Development of a GANEX flowsheet for co-separation of transuranic elements

16 Pages·2015·0.61 MB·English

Development of a GANEX
flowsheet for co-separation of
transuranic elements
Mike Carrott
Introduction
• Minor Actinides (MA) recycling is being considered
as a potential scenario in the development of
advanced fuel cycles
• 2 potential MA recycling scenarios in the EU:
• Heterogeneous recycling - separate recycling of major and
minor actinides
• Homogeneous recycling – recycling all actinides in a
Grouped ActiNide EXtraction process.
• GANEX flowsheet developed under EU Framework
Programme VII ACSEPT project
GANEX Concept
Dissolved
SNF “EURO-GANEX”
An + Ln
U
An stripping Ln stripping
extraction
extraction
FPs Pu, Np, Am, Cm Ln
U
GANEX 1st
GANEX 2nd (TRU) cycle
cycle
Key Requirements for GANEX flowsheet
development
• Identify solvent capable of high Pu loading without third
phase formation
• Pu loadings of at least 10 g/l
• Keep all TRU together (extraction and stripping) to obtain a
TRU product
• >99.9 % recovery of An, < 0.5% Ln loss to An product
• Selective separation of An from Ln
• Control of fission products
• Control of Np extraction and stripping
• Avoid use of redox reagents
• Compatible with centrifugal contactors
• Based on CHON principle
GANEX2- solvent development
TODGA: insufficient Pu(IV) loading capacity ≤ 5 g/L Pu(IV)

Solvent composition (in kerosene) Limiting initial
aqueous [Pu] g/L
Extractant (M) Modifier (M)
TODGA (0.2) None <5
TODGA (0.2) HDEHP (0.5 M) 52
Chosen for process
TODGA (0.2) DMDOHEMA (0.5 M) 35
development studies
TODGA (0.2) DHOA (0.5 M) <5
TODGA (0.2) TBP <5
TODGA (0.2) 1-octanol <5
TdDDGA (0.2) None <5
TdDDGA (0.2) TBP (1.1 M) 5
TdDDGA (0.2) DMDOHEMA (0.5 M) >60 LLiigghhtt ((rreessiidduuaall)) oorrggaanniicc pphhaassee
PPuu--ccoonnttaaiinniinngg pprreecciippiittaattee
AAqquueeoouuss pphhaassee
TODGA TdDDGA
5
3rd phase boundary

60
3rd phase formed
50 no 3rd phase formed
) 40
1
-
L
g Third phase
(
g 30
r
o
]
u
P 20
[
No third phase
10
0
0 2 4 6 8
Initial [HNO ] (M)
3 aq
0.2 M TODGA + 0.5 M DMDOHEMA
Fission product behaviour
• Batch solvent extraction tests identified some fission products
are co-extracted with Ln and An.
• Fe / Sr – removed by using a low acid (0.5M HNO ) scrub.
3
• Zr / Pd – extraction
suppressed by complexation
with CDTA in the feed.
• Mo, Ru, Tc also co-extracted but difficult to scrub
from solvent
Actinide – Lanthanide separation
• Conditions optimised
for An/Ln separation
: 0.055M SO -Ph-
3
BTP / 1M AHA / 0.5M
HNO
3
Acetohydroxamic acid
2,6-bis(1,2,4-triazin-3-yl)pyridine
EURO-GANEX testing
Spiked Pu test
Solvent
Feed
Actinides
Lanthanides
Extract Extract Scrub Scrub
1 4 5 8 9 12 13 16
FPs
Active feed 0.5M HNO
3
Solvent 5 M HNO , CDTA
3
Product
Solvent
Feed
32 Ln Strip 2 29 28 An Strip 25 24 An Strip 21 20 Re-extract 17
0.1M HNO Pu, Np and
3 0.5M HNO 0.5M HNO
0.1M Glycolic acid 3 3 Am
1M AHA 1M AHA
0.02M BTP 0.1M BTP
Lanthanides
On-line analysis & Profile data
11000000
120
AAqquueeoouuss ffllooww OOrrggaanniicc ffllooww
100 880000 110000
8800
ce 80 6600 SSPP11 ffeedd ttoo ssttaaggee 2211
ass balan 60 Np] (mg/L)Np] (mg/L) 464600000000 24240000001166 1188 2200 2222 2244 2266 2288
m [[
% 40 SSPP11 ttoo ssttaaggee 2211
20 220000 AAPP11 AAPP22 AAPP33 SSRR11
0
00 HHAAFF
0 100 200 300 400
00 22 44 66 88 1100 1122 1144 1166 1188 2200 2222 2244 2266 2288 3300 3322
time (mins.) SSttaaggee nnuummbbeerr
On-line analysis Off-line analysis AAqquueeoouuss OOrrggaanniicc
4.E+04
Aqueous flow Organic flow
3.E+04
Run up to steady state (on-line Pu
L)
m
product analysis) Bq/ 2.E+04
Pu, Am, Eu profiles as expected Sr] (
[ HAF
Np accumulation and break through into AP1
1.E+04 SP1 to stage 21
HAR
Sr accumulation but directed fully to HAR 0.E+00
0 2 4 6 8 10 12 14 16
Stage number
Aqueous Organic