Transmutation of Waste Using Z-Pinch Fusion

October 1, 2009

Ben Cipiti & Gary Rochau

V.D. Cleary1, J.T. Cook1, S. Durbin1, R.L. Keith1, T.A. Mehlhorn1, C.W. Morrow1, C.L. Olson1, G.E. Rochau1, J.D. Smith1, M. Turgeon1, M. Young1, L. El-Guebaly2, R. Grady2, P. Phruksarojanakun2, I. Sviatoslavsky2, P. Wilson2, A.B. Alajo3, A. Guild-Bingham3, P. Tsvetkov3, M. Youssef4, W. Meier5, F. Venneri6, T.R. Johnson7, J.L. Willit7, T.E. Drennen8, W.

Kamery8

1Sandia National Laboratories, Albuquerque, NM2University of Wisconsin, Madison, WI

3Texas A&M University, College Station, TX4University of California, Los Angeles, CA

5Lawrence Livermore National Laboratory, Livermore, CA6General Atomics, San Diego, CA

7Argonne National Laboratory, Chicago, IL8Hobart & William Smith College, Geneva, NY

Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company,for the United States Department of Energy’s National Nuclear Security Administration

under contract DE-AC04-94AL85000.

2

Overview

The Z-Pinch Transmutation study was funding through LDRD funds from FY06-FY07, but the work builds off the Z-Pinch Power Plant Study.

OutlineZ-Pinch Facility

In-Zinerator Concept

Engineering Challenges

Transmutation Results

3

Z-Pinch Facility

FusionTarget

Z-PinchFacility

4

Z-Pinch Operation

Marx generators deliver the pulse of power through water lines to a magnetically insulated transmission line (power plant would require linear transformer driver).

Past operation delivered 1.8 MJ of x-rays to the target in about 5 ns, but Z was recently upgraded, so future work may increase the power delivery.

Using deuterium gas targets, yields close to 4x1013 n per target have been achieved (D-D) ~ 1016 n per target D-T.

5

Sub-Critical Transmutation Blanket

HeatCycle

LeadCoolant

RTL &TargetDebris

AerosolAtmosphere

Tin RTL

ActinideTubes

TransmissionLines

FusionTarget

SteamGeneratorOr IHX

Pump

Gas, Tritium& FP Removal

An actinide blanket surrounds the Z-Pinch target to capture as many of the fusion neutrons as possible. The actinides are contained in a fluid fuel, which is contained in an annular array of tube banksFusion neutrons are used to initiate fissioning of the actinides

A modest 20 MW fusion source is requiredThe actinide blanket produces 3000 MWth

This design burns down waste while at the same time producing a lot of powerA molten lead coolant is used to remove the heat from the actinide tubes and drive a power plant

6

In-Zinerator Power Plant

Linear Transformer Driver

ElectricalPower

GasTurbine

Generator

BraytonCycle

Heat Exchanger

GasRemoval

Fuel SaltReconstitution

Filters

WasteTreatment

ContinuousExtraction

HydrogenGetter

I2, Xe, Kr

FusionTarget

ActinideTubes

RTL

TransmissionLines

(LiF)2-AnF3

Li, AnF3

Pump

7

Chamber Design

Coolant

Fuel Region1.21 m thick

6 m

22.05

4.06 m

4.09 m

Chamber Ends

0.2 m thick

Argon Atmosphere

10 torr

2.15

3.36

Number of Tubes: 19182Pitch: 3.25 cmTube ID: 2.0 cmTube OD: 2.6 cm

8

In-Zinerator Conceptual Design Parameters

Overall ParametersFusion Target Yield 200 MJRepetition Rate 0.1 HzKeff 0.97Power per Chamber 3,000 MWth

Energy Multiplication 150Transmutation Rate 1,280 kg/yrNumber of Chambers 1

RTL & TargetRTL Material Tin (or Steel)RTL Cone Dimensions 1m Ø x 0.1m Ø x 1m HMass per RTL 67 kg (Tin)Tritium per Target 1.35 mg

Chamber DesignShape CylindricalDimension 4.1 m outer radiusChamber Material Hastelloy-NWall Thickness 5 cm

BlanketActinide Mixture (LiF)2-AnF3

Coolant LeadCoolant Configuration Shell & TubeFirst Wall Configuration Structural WallShock Mitigation Argon gas & aerosolCoolant Temperature 950 KHeat Cycle Rankine or BraytonNumber of Fuel Tubes 19182

Extraction SystemsTritium Breeding Ratio 1.1Tritium production 3.8 g/dayFission Product Removal On-Line Removal

9

Engineering Issues

First WallZ-Pinch offers a unique ability to use aerosol sprays in the chamber to attenuate x-rays—this protects the first wall from melting and is only possible because Z-Pinch does not require pristine chamber conditions

Radiation DamageInitial designs had unacceptable radiation damage to the inner chamber wall and actinide tubes. Design changes such as inserting a standoff between the first wall and actinide tubes reduced the maximum dpa to below 50 dpa for all tubes and below 40 dpa for the first wall.

Energy Deposition in the FuelThe fusion and subsequent fission neutron pulse occurs almost instantaneously, resulting in nearly instantaneous energy deposition. The peak temperature rise in the fuel was 150 °C per shot, but further optimization is required to bring this number down.

Actinide Mixture(LiF)2-AnF3 was chosen for its high actinide solubility, ability to breed tritium, somewhat reasonable melting temperature, and non-reactive composition. Unfortunately thermodynamic properties of the material are not known well.

10

Recyclable Transmission Line Engineering Issues

Tin RTL Structural AnalysisA low melting temperature material like tin may make for a good RTL due to the ease of production and collection. RTL fragments in the chamber will melt and can be collected at the bottom.

RTL CostThe In-Zinerator concept requires one RTL every ten seconds.

Steel RTL: $5.40 per RTL or $1.94 per MWhTin RTL: $1.20 per RTL or $0.44 per MWh(Total fuel cost for nuclear reactors is about $5.50 per MWh)

11

Extraction Systems

Design of Extraction SystemsA preliminary design of the continuous fission product and tritium extraction systems has been completed.

Wasteform

Salt toReactor

Actin

ide

Extraction

Actin

ide

Strip

RE

-AE

-A

ME

xtractionWaste

Treatment

Bi-AM Bi-AM Bi-AM

Bi-AM

Salt–BiF3

Salt fromReactor

Bi-Zr

BiRecycle

Salt–BiF3

Salt–BiF3

Salt Salt

Bi-Zr-Am

Zircon

ium

Extraction

Bi-Am-Cm Bi-RE-AE-AM

Salt

Bi

Bi

BiF3 Formation

RE = rare earths; AE = alkaline earths; AM = alkali metals

F2

SaltElectrolysis

Salt

Fuel SaltReconstitution

MakeupLiF-AmF3-CmF3

Salt –Am-Cm

Zircon

ium

Scru

b

N2

N2

(LiF)2-AnF3

@ 44 Kg/min

LN2H2OH, T

He, Br, I, Kr, Xe, H,

T

He, H, T, Kr,

Xe

He, H, T, Kr,

Xe

He, H, T

He

HXHX

HX

High Temp Charcoal

Filter Adsorber

Low Temp Charcoal

Filter Adsorber

Hydrogen Getter

Sparge Tube(s)

HX Multi-stage

He/H2 (from distillation)

Fission Product Separation

Tritium Recovery

12

Modeling

MCNP was used to optimize the baseline design to reach the desired keff, power level, chamber size, tritium breeding, etc.

MCise was used to calculate time dependent burnup rates, fission product production, and isotopic change

ORIGEN was used to then calculate the activity and heat load to determine the net effectiveness of transmutation

13

In-Zinerator Isotope Ratio Change with Time (TRU Burner)

14

1280 kg/yr TRU Burned at 20 MW Fusion Driver and 3000 MW Total Power

15

A Heat Load Reduction by a Factor of 100 is Seen after 200 Years

16

Z-Pinch Technology Roadmap

Breake

ven?

High Yield

Radiat

ion Effe

cts Tes

ting

Full Sca

le In-

Zinerat

orFus

ion Ene

rgy

Demon

strate

Shock

Mitig

ation

Demon

strate

RTL

& Cha

mber S

ealin

g

Demon

strate

Tritiu

m Con

tainm

ent

ZR ZN Transmutation Energy

Demon

strate

LTD D

river

Demon

strate

Targe

t & R

TLPlan

t

Demon

strate

Mod

erate

Rep R

ate

Instal

l Tran

smuta

tion B

lanke

t

2010 2020 2030 2040 2050

Transm

utatio

n Dem

o

on ZN Fac

ility