International Ato m ic Energy Agenc y

LFR lead-cooled fast rea c tor

LWR light water reactor

MA minor actinide

MSR m o lten salt reactor

NGNP Next-Gener at ion Nuclear Plan

NHDD nuclear hydro g en develo p m ent and dem onstration O&M Operations & Maintenance

PBMR pebble bed modular reactor QMS qualit y m a nagem e nt sy stem R&D resea rch and developm ent

SCWR supercritical water- cooled reactor SFR sodium -coole d fast reactor

SSTAR sm all secure t r ansportable autonom ous reactor THTR thorium hochtem perature reaktor (Germany ) VHTR very high-tem p e rature reactor

GIF R&D OUTLOOK FOR GENER A TION IV NUCLEAR ENERGY SYSTEMS

1. AN ESSENTIAL ROLE FOR NUCLEAR ENERGY

The world’s populati on is expected to expand from 6.7 billi on people toda y to over 9 billi on people by t h e y ear 20 50, all striving for a better qualit y of life. As th e earth’s pop ulation gr ows, so does the dem a nd for energy an d th e benefits that it brin gs: improved st anda rds of living, better health and longer life expectancy , i m proved literacy and opportunit y , and ma ny ot hers. Sim p ly expanding t h e use of energy along the same m ix of toda y’ s pr oducti on opti ons, how ever, does not satisfactori ly address concerns over cli m at e change and depletion of f o ssil resources. For the earth to support its population while ensuring t h e sustainability of hum anity’s developm en t ,we m u st incr ease the use of energy supp lies that are clean, safe, cost effective, and which c ould serve for both basi c electricity pro d u ction and ot her primary e n erg y needs. Prom i n ent am ong these supplies is nuclear energy .

There is currentl y 3 70 GW e of nuclear power capacity in operation around t h e world, pr oduci ng

3000 TWh each y ear—15% of the world’ s electricity —the largest share provided by any non- greenhouse- gas-em itting source. This reduces significantly the envir onm ental i m p act of today’ s electricity generation and affords a greater divers ity of electric ity generation that enhances energy security.

The im portan ce of reducing greenhouse gas em issions is now uni versally recogni zed, and numerous strategies and scenarios ar e proposed i n order to achieve m o r e sustainable future energy suppli es. In the majority of these, the prospects ar e good for nucl ear energy’ s gr owth. For exam ple, the 2008 World Energy Outlook forecasts an additional 250 GWe of nu clear capacit y by 2030 in a scenario that would stabilize the atm o sphere at 450 ppm CO 2 and thereb y l i m it global warm i ng to 2°C above pre-industrial levels. Of course, if other forms of clean energy ca nnot be deplo y e d in sufficient am ounts, nuc lear m u st be ready t o do m o re to com p le ment them well into the future.

Many of the world’s nati ons, both industrialized a nd developin g , are driving th e growth of n u clear energy . Som e 43 new uni ts are under construction in 11 coun tries, and m o re are preparing to m ove forward. They are confident that nuclea r energy is a va luable option for their ener gy security in the future. However, challenges still exist to fu rther large-scal e use of nuclear energy : (1) nuclear energy m u st be sustainable fr om the st andpoint of its ut ilization of nuclear fuel resources as well as the m a nagem e nt and disposal of nuclear waste, (2) the units m u st opera te reliably and be econo m icall y com p etitive, (3) safety m u st remain of param ount im portance, (4) deploy m e nt m u st be undertaken in a manner that will reduce the risk nuclear weapons proliferation, ( 5 ) new tec hnologies shoul d help m eet anticipated fut u re needs for a broader range of energ y products be yond electric ity, and (6) go vernments need to supp ort the revitalization of their nucle ar R&D infrastructures. Th e first four are the m a jor goals of Generation IV; the latter two have beco m e increasingly im portant in recent y ears.

1.1 Meeting the Challenges of Nuclear Energ y ’s Essential Role

To m e et thes e challenges and develop future nuclear energy s y ste m s, the Gener a tion IV International Forum (GIF) is undertaking necessary R&D to develop the next generation of innovative nuclear energy sy stems that can supplement toda y’s nuclear plants and transition nuclear energy into the long term .

Generation IV nuclear energ y s y stems com p rise the nuclear reactor and its energy conversion sy stems, as well as the necessary facilities for th e entire fuel cy cle from ore extr action to final waste disposal.

Generation IV sy stems can be broadl y divided i n to f ast and ther mal reactors th at address the above challenges with differing e m phasis and technolog y (S ection 2).

Toda y , m o st countries use the once-thro ugh fuel c y cl e, whereas a few close the fuel cy cle b y p a rtial recy cling. Re cy cling (using either single or m u ltip le passes) r ecovers uraniu m , plutonium , and other transuranics f r om the spent fuel and uses it to m a ke ne w fuel, thereby producing m o r e energy and reducing the need for enrichment and m i ning. Rec y cling in a m a nner that does not produce separated plutonium can further avoi d proliferation risks. Howeve r, the once-through fuel cy cle is still often viewed as the m o st com p etitive given the existing supplies of uranium , though it is expected that views will change as supplies beco m e scarc e r and the cost of mai n taining an open cy cle ex c eeds that of a closed cy cle. With recy cling, other benefits ar e rea liz ed: the high-level radioactive res i dues occupy a

m u ch-reduce d volum e, an d their long-ter m burden can be significantly reduced (decay heat and radiotoxic inventory ) . Furtherm ore, t h ey can be processed into a resist ant and durable waste form for di sposal. Of course, recy cling the l ong-l ived elem ents, especially th e higher actinides that can be transm uted in fast reactors, a c hieves maxi m u m r e duction.

Even before the cost of CO 2 is taken int o account (for exam ple, through em ission s trading schemes), the cost of nuclear power generation in m a ny countries is com p etitive with the cost of producing electricity from CO 2 -emitting coal or natural gas. On the other ha nd, advanced nuclear energy sy stem s m u st address the escal ating construction costs as sociat ed with new nuclear plants. Once again, a m a jor R & D effort is needed to dev e lop advanced designs that reduce capita l costs and construction times.

Overall, the s a fety and environm ental re cord of presen t-da y nuclea r plants is excellent. Nevert heless, the safety of nuclear power wil l be increased ; that of adva nced sy stem s will be addressed through a clear and transparent sa fety approach that arises fr om a co m p re hensive and rigorous R&D program .

Fissile materi als within civilian nuclear power progra m s are well safeguarded against exploit a tion by their host states be cause of an ef fective international sy ste m of controls and m onitoring. Nevertheless, it is desirable for safeguards re gimes and intrinsic nuclear design characteristic s for future nuclear fuel cy cles and nuclear materi als to a c hieve an even higher degr ee of protection from the diversion or co vert production of nuclear m a terials. Current-generation pl ants have robust designs and added precautions against sub-n a tional, non- h o st-state threats of sabot age and nuclear material theft, includi ng acts of terrorism . Future nuclear energy s y stems will provide even greater phy s ical prot ection against such threats.

Most Generat i on IV s y stems ar e ai med at R&D adva nces that ena b le high operating tem p er a tures. This will allow greenhouse-gas-free nuclear energy to be more broadl y s ubstituted for fossil fuels in the production of hy drogen and process heat.

Finall y , with regard to the challenge of maintaini ng t h e R&D infrastructure, the Forum strongly supp orts the coordinat e d revitalization of nuclear R&D infrast ructure worldwide to a level that would once again m ove a new generation forward quickl y .

Generation IV nuclear energy s y stems will take anot her two to three decades to advance towards our am bitious go als. This Generation IV R & D Outlook provides a vi ew of what the GIF m e mbers hope to achieve collectively i n the next five y ears. As al way s , each Foru m mem b er is free to choose the sy stems that the y will advance. The various sections introdu ce the sy stem s th at we ar e advancing and the goals that we are working towards. Th e y also describe the horizontal work we do in support of all our technologies, highli ghting vital areas su ch as quality management, sy stem integration and assessment, and collaboration s around the world.

Our resolve is to prom ote future nuclear energy s y ste m s that enabl e the safe and sustainable worldwide growth of nu clear energy well into the f u ture. The Fo rum is excited about t h e pr ospects for nuclear energy and believes our plans can make a consi d erab le contribution to its l ong-term success.

2. FINDI NGS OF THE ROADMAP

2.1 Generation IV Nuclear Energy Sy stems

The Generation IV Ro adm ap exercise c u lm inated in the selection of six Generati on IV s y ste m s. 1 The basis for the selection of six sy stem s w a s to:

 Identif y s y stems that m a k e significant advances towar d the technol ogy goals

 Ensure that the i m portant missions of electricity gene ration, hydrogen and pr ocess heat production, and actinide manage ment may be adequate ly addressed by Generation IV s y stems

 Provide som e overlapping coverage of capabilities, because not all of the s y stems m a y ultim at ely be viable or attain their performance objecti v es and attrac t commer c ial deploy m e nt

 Acco mmodate the range of national prio rities and interests of the Forum .

The effort today in Generation IV follow s through on t h is basis, with the aim of developing an d delivering via b le, high-performance sy stem s in a few decades. The six sy stem s are outlined in Table 1. They are described below after a short introduction of the nuclear fuel cy cle and f o llowed by s u mmari es regarding fue l cy cles and overall sustainabilit y , m i ssi ons and econom i c outlook, the approach to safety and reliabilit y, and proliferation r esistance and phy s ical protection.

Table 1. Overview of the six Generation IV sy ste m s.

2.2 Fuel C y cles and Sustainability

The choice of nuclear fuel cy cle has a large im pact on the long-ter m sustainability of the nucl ear energy option . A onc e-through c y c le is the m o st uranium res ource-intensive and generates the m o st waste in the form of used nuclear fuel, as onl y ½% of the fuel is converted int o energy . However, the am o unts of waste arisings or em ission s (including CO 2 ) are small com p ared to othe r energ y technolo g ies such as fossil fuels. In addition, the ex isting known and estimated additi onal econom ic uranium reso urces are sufficient to support a once-through c y cle at least until late century , according to t h e m o st r ecen t Red Book anal y s i s . 2 In the longer term , bey o nd the latter part of this centur y , urani u m resource avai labilit y also beco m e s a lim iting factor unless breakthroughs occur in m inin g or extraction technologies.

Sy stem s that em ploy a fully closed fuel cy cle w ill reduce repository space and perfor m ance requirements, provided their costs are hel d to acceptable levels. Clos ed fuel cy cles per m it partitioning the nuc lear waste and m a n a ge ment of each fraction with the best stra teg y . Advanced waste manag e m e nt strat e gies include the trans m uta tion of selected nuclides, cost-effective decay -heat manage m e nt, fl exible interim storage, and custom ized waste forms for specifi c geologic re positor y envir onm ents. These strat e gies will reduce the long-li ved radiotoxicit y and decay heat of waste destined for geological repositories by several orders of magnitude. This is accom p lish e d by recovering m o st of the heavy long-lived radioactive ele m ents.

These reducti ons and the a b ilit y t o opti m ally condit i on the residual wast es and manage their heat loads per m it far m o re efficient us e of lim ited r e pository capacity and enhance the overall safety of the final disposal of radioactive was tes.

Because closed fuel cy cles require the partitioning of spent fuel, they have been perceived as i n creasing the risk of n u c lear proliferation. The ad vanced separations technol ogies for Generation IV systems are designed to a void t h e separation of pl ut onium and in corporate other features to enhance proliferation resistanc e an d provide effective saf eguards. In par ticular, all Gene ration IV sy ste m s e m ploy ing recy cle avoid separation of pluto n i u m fro m other actinides and incorporate additional features to reduce the accessibility and weapons attractiveness of m a t e rials at every stage of the fuel c y cle.

In the m o st a dvanced fuel cy cles using fast-spectru m reactors and e x tensive recycling, it m a y be possible to reduce the radiotoxicity of all wastes such that the isolation require m e nts can be reduced by several orders of m a g n itude (e.g., for a time as l o w as 1000 y ears) aft e r discharge fro m the reactor. This would have a beneficial i m pact o n the design of future repositories and di sposal faciliti es worldwide. However, this scenario can onl y be e s tablished through c onside rable R&D o n fuel recy cli ng technol ogy.

2.3 Descriptions of the Generation IV Sy stems

In the following descriptions, viability refers to examining the feasibilit y , integration, and scale up of key technologies (not just t h eir proof of prin ciple), and performance refers to undertaking t h e developm ent of performance data and optimization of the sy stem . These phase s ar e then follow e d by demons tration that involves licen sing and cons truction of a protot ype or de m onstration sy stem in partnership with ind u str y and other cou n tries.

2.3.1 VHTR – Ver y -Hi gh-Temperature Reactor

The VHTR is the next gene ration in the developmen t of high-tem p er ature reactors and is prim ar ily dedicated to the cogeneration of electricity, hydroge n, and process heat for indust ry . H y drogen can be extracted from wate r by using therm o -c he m ical, el ect ro-che m i cal, or hy brid process es. The re actor is cooled b y helium gas and m oderated by graphite with a core outlet tem p erature g r eater than 900°C (with an ultim ate goal of 1000° C) to support the effici ent production of hy drogen by t h erm o -chem i cal processe s. The high outlet te m p erature al so makes it at tr active for the che m i cal, oil, and iron industries.

The VHTR has potential for high burnup (150–200 G W d/tHM), passive saf ety , low operation and maintenance costs, and m o dular constru c tion.

Two baseline options are a v ailable for the VHTR cor e : the pebble bed t y pe and th e prismatic block t ype. The fuel cy cl e will initially be once-thr ough with low- enriched uranium fuel an d ver y hi gh f u el burnup. The sy stem h as the flexibility to ad opt cl osed fuel cy cl es and offer burning of transuranics. Initially , the VHTR will b e developed t o m a nag e the back end of a n open f u el cy cle. Ultim at ely , t h e potential for a closed fuel cycle will be assessed.

The electric p o wer conversion m a y em plo y either a dir ect (heliu m gas turbine) or indirect (gas mixture turbine) Brayton c y cle. In the near ter m , the VHT R wi ll be developed using existing m a teri als, whereas its long-term developm ent will requi re new and advanced m a terials.

The basic technology f o r t h e VHTR has been establishe d in form er high-tem p erature gas react ors such as the U.S. Peach Bottom and Fort Saint-Vrain pl ants as well as the G e r m an Arbeit sge m eins chaf t Versuchsreacktor (AVR) and th orium hochtem peratu re reaktor (THTR) protot ypes. The technolog y is being advanc ed throu gh ne ar- a nd medium-term projects, such as the pebble bed m odular reactor (PBMR), the high-tem p era ture reactor–pebble bed m o dul e (HTR-PM), the gas turbine high-tem p e rature reactor (GTHTR 300C), A N TARES, nuclear hy drogen developm ent and dem onstration (NHDD), the gas turbine m odular helium reactor (GT-MHR) and the Next-Generation Nuclear Plan t (NGNP), led by several plant vendors and national labor atories respectiv el y in t h e Republic of S outh Africa, the People’s Republic of China, Japan, France, the Republic of Ko rea, and the United States. Experi m e ntal reactors such as the high-tem p er ature engineering test reactor (HTTR) (Jap an, 30 MWth) and HTR-10 (China,

10 MWth) support t h is advanced reactor concept de velopm ent, together with the cogeneration of electricity and h ydrogen, a nd ot her nucl ear heat applications.

2.3.2 SFR – Sod i um-Cooled Fast Reactor

The sodium -c ooled fast reactor (SFR) uses liquid sodium a s the rea c tor coolant, allowing high power density with l o w coolant volum e fraction. While th e oxy g en-free environm ent prevents corrosion, sodium reacts che m i c ally with air and water and requires a se a l ed coolant s y ste m .

Plant size options under considerati on range from small, 50 t o 300 MWe m odular reactors to larger plants up to 150 0 M We. The outl e t tem p erature range is 500 –550°C for t h e options, wh ich affords th e use of the materials developed and pr oven in prior fast reactor programs.

The SFR closed fuel cy cle enables regen e ration of fi ssile fuel and facilitates managem e nt of high-level waste—in particular, pluto n ium and m inor actinides. However, this requires that recy cle fuels be developed an d qualified fo r use. Im portant safety f eatures of the Generation IV sy stem include a long therm a l response ti m e , a reasonable m a rgin to cool ant boiling, a pri m ary sy stem that operates near at m o spheric pressure, and an intermedia te sodium sy st e m betwe e n the radioactive sodium in the prim a r y sy stem and the power conversion sy stem. Water/stea m and supercritical carbon dioxide are considered working flu id s for the pow er conversion sy stem to achieve high performance in term s of thermal efficiency , safety , and reliabilit y . Wit h i nnovations to reduce capital cost, the SF R will be econom ically co m p etitive in future electricity m a rkets. In add iti on, the fast neutron spectrum greatly extends the uranium re sources co m p ar ed to therm a l reactors. The SFR is considered to be the nearest-ter m deploy able sy stem for ac tinide m a nag e m e nt.

Much of the basic technology for th e SFR has been established in former fast r eactor programs and is being confir med by t h e u p com ing Phenix end- of-life t ests in France, the restart of Monju in Japan, the lifetim e exten s ion of BN-6 00 and startu p of BN-800 in Russia, and the startup of the China Experimental Fast Reactor scheduled in 2009 .

2.3.3 SCWR – Supercritical Water-Cooled Reactor

The SCWR is a high-tem p erature, high-pressure water -cooled react or that operat es above the ther m odynamic critical point of water (374°C, 22. 1 MPa). Two design options— p ressure vessel and pressure tube—exist for the SCWR. The sy stem needs to assess the technical feasibility of issues (e.g., m a t e rial s, chem istry , and operating conditions) common to both.

The reference plant has a 1 500-MWe po wer level, an operating pre ssure of 25 M Pa, and a reactor outlet tem p erature o f up to 62 5°C. Due to the l o w densit y of supercritical water, a m o d e rator other than the coolant m u st be added to ther m a liz e the core. The SCWR balance-of-plant is considerably sim p lified because the c oolant does not change pha se (boil) in th e reactor. Ho wever, saf ety features si mil a r to those of advanced boiling water reactors ar e i n corporated.

The main advantage of the SCWR is im p r oved econo mics because of the hig h er therm odynamic efficiency (up to about 50% versus 34% for light water reactors today ) and the pot e ntial for plant si m p lification. Im provements in the areas of safety , sustainability , and proliferation resistance and ph y s ical prot ection are being p u rsued b y considerin g several options for designs using therm a l as well as fast-neutron spectra and the use of a cl osed fuel cy cle, including thorium .

2.3.4 GFR – Gas-Cooled Fast Reactor

The GFR is a high-tem p era ture, helium - cooled fast r eactor with a c losed fuel cy c le. It com b ine s the advantages of fast-spectru m sy ste m s wi th those of high-tem p er ature sy stems. The fast spectr u m a ffords m o r e sustaina ble use of uranium resourc es and waste minim ization throug h fuel r ecy cling an d burnin g of long-lived actinides, and th e high tem p erature affords hi gh-therm a l-cy cle efficiency and ind u strial use of the generated heat, e.g., for h y dro g en pr oduction . The reference reactor is a 2400 -MWth/110 0- MWe, helium - cooled sy stem operating with an outlet te m p erature of 850° C using three indirect power conversion s y stems with a co m b ined cy c le. Direct Bray t on c y cle ga s turbines can be considered in a second stage.

The GFR adopts some of the fuel recy cl ing pr ocesse s of the SFR and the reactor technology of the VHTR. The r eactor development approach relies as f a r as possible on the structures, m a t e rials, co m ponents and p o wer conversion sy ste m developed fo r the VHTR. However, R&D bey ond the work on the VHTR is needed, mainly on core des ign and safety approach. Core configura tion options a r e based on pin- or plate-based hexagonal fuel assem b lies or pris matic blocks. Since graphit e -bearing fuel and core materi als ar e not appropriate for a fast re actor, sever al new fuel forms ar e being considered: com posite cera m ic cl ad mixed actinide carbide fuel, or advanced fuel particles .

2.3.5 LFR – Lead-Cooled Fast Reactor

The LFR features a fast-neutron spectrum and a closed fuel c y cle for efficient conversion of fertile uranium . It ca n also be used as a burner of actinid es from spent fuel and as a burner/breeder wit h thorium matrices. An i m portant feature of the LF R is the enhanced safety that results from the choice of a relatively inert coolant provided that issues of the weight and corrosi ve nature of l ead can be overco m e. It has the potential to m e et the electri city needs of re m o t e sites a s well as for large grid-connected power stations.

The designs that are curren tly proposed as opti ons are two pool-t ype reactors, the sm all secure transportable autonom ous reactor (SSTAR) and the European lead-cooled s y stem (ELSY).

The reference design for the SSTAR is a 20-MWe natura l circulation reactor in a transportable reactor vessel. The L F R features m o lten le ad c oolant, a nitr ide fuel containing transura nic ele m ents, a fast spectru m cor e , and a s m all size. These c o m b ine to provi de a unique approach to proliferation resistanc e

by enabling a long core life , autonom ous load followi ng, sim p licity of operation, reliability, transportability, and a hi gh degree of passive safety . C onversion of t h e core ther mal power into electricity at high efficiency ( 44%) is acco m p lished by a supercritical carbon dioxide Bra y ton cy cle.

The ELSY reference desig n is a 600-MWe reactor with m o lten lead coolant. T h i s concept has been under developm ent within the 6t h Euratom Framework Pr ogramme. ELS Y ai m s to dem onstrate the possibilit y of designing a co m p etitive and safe fast critical reactor using sim p le engineered technical feat ures while providi ng f o r minor actinide burnin g .

2.3.6 MSR – Molten Salt R eactor

The MSR fuel is unique in that it is dissolved in t h e fluoride salt coolant. Com p ar ed with solid-fueled fast reactors, ther mal-spe c tru m MSRs have lower fissile i nventories, no radiation da mage constrai nt on fuel burnup, no fabrication of fuel form s, no spent nuclear fuel asse mblies, and a homogeneous isotopic co m position of fuel in the reactor. Thes e and othe r characteristi cs may enable MSRs to gain unique capabilities and com p etitive econo m ics f o r actinide burn ing and ext e nding f u el resources. The technology was partly de veloped in t h e 1950s and 1 960s, when e a rlier MSRs were mainly t h erm a l-neutron-spectrum concepts.

Other new as pects include the use of a Bray ton power cy cle (rather than a stea m c y cle) that eliminates many of the historical chall e nges in building MS Rs as well as the conceptual developm ent of fast spectru m cor es for the MSR that have large negativ e te m p erature a nd void reactivity coefficients—a unique safety characteri s tic not found in solid-fuel fast reactors. In addition, the development of higher tem p erature salts as coolan ts would ope n the MSR to new nuclear and non- nucl ear applications. These salts ar e being considered for intermediate heat tr ansport lo ops wit h in all t ypes of hig h -tem p e rature reactor sy stems (heliu m a nd salt cooled) and for hydr ogen production concepts, o il refineries and shale oil processing facilities, am on g other applic ations. For most of these applications, the heat would have to be transported u p to a kil o m e ter or m o re.

An alternative concept under considerati on in this s y ste m is the advanced high-tem p erature re a c tor (AHTR). The AHTR uses l iquid salts as a coolant but h as the graphite core struct ures and coated fuel particles of the VHTR. The superior heat transport characteristi cs of salts co m p ar ed with helium could enable power densities 4 to 6 tim es higher and power levels up to 4000 MWt h with passive safety .

2.4 Missions for Generation IV Sy stems

While the evaluations of s y stems for their potential to meet all goals were a c e ntra l focus of the roadmap participants, it was recognized that countries would ha ve various perspectives o n their priorit y uses, or missions, for Generation IV sy stems. The following su mmary of missions resu lted from a n u m b er of discussions by the Forum and the roadm a p particip ants. The summa ry defines three major m i ss ion interests for Generation IV: electricity , hy drogen or process heat, and actinide manage ment. All six sy stems have electricity applications. The higher tem p erature sy stems (V HTR, GFR, LFR and MSR) have potentia l applications in h ydrogen production or industrial pr ocess heat for such chem ical processing facilities as petroleu m refi neries. The three fast r eact or sy stem s an d the MSR ha ve the capability to trans m ute act inides for effective wa ste manage ment.

2.4.1 Electricity Generation

The traditional m ission for civilian nucl ear sy stem s h as been generation of electricity , and several evolutio nary sy stems with im proved econom ics and saf ety are likely in the near future to conti nue fulfilling t h is mission. It is expected that Generati on IV sy stems designed for the electricity m i ssion will y ield innovati ve im provements in economics and be cost com p etiti ve in a num ber of market

environm ents , while seeking further advances in saf ety, proliferation resistance a nd phy sical protection, and sustainability . These Generation IV sy stems m a y operate with either an open or closed fuel cy cle that i m proves the use of nuclear fuel and reduces high-level wast e volume and m a ss. Further, it m a y be beneficial to deploy t h ese nearer- and longer-ter m sy stem s sy m b iotically to opti m ize the econom i cs and sustainability of the ensemble. Within t h e electri city mission, two specializations are needed:

 Mature Infrastructure, De regulated Market. These o p tions within Generation IV sy stems ar e designed to c o m p et e effe ct ively with other m e ans of electricity pro duction i n m a rket environ m ents with larger, stable distributi on gri d s; well-deve loped and experienced nuclear supply , service, and regulator y ent ities; and a variety of m a rk et conditions, including hi ghl y com p etitive deregulated or refor m ed mar k ets.

 Limited Nuclear Infrastructure. This option within Generation IV sy stems is de signed to be a ttractive in electricity market environments chara c terized by s m all, so m e ti mes isolat ed, grids and a limited nuclear regulatory and supply /service infrastructure. These environments m ight lack the capability to manufacture their own fuel or to pr ovide m o re than tem porary storage of used fu el.

2.4.2 Hy drogen Production, Cogeneration, and other Non-electricity Missions

This e m erging m is s ion requires nuclear sy stems that are designed to deliver othe r energy products based on the fission heat source or that may deliver a co m b ination of process heat and el ectricity . The process heat is delivered at sufficientl y hi gh temperatures ( likely needed to be greater than 70 0°C) to support steam-reforming, steam electroly s is, or t h erm o chem ical productio n of h y dr ogen, as well as other chem ical production processes. Applicat ion to desa lination for potable water production m a y be an i m portant use for the rejected heat.

In the case of cogeneration sy stem s, the reactor provid es all ther mal and electri cal needs of the producti on park. The dist inguishi ng ch aracteristic fo r this m ission is the high tem p erature at which the heat is delivered. Besides being econom ically co m p etitive, th e sy stem s designed for thi s m ission wo uld need to satisfy stringe nt standards of safety , proli feration resist ance, phy s ical protection, a nd product quality .

For this m issi on, s y stems may again be designed to e m pl oy either an open or closed fuel cy cle, and the y may ultim ately be s y m b iotically depl oy e d to optim ize econom ics an d sustainability.

2.4.3 Actinide Management

Actinide m a n a ge m e nt is a mission with significant societal benefits —nuclear wa ste consu m ption and long-term assurance of fuel availability. This m i ssion overlaps an area that is ty pically a national responsibilit y, namely the disposition of spent nuclear fuel and hi gh-level wast e. Although Generation IV sy stems for actinide mana ge m e nt ai m t o generate el ectricity economically , the market environment for these sy stem s is not y e t well defined, and their requi r e d econom ic performance i n the near term will likely be determ ined b y t h e go vernments that deplo y t h em . Most Generat i on IV s y stems ar e ai med at actinide management, with the exception of the V H TR. Note that the SCWR begins with a therm a l neutron spectru m and once-through fuel cy cle, but m a y ultim ately be able to achie ve a fast spectru m with recy cle.

The m id-term (30–50 y ear) actinide man a gem e nt m i ssi on consists prim arily of li miting or reversing the buildu p of th e inventor y o f spent nuclear fuel from cu rrent and near-ter m nuclear plants. By extracting actinides from spent fuel for irradiation and m u ltiple r ecy cle in a closed fuel cy cl e, heavy l ong-lived radiotoxic constituents in t h e spent fuel are transm ut ed into m u ch shorter-lived or stable nuclides. Also, the intermediate-lived acti n ides that dominate repositor y heat m a n a gem e nt are transm uted.

In the longer ter m , the acti n ide m a nage ment m is s ion can beneficia lly produce excess fis s ile materi al for use in sy stems optim ized for other energy m issions. Because of their ability to use recy cled fuel and

generate need ed fissile mat e rials, sy stems fulfilli ng t h i s m ission could be ver y nat u rally deployed in concert with sy stems for other m i ssions. With closed fuel cy cles, a large expansion of global uranium enrich m e nt is avoided.

2.5 Generation IV Deplo y ment

The objective for Generati on IV nuclear energy s y stem s is to have them availabl e for wide-scale deplo y m e nt before the y ear 203 0. The de plo y m e nt dates anticipated for the six G e neration IV sy stems in the Roadma p assu med that considerable resources wo uld be a pplie d to their R&D. This has proven to be difficult, but a good start has been m a de by the Forum as described in the m o st recent 2008 A nnual Report . Also challenging was the three -y ear period need ed to finalize the legal l y binding agreements covering m u ltilateral R&D contracts.