DCOM

1
Status of He-EFIT Design Pierre Richard J.
F Pignatel G. Rimpault
2
Outline

• Recall of the Design Approach
• Main Issues Addressed since the February
  (Bologna) Meeting
• Updated Table of He-EFIT Main Characteristics
• Presentation of the current core design Core,
  Spallation module, Power Conversion Cycle
• DHR Approach
• Conclusions Next steps

3
He-EFIT Design Approach
1 Spallation module design using the outcome of
the PDS-XADS Project 2 - Define the Proton Beam
Intensity (for a maximum proton energy of 800
MeV), the reactor power and the Keff (assuming
the potential reactivity insertions and burn up
swing which have to be checked later)  3 -
Design the core taking into account the design
objectives (MA burning, Keff considerations,)
and the core design constraints (Fuel
composition, cladding composition, pressure
drops,)-----------------------------------------
----------------------------------------- 4 -
Define the approach for the DHR  and design the
DHR main components (blowers, HX,)  5 - Design
the primary system 6 - Design the Balance of
Plant and Containment and implementation of the
plant (cooling loops, confinment building,
) Steps 2 and 3 require iteration loops with
neutronics, T/H and geometry considerations ?
Required some time
4
Evolutions since the Bologna Meeting (1/3)

• Proton beam characteristics
• Energy changed from 600 MeV to 800 MeV which is
  currently considered as an upper limit over 800
  MeV, the radio-toxicity increase rapidly
• Need for higher proton beam intensity 18-22 mA
  instead of 10-20 mA
• Plant Efficiency
• First Assessment made at CEA with Tin/Tout
  400/550 C
• AMEC/NNC incentive to increase the ?Tcore from
  150 C to 200 C Decision from the Lyon meeting
  (03/06) Tin/Tout 350/550 C
• Plant efficiency increased to 43.3
• Fuel Characteristics
• CERCER (MgO matrix) limit temperature at nominal
  conditions decreased from 1860 C to 1380 C
• CERMET (Mo matrix) considered as back up solution
  (decision from the Cadarache meeting in June)
• S/A Characteristics
• S/A Outer width over flats reduced from 162 mm to
  137 mm target size corresponding to 19 S/A at
  the center of the core

5
Evolutions since the Bologna Meeting (2/3)

• Core Design
• Core power decreased to 400 MWth (600 MWth
  before)
• 3 zones core with different pin diameters
• Peaking factors
• Total peaking factor changed from 1.61 to 1.839
  iteration with neutronic calculations
• Adaptation to He-EFIT of the objectives defined
  by the Specialist Meetings (March-June 2006)
• 42 Kg MA burnt par TWhth
• Flat Keff versus BU
• Reasonably low current requirement lt 20 mA
• Low pressure drop lt 1.0 bar
• Clad temperature limit lt 1600C (transient), lt
  1200C (nominal)
• Coolant speed lt 50 m/s
• Others Wrapper Thickness, Number of grids,

6
Evolutions since the Bologna Meeting (3/3)

• Cross-check with FzK and modifications of the
  correlations for Heat Exchange Coefficients,
  Core Pressure Drops and Fuel Conductivities
  (According to DM3 recommendations)
• Rather good agreement
• Core composition ?f lt 0.05
• Fuel Max Temperatures ?Tlt 20 C
• Cladding Max Temperatures ?Tlt 6 C
• Pressure drops incoherency in the Dh
  calculationsbut small consequences ?(?P) lt
  0.034 bar
• Safety
• Pressure drop limited to 1 bar for the core and
  1.5 bar for the whole primary circuit
• ? Provisional value to be checked by appropriate
  transient calculations
• DHR strategy - Comparison of different two
  approaches XADS-like approach / GCFR
  approach

7
Main Characteristics of the Gas-Cooled EFIT (1/3)
8
Main Characteristics of the Gas-Cooled EFIT (2/3)
9
Main Characteristics of the Gas-Cooled EFIT (3/3)
10
Current Design

• A three zone core has been preliminarily studied
  
• Zone 1 (inner) 45 MWth, 42 sub-assemblies
• Zone 2 (intermediate) 165 MWth, 156
  sub-assemblies
• Zone 3 (outer) 191 MWth, 180 sub-assemblies
• The main hypothesis and/or design objectives
  accounted are the following
• Core heigth 125 cm
• External width over flat 137 mm
• Fuel (fuelmatrix) fraction in the diffrent
  zones 11, 21.5 and 35 (for respectively
  zone 1, 2 and 3)
• Matrix volmue fraction in the fuel pellet 50
• - The total form factor was assumed to be the
  same in the three zones (1.839)
• Remarks
• 1 - Core pressure drops are not equilibrated (too
  many design constraints). They are respectively
  0.84, 0.74 and 1 bar in zone 1, 2 and 3 ? some
  gagging will be necessary
• 2- The pellet diameter in zone 1 is rather small
  (2.3 mm). If this induces some problem, the
  number of pin rows per S/A can be reduced to 11
  row per S/A.

11
Current Design 50 MW/m3 (1/2)
12
Current Design 50 MW/m3 (2/2)
13
Cold Window Concept (1/2)
14
Cold Window Concept (2/2)
15
Power Conversion Cycle AMEC-NNC Assessment

• Assumptions
• Keeping the indirect Supercritical CO2 cycle with
  re-compression
• CO2 remains super-critical CO2 characteristics
  above the Critical Point (74 bar/32 C). This
  avoids the presence of water in the compressors
  (badly known behaviour of the components)
• CEA Low Heat sink Temperature considered too
  restrictive 16 C ? 21 C
• Parametric study on the core inlet temperature
  /- 50 C

16
Power Conversion Cycle
Main Compressor
Auxiliary Compressor
Turbine
? ? 43.3
17
Decay Heat Removal - Approach

• Goal
• Compare different strategies
• Active/Passive
• Guard Containement/No guard Containment
• Background
• GCFR Approach
• PDS-XADS (He-cooled XADS)

18
Schematic of DHR system (CEA initial proposal)

pool


Exchanger 2


Secondary loop

H2

Exchanger 1

dedicated DHR loops

• 3 loops of DHR
• 3 pools
• 1 guard containment

H1

Guard
containment

core

19
DHR (CEA studies)
20
GFR STRATEGY (CEA Approach)

• For the GFR 2400MWth
• -The high back-up pressure strategy (25Bar) is
  not kept
• -for GFR the intermediate back-up pressure
  strategy (5 Bar) is studied
• -Back Up solution The full depressurisation
  (1Bar) (still not studied)

21
PDS-XADS
Basic Reactor options Reactor power
80MWth First core classical FBR fuel U-PuO2
(35 Pu max) Accelerator designed for
600MeV/6mA but can be upgraded to 800MeV/10mA
Core and Target Unit designed for 600MeV/6mA
Separated target liquid Primary circuit He
DHR Strategy

• No Guard Containment
• Full depressurization 1 Bar
• Integrated SCS (but only 2 MWth to be removed by
  each SCS)

22
PDS-XADS SCS Design

• Integrated SCS
• (Electric Power 55kW)

23
DHR for EFIT

• For He-EFIT
• The PDS-XADS solution seems better
• Proton beam ?complexity ? Guard containment not
  keep

• If the full depressurization is chosen, a
  strategy must bedefined
• The blowers must work 1 to 70 Bars Requires
  High Power and a complex Blower Design (or 2
  systems 1-10 bars and 10/70 bars? )
• OR
• Blowers can work only at low pressure
• ? Acton for fast depressurization System
  systematically used (safety)
• ? SIMPLIFICATION of procedures

• System implementation
• 3 DHR loops designed for 100
• 2 Solutions Loops integrated on the
  vessel/Ex-vessel loops

24
Conclusions (1/2)

• Current Design
• A three zone core has been preliminarily studied
  
• Zone 1 (inner) 45 MWth, 42 sub-assemblies
• Zone 2 (intermediate) 165 MWth, 156
  sub-assemblies
• Zone 3 (outer) 191 MWth, 180 sub-assemblies
• The main hypothesis and/or design objectives
  accounted are the following
• Core height 125 cm
• External width over flat 137 mm
• Fuel (fuelmatrix) fraction in the different
  zones 11, 21.5 and 35 (for respectively
  zone 1, 2 and 3)
• Matrix volume fraction in the fuel pellet 50
• - The total form factor was assumed to be the
  same in the three zones (1.839)
• DHR Approach under discussion

25
Conclusions (2/2)

• Next steps
• Detailed neutronic calculations
• Neutron source behaviour by the mean of MCNPX
  Calculations
• Core neutronics by the means of MCNPX and ERANOS
  calculations.
• Even if the current core design is not fully
  defined, He-EFIT main characteristics (core
  power, main core dimensions) are sufficiently
  defined to go ahead with
• Safety Approach/DHR strategy
• Pre-sizing of the DHR loop components (AREVA ??)
• CATHARE/SIM-ADS modelling (CEA/FzK ???)
• Remontage (AREVA)
• ? Dissemination of the main He-EFIT design
  characteristics Iteration with the partners