WP 6.5 HIP for Densification

(1)

WP 6.5 – HIP for

Densification

CHARLIE SCALES NNL

c h a r l i e . r. s c a l e s @ u k n n l . c o m

(2)

WP 6.3

Thermal treatment

WP 6.5

Densification

Work package interactions

CEA - Ashes

USFD – Wet

oxidation sludges

KIPT - Ashes

CEA - Compaction

USFD – HIP

KIPT – HIP / HP

NNL – HIP

WP 6.6

Characterisation

& stability testing

(3)

Scope of work for HIP

§

Densification of materials to form solid wasteforms:

• HIP of ashes from CEA

• Direct densification, and addition of glass additives if required

• HIP wet oxidation sludges

• Likely utilise a glass matrix, possibly a barium alkali-borosilicate glass if wastes

high in sulphates

• HIP of polymeric material

• Likely lower temperature direct ‘WIP’, or using a thermoplastic polymeric binder

(4)

§

Developed in the 1950s at Battelle for fusion bonding metals and has been

used for manufacture of nuclear submarine fuel since the 1960’s

§

Application of temperature and pressure simultaneously using pressurised

inert gas to consolidate the work piece providing good densification

§

Can be used up to 2000°C but typically ceramic wasteform HIPs operate at

1250-1300°C

§

Used industrially for densification of porous materials and processing metal

powders into compact solids, amongst others

§

In development for nuclear waste immobilisation – allows consolidation of

powdered materials (with additives if required) into a solid final product

HIP Technology

(5)

Process steps

§

Calcination

Size Reduction

Blending

Granulation

_HIP

• Calcination or incineration step to remove organics/moisture

• Size reduction step if required

• Blend with precursor material

• Granulate if required to provide free flowing material to fill

HIP can

(6)

§

Fully dense product, usually ceramic or glass ceramic but can be used to compact metallic

and polymer feeds at lower temp

§

High durability of ceramic based materials

§

HIP No volatilisation of RNs within the HIP

§

Significant volume reduction of the feed material

§

Scale-able – trials at small scale have been replicated at full scale

§

Properties of workpiece independent of the consolidation technology

§

Batch process for material accountancy

(7)

Technology demonstrators for current Project

KIPT HIP facility

NNL HIP facility

(8)

Small scale at University of Sheffield

Pressure vessel

Pressure vessel top closure

Thermal barrier

Water jacket

Work piece

§

Wastes are typically dried, then vacuum

sealed into a canister / container

§

Typically can is 316 (1.4401) stainless steel

§

Material pressed into canister, then lid TIG welded

§

Canister held under vacuum at mild temperature

(~300-600 °C) to remove any minor water

§

Vacuum line crimped and sealed

Inactive canister processed at

1250 °C/ 103 MPa/ 4 hrs

(9)

§

HIP used to demonstrate immobilisation of UK streams

§

Clinoptilolite ion exchange material from SIXEP

§

Sludges from reprocessing of Magnox fuel

§

Benefit in mixing clinoptilolite and Magnox sludge, reduces

amount of glass frit required, increases waste loading

§

Small scale trials at UoS, Larger scale trials at NNL

Workington

§

Feeds pre-calcined at > 600°C

§

HIP at 1250°C, 2-4 hrs at 75 Mpa

§

Waste loading > 60%

Theramin Project

USFD (U)

(10)

§

7-8 kg per can

§

Mixed Magnox sludge

simulant, clinoptilolite, glass

frit, minor additions of Cs

₂

O

+ CeO

₂

§

Results consistent with

small scale results at

University of Sheffield

Theramin Project

100% Clino

Consolidated HIP cans

at NNL

(11)

HIP development for Pu disposition at NNL

• Technology under development since 2002 for the immobilisation of

plutonium residues

• Now being developed for immobilisation of PuO

₂

stockpile deemed unsuitable

for MOX

(12)

Other options explored

Encapsulation

in PEEK

Graphite

consolidated

in a glass

Matrix

Encapsulation of

surrogate waste in

copper

(13)

§

No HIPs currently operating for waste

immobilisation

§

ANSTO currently constructing HIP at Lucas

Heights for immobilisation of waste from

radioisotope production

§

NNL developing an option for the

immobilisation of PuO

₂

on behalf of NDA

§

Idaho – remains an option for calcine

immobilisation

Industrial Scale

Large scale HIP product

(courtesy of AIP and GRI

)