latest nuclear reactors

Latest nuclear reactors 

The next two generations of nuclear reactors are currently being developed in several countries .

The first ( 3rd generation  ) advanced reactors have been operating in January 1996. Late 3rd generation  designs are now being built .  Newer advanced reactors have simpler design  which reduce capital cost. They are more fuel efficient and are inherently safer. The nuclear power industry has been developing and improving reactor technology for more than five decades and starting to build the next generation of nuclear power reactors to fill technology development.

Several generation of reactors are commonly distinguished. Generation 1 rectors were developed in 1950-60 and outside U.K. none are still running today . Generation 11 reactors are typified by present U.S. and French fleets and most in operation elsewhere. Generation 111 ( and 3+) are advanced reactors. The first are in operation in Japan and other are under construction or ready to be ordered. Generation IV design are still on drawing board and will not operational before 2020 at the earliest. 

About  85% of world nuclear electricity is generated by reactors derived from designs originally developed for naval use. These and other second generation nuclear power units have been found to be safe and reliable, but they are being  superseded by better designs.

Reactor suppliers in North America, Japan, Europe Russia and elsewhere have a dozen new nuclear reactor  designs and at advanced  stages of planning, while other are at a  research and development stage.
The third generation reactors have following advantages
. Standardized design for each type to expedite licensing, reduce capital cost and reduce construction cost.
 . Simpler and more rugged design making them easier to operate and less vulnerable to operational upsets.
. Higher availability and longer operating life typically 60 years.
. Further  reduced possibility  of core melt accidents.
. Resistance to serious damage that would allow radiological release  from are air craft impact.
.Higher  turn up to reduce fuel use and the amount of waste.
.Burnable absorbs (poison) to extend fuel life.

The greatest departure from second generation design is that many incorporate passive or inherent safety features which require no active controls or operational intervention to avoid accidents in the event of  mal function and may rely on gravitated, natural  convention or resistance to high temperatures.

Another departure is that some PWR types will be designed for load following. While most French reactors to day are operated in that mode  to some extent,  the EPR design has better capabilities. It will be able to maintain its out put at 25 % and ramp up to full out put at rate of 2.5 % of rated power per minute  up to 60 % out put and 5 % rated out put per minute  up to full rated power. This means that potentially the unit  can change its out put from 25 to 100 per cent in less than 30 minutes though this may be at some expense of wear and tear.

However certification design is on a national bane , and safety based. In Europe  there are moves towards harmonized requirements for licensing. In Europe reactor may also be certified  according to compliance with European Utilities Requirements (EUR) of generating companies, which have stringent safety criteria. The EUR include Westinghouse AP 1000, Gidropress, AES -92, Areva EPR , GE’s ABWR , Areva Kerene and Westinghouse BWR 90.

European regulators are increasingly requires large reactors to have some kind of core Cather or similar device, so that in a full core melt accident is enhanced provision for cooling the bottom of reactor pressure vessel or simply catching any material that might melt though it, the EPR and WER 1200 have core Cather under the pressure vessel, the AP 1000 and APWR have provision for enhanced water cooling.
In U.S. a number of reactor types  have received design certificate and others are in process.
ESBWR   from GE-Hitachi U.S. EPR  from Areva and U.S. -APWR from Mitsubishi. The  ESBWR is on track to receive certificate about September 2017 and the U.S. EPR  in mid 2012. Early in 2008 the NRC (nuclear regularity commission ) said the beyond these three, six pre -application reviews could possibly get under way by about 2010. These include ACR from Atomic energy of Canada (AECL), IRIS from Westinghouse, PBMR from ESKOM and 4S from Toshiba as well as General  Atomic  GT-MHR apparently. However for various reasons these seems to be inactive.

Joint ventures

The major international initiatives have been launched to define future reactor and fuel cycle technology mostly looking further ahead than the main subjects of this presentation.

Generation IV international forum is a U.S. led grouping to set up 2001 which has identified six reactor concepts for further  investigation with a view to commercial deployment by 2030.   

The IAEA international project on innovation nuclear reactors and fuel cycles (INPRO ) is focused more on developing country needs, and initially involved Russia rather than U.S. though  U.S. has joined it. It is now funded through the IAEA budget.

At commercial level by end of 2006 three major western - Japanese alliances had formed to dominate much of world reactor supply market.

.  Areva  with  Mitsubishi Heavy industries (MHI) in  a major project and subsequently in fuel fabrication
. General Electric with Hitachi as a close relationship . GE Hitachi nuclear energy (GEH)
. Westinghouse had become 77 per cent owned subsidiary of Toshiba ( with SHAR group 20 %)

Details of EPR

AREVA  NP (Formerly Frame tome ANP ) has developed a large ( 4590 Mwt  typically 1750 Mwe gross and 1630 Mwe net ) European Pressurized water reactor ( EPR ) which was confirmed in mid 1995 as well as new standard design for France and received French approval in 2004. It is a  4 loop  design derived from German KONVOI types with features from French N4 and expected to provide  power about 10 per cent cheaper than N4 . It has several active safety systems, and  a core catcher under pressure vessel . It will operate flexibility to following   loads, have fuel burn up of 65 GW D/H and high thermal efficiency 37 per cent and net efficiency of 36 per cent . It is capable of using full core load of  MOX. Availability is expected to 92 per cent over 60 years service life. It has four separate redundant safety systems rather than   passive safety .

India signed agreement with French AREVA for  supplying two EPRs  for their plant to be built in Jaithapur in Maharashtra.