electra-fcc: an r&d centre for generation iv … energy conference, march 29, 2012 electra-fcc:...

Chalmers energy conference, March 29, 2012

ELECTRA-FCC: An R&D centre for Generation IV systems in Sweden

Janne WalleniusProfessor

Reactor Physics, KTH


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.


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


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


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


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


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 2017.

BREST, 300 MWe Russian LFR with (U,Pu)N fuel.

MYRRHA, 100MWth Belgian LBE cooled multi-purpose 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.

SVBR-100

MYRRHA


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)

Austenitic steel

FeCrAlY coating

Austenitic steel

GESA treated coating

GESA treated steelafter 8000 hours in LBE

at 600°C


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

MYRRHA & SVBR solution: use LBE coolant & low temperature operation of pump

Solution for pure lead yet to be identified

ELECTRA operates on natural convection

T91


ELECTRA: reference fuel

Only inert matrix fuels yield core sizes small enough for natural convection to work

(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

400 600 800 1000 1200 1400 16000

10

20

30

40

T [°C]

Thermal conductivity [W/m/k]

(Pu0.4,Zr0.6)N

CONFIRM


ELECTRA: reference designNuclear Technology, March 2012.

397 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

Shutdown assembly

10B4C/steel drum


ELECTRA: Natural convection

0.5 MW of power may be removed by natural convection of lead, if Δ∆T ~ 100 K

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

3 m


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.


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


Timing

Fuel qualification is rate determining factor

Qualification program for (Pu,Zr)N may last 10±2 years

2013 2017 2020

Design of reactor, design and licencing of fuel cycle facilities

Irradiation tests of fuel and cladding (single pins)

Design, build and operate electrically heated mockup version of ELECTRA

Licensing of reactor

Construction and operation of fuel cycle facilities

Fuel bundle irradiations

2023

Reactor build


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

electra-fcc: an r&d centre for generation iv … energy conference, march 29, 2012 electra-fcc:...

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