November, 2008

Lunar Fission Surface Power Design - Relap5 Point Kinetics

D. S. LucasINL

Acknowledgements

• Jim Werner, INL Space Rx Lead

• Juan Carbajo, Lou Qualls ORNL Relap5 Model

• Dave Poston LANL MCNP Reactivity Coefficients, FRINK

• Rich Riemke, INL R5 Code Development

• Cliff Davis, INL R5 Code Development & Modeling

Discussion

• Brief Background

• Deliverables

• Model Responsibilities

• Why Modeling and Simulation

• LANL,SNL,ORNL,INL Models

• Reactor Kinetics Importance

• SQA

• Summary and Recommendations

Background

• Fast Reactor on Moon for Colony• Solar – Not enough Power• Rx - 180 KW Thermal• 40 kW(e) Net Reactor Power• 8 full-power years• Meet allowable dose levels• Meet launch loads• Operate in lunar environment• Minimum reactor module mass and launch envelope• Meet safety and safeguards requirements• Meet reliability requirements

Design Parameters

• Fast reactor (Cat II)

• NaK coolant

• Open lattice core configuration

• Stainless steel reactor structure (SS-316)

• UO2 fuel

• BeO axial reflectors, Be radial reflector

• B4C in Radial Reflector Shim for reactivity control

• Coolant T-in = 850-900 K, T-out =900-950 K (Subject to Change)

Core & Reactor

Pre-Decisional Deliverables• Concept Trade Study• Pre-conceptual Design• Conceptual Design• System models and tools• System reliability assessment• Demonstration of key technology

– Fuel (vendor needed to meet Phase B/C/D schedule)– EM pump– I&C – (drum / sliders – motors, bearings, sensors)– Others?

• Safety assurance (INSRP) strategy• Design and fabrication of components for TDU

Responsibilities

• LANL Overall Core Design

• ORNL Controllers, Heat Exchangers

• INL E&M Pumps, Backup TDU Simulator & Kinetics

• Argonne East – SASYS Model

• SANDIA – Simulink TDU Simulator

• Need Modeling and Simulation to combine with zero power critical tests and non-nuclear full scale system tests

Stir1*

Stir2*

Rad1(66 kWt)

Stir3*

Stir4*

PI2

Rad2

PS3

PS4PS2

PS1

PI1

PwrCond

&Cont

PLR

Bus

(270Vdc)

SolarArray(5 kWe)

Battery(10 kWh)

IHX2

IHX1

Rx

(183 kWt)PP2 PP1

FPS Schematic

NaKTin,pc=825K

dT=30K

H2OTin,rad=413K

dT=25K

100 m

User Loads(40 kW)

CommandsTelemetry

4 x 12 kWe400Vac

* Each Stirling converter includes two linear alternators.

Thot=791K

Tcold=425K

Trad=382K

Tclad=860K

Aux Loads(5 kW)

NaKTout,rx=850K

dT=50K

ORNL Relap5 ModelJuan Carbajo - Modeling and Analysis of a Lunar Space Reactor – ICAPP - 08

Sandia Simulink

LANL FRINK & INL R5 TDU/Simulator Model – Put Reactivity Coefficients in ORNL Model

Reactor Core

In

Out

Pzr

VP

EMPmp

Sec EMPumpNaK

SHot SColdH2OPmp

H2ORad

Reactivity Data

• LANL MCNP ran with different material temperatures

• Keff’s Computed

• Contributions from Fuel, Moderator, Clad, Shields

• Data to R5 Format, Additional Heat Structures for SS Liner, Be Reflector, B4C Shield

• All Shields to be done with R5 Envelope Model

• Feedback from R5 to Neutronics Important

• ORNL Steady State with Neutronics

• Pump Trip Case with/without Shield with Neutronics

• Pump Trip at 200 seconds

• Simulation on PC out to 600 seconds

Pre-Conceptual Results

• Pumps Trip – With and without Radial B4C Shield

• Secondary Pump Trip

• Primary Half Flow

Pump Flow – Both Transients

No Shield Rx Power - Core TemperaturePump Trip

Shield Pump Trip

Secondary Pump Trip Constant HT

Half Flow Primary Pump 2.1 Kg/sec

Mid Core T

Conclusions & Future Tasks

• Model - Testing Heat Structures, Core Kinetics

• Run Limited Transients

• Nestle- Explain?

• Attila – SW Model Check Rx Coefficients

• Independent Review & Document Kinetics

• Give to Sandia & ORNL

• Checking New Geometry Data

• SQA Plan – Transients

• Couple R5 to NASA Glenn Stirlings via Model Center