ELECTRA-FCC: An R&D centre for Generation IV systems in Sweden. Janne Wallenius Professor Reactor Physics, KTH

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1 ELECTRA-FCC: An R&D centre for Generation IV systems in Sweden Janne Wallenius Professor Reactor Physics, KTH

2 What do Generation IV nuclear systems offer? Recycle of U-238 from spent fuel and enrichment plants. Increase in fuel resources by a factor of 100. The uranium already mined would last for thousands of years. Recycle of high level long lived waste. Less than 1% of the danger would be left underground. A reduced time for storage of residual waste. After less than 1000 years, a human intrusion would have acceptable consequences. An increase in capacity of the Swedish repository by a factor of six.

3 How can we achieve this? Build new fast neutron reactors with sodium or lead coolant + Recycle facilities for plutonium, americium & curium + Fuel fabrication facilities for plutonium, americium & curium + Safeguarde measures to ensure non-proliferation plutonium + Storage of residual waste for less than 1000 years = Generation IV systems

4 What is ELECTRA-FCC? A low power fast reactor Inert matrix nitride fuel Heat removal by100% natural convection of liquid lead A recycle facility & a fuel fabrication facility

5 Which purposes would ELECTRA-FCC serve? Test bed for LFR technology (1st pure LFR!) Research on fast reactor dynamics R&D on fuel recycle & manufacture Training of LFR operators (MYRRHA, ALFRED) Education of nuclear engineering students

6 Why lead? Sodium is the industrially mature technology for Gen-IV reactors ASTRID - a 600 MWe sodium fast reactor will be built in France Lead fast reactors provides some distinct advantages No rapid exothermal reaction with water High boiling temperature Potential for decay heat removal by natural convection Chemical and physical retention of core melts

7 Who else builds in lead? SVBR, 100 MWe Russian LBE cooled reactor with MOX fuel, for commercial electricity production in remote areas. Construction to start in BREST, 300 MWe Russian LFR with (U,Pu)N fuel. SVBR-100 MYRRHA, 100MWth Belgian LBE cooled multipurpose facility, developed by SCK CEN Hyperion, 25 MWe LBE cooled battery with UN fuel. Prototype planned for Savannah River site. ALFRED, 130 MWe European LFR demonstrator. Romania official host candidate. MYRRHA

8 Choice of steel for fuel cladding tubes: Creep, corrosion and radiation resistance Sandvik developed a creep & radiation resistant austenitic steel with 15% chromium, 15% nickel and 0.4% titanium for use in Phenix. This steel is qualifed for use in fast reactors and is the reference for ASTRID, MYRRHA & ELECTRA. Sandvik can revive production. Austenitic steels dissolve in lead at 550 C. KIT solution: Coat austenitic steels with Fe-Cr-Al-Y, and form surface alloy by electron beam treatment (GESA) FeCrAlY coating Austenitic steel GESA treated coating Austenitic steel GESA treated steel after 8000 hours in LBE at 600 C

9 Why natural convection? Pump impeller blade in LFRs will operate at 10 m/s relative velocity to the coolant At elevated temperatures, conventional steels are severely eroded even at optimal oxygen conditions T91 MYRRHA & SVBR solution: use LBE coolant & low temperature operation of pump Solution for pure lead yet to be identified ELECTRA operates on natural convection

10 ELECTRA: reference fuel Thermal conductivity [W/m/k] Only inert matrix fuels yield core sizes small enough for natural convection to work (Pu 0.4,Zr 0.6 )N T [ C] CONFIRM (Pu0.4,Zr0.6)N basis for reference design + High thermal conductivity - 15 times larger than (Pu,Zr,Y)O2 + Behaves well under irradiation (CONFIRM experiment in The Netherlands) + Good compatibility with lead + Acceptable stability at accident temperatures + Good solubility in nitric acid of irradiated fuel

11 ELECTRA: reference design Nuclear Technology, March fuel pins, Dclad = 12.6 mm (Pu0.4,Zr0.6)N fuel with Pu from spent UOX Fuel column height: 30 cm Active core dimensions: ~ 30 x 30 cm Reactivity compensation using 6 rotating drums with B4C initially facing core 10 B4C/steel drum Shutdown assembly

12 ELECTRA: Natural convection 0.5 MW of power may be removed by natural convection of lead, if Δ T ~ 100 K 3 m Stability of flow requires sufficient flow resistance & a large cold leg area. Elevation of heat exchanger ~ 2 meters Vessel dimensions: ~ 3.0 x 1.5 meters. Flow stability under start-up and transients to be investigated using electrically heated mock-up. 1.5 m

13 Choice of location Potential sources for plutonium: Separated PuO2, owned by OKG, residing in Sellafield. On-site eparation of spent fuel residing in CLAB (Oskarshamn) Oskarshamn is the simplest solution. OKG has pointed out potential location inside physical protection Municipality of Oskarshamn has access to SKB funds of potentially up to 1200 MSEK.

14 Cost estimate Reactor: 300±50 MSEK (cost based on 700 kw lead-bismuth spallation target experiment in Switzerland & water reactor costs) Fuel fabrication facility: 100±50 MSEK (cost based on Swiss project) Recycle facility: 300±50 MSEK (cost based on US hot cell data) R&D: 300±50 MSEK Total ~ 1000±200 MSEK

15 Timing Fuel qualification is rate determining factor Qualification program for (Pu,Zr)N may last 10±2 years Design of reactor, design and licencing of fuel cycle facilities Licensing of reactor Reactor build Construction and operation of fuel cycle facilities Design, build and operate electrically heated mockup version of ELECTRA Irradiation tests of fuel and cladding (single pins) Fuel bundle irradiations

16 Summary Lead fast reactors may offer a safe and economic Generation IV solution ELECTRA may provide proof of principle for LFR technology, using inert matrix nitride fuel, alumina protected steel and natural convection of lead coolant. Fuel recycle & manufacture facility most conveniently located in Oskarsham Cost estimate ~ 1000 ± 200 MSEK Start of operation: 2023 ± 1 year