Early Operational Experience of the Cold Neutron Source on OPAL - - PowerPoint PPT Presentation

Early Operational Experience of the Cold Neutron Source on OPAL Reactor

Weijian Lu Australian Nuclear Science and Technology Organisation

October 2009

The OPAL Reactor

• 20 MW multi-purpose research reactor
• Compact core (MTR-type fuel)
• Light water cooled and moderated
• Heavy water reflected
• Radiopharmaceutical Production
• Neutron Beam Research

The OPAL Reactor

CORE PCS PIPE CNS CRYO-PIPE

Important Contract Requirements Fulfilled

• 20 litres of single phase liquid deuterium at

below 25 K

• Cryogenic power specification –

5 kW

• A standby mode –

reactor operating at full power without cryogenic cooling

• Cold neutron flux at reactor face (~low 1010

n·cm-2 ·s-1) and through neutron guides (~mid 109 n·cm-2 ·s-1)

An International Project

• INVAP, Argentina – overall design,

project management, CNS process systems

• PNPI, Russia – In-pile (vacuum

containment and thermosiphon), deuterium gas

• Air Liquide, France – helium cryogenic

system

• Mirrortron, Hungary – neutron guides

Mechanical Design

Support Tube CNS Vacuum Containment Beam Tube Reactor Face

Thermosiphon Model

LD2 He inlet HX flow He outlet flow He inlet MC flow

Thermosiphon

Heavy Water Outlet Pipe Heat Exchanger Moderator Chamber Neutron Reflector Heavy Water Inlet Pipe Flange Helium tube Deuterium Pipe Bayonet Connectors

Moderator Chamber with Displacer (AlMg5)

MCNP 3-D Model

Timeline

Jan 03 Jan 04 Jan 05 Jan 06

CNS Thermosiphon prototype tests CNS-RCS factory acceptance tests On-site CNS-VS, CNS-MS, CNS-GBS tests CNS-RCS integration with in-pile assembly (cryogenic) CNS Liquefaction of deuterium OPAL criticality and then 20 MW On-site CNS-RCS tests with bypass

Jan 07

OPAL Cold Commissioning commences CNS Hot Commissioning

Jan 08

CNS Routine operation

Heat Load Measurement

• Heat load measured by steady state

helium thermal balance => 4 kW

• Excellent agreement between

measurement and theoretical prediction (Δ<100 W)

• Single phase moderator verified
• (See conference proceeding for details)

Heat Load vs Reactor Power

Measured Heat Load on the CNS In-pile by Cryogenic Helium Thermal Balance Linear fits indicate nuclear heat load (W/MW) by the slope and non-nuclear heat load by the

• ffset (W)

y = 85.666x + 363.1 R2 = 0.9988 y = 1 80.49x + 387.57 R2 = 0.9999

0.00 500.00 1000.00 1500.00 2000.00 2500.00 3000.00 3500.00 2 4 6 8 10 12 14 16 18 20

Reactor Power (M W)

Liquid Deuterium Gas Deuterium Linear (Gas Deuterium) Linear (Liquid Deuterium)

Single-Phase Verified

LD2 Heat Load

75.00 77.00 79.00 81.00 83.00 85.00 87.00 89.00 91.00 93.00 95.00 25 25.5 26 26.5 27 27.5 28 28.5 29 29.5 30 30.5 31

He Outlet Temp. (K)

0.885 0.905 0.925 0.945 0.965 0.985 1.005 1.025 1.045 1.065 1.085 1.105

Normalisation to Saturation

Saturation Point

Flux Contract Performance

Performance Acceptance Criteria (RF = reactor face) (NGH = neutron guide hall) OPAL measured flux (20 MW equiv) ( in n/cm2/sec) Thermal neutron flux at RF for TG4 [1] 4.0 x 1010 Thermal neutron flux in NGH for TG1(TG3) [1] 3.3 (2.8) x 109 Cold neutron flux at RF for CG4 [2] 2.5 x 1010 Cold neutron flux in NGH for CG1(CG3) [2] 5.9 (6.4) x 109

[1] E < 100 meV [2] E < 10 meV

Operation Issues (positive)

• Standby Operation (SO) mode and Normal

Operation (NO) mode at full reactor power

• Two way transition
• SO mode greatly enhances reactor

availability – hot commissioning on time made possible

• CNS safety control –

30-minute fast LD2 evaporation manoeuvre after CNS trip to beat xenon poison-out

Operation Issues (negative)

• Repeated cryogenic system failures

affecting CNS availability

• Turbine and compressors
• Mechanically demanding
• Sensitive to process purity
• Complex logic in the protection system
• Preventing undesirable pressure and

temperature transients

• CNS specialist intervention often required