Characterisation of geochemical annoyances in the Boom Clay Near Field around the PRACLAY test

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Characterisation of geochemical bothers in the Boom Clay Near Field around the PRACLAY try Waste & Disposal R&D Geological Disposal PRACLAY instrumentation day, Mol September twentieth, 2004

Overview Relevance Expected Geochemical irritations Objectives Methodology Former tests Sampling technique Originally considered inspecting positions and perusing figurings Conclusions

Relevance The Near Field (NF) geochemistry (annoyances) is viewed as Focus on the consequences for R2 (maintenance and dispersion) wellbeing capacity For the present reference idea (supercontainer), checking computations on NF geochemistry are progressing

Expected geochemical annoyances: oxidation Anoxic Boom Clay + air = oxidation (of pyrite and natural matter) 4FeS 2 + 15O 2 + 10H 2 O  4FeO(OH) + 8SO 4 2-+ 16H + Buffering limit towards fermentation, mineral disintegration/re-precipitation/cation trade Changes in maintenance and dissemination of radionuclides Porosity changes Solubility/speciation changes Sorption changes

Expected geochemical annoyances: temperature increment (HLW +) SF are in charge of Temperature increment Changes in dirt mineralogy and pore water science CO 2 generation from thermolysis of OM and changes of OM structure On-going post-doc at IFP shows arrival of CO 2 from kerogen at direct temperature increment Minerals delicate to temperature

Expected geochemical irritations: antacid tuft Caused by the utilization of solid/bond Experimental set-up not really identified with PRACLAY exhibition and along these lines excluded amid the PRACLAY explore During destroying, this theme will be incorporated Samples will be taken at the interface concrete - mud

Objectives of Research Plan irritations watch and comprehend the wonders of geochemical annoyances gauge the degree of the synthetic bothers Next stage assess the impact on the R2 (dissemination and maintenance) security capacity of the host shake make proposals to execution evaluation and R&D on the best way to consider the impact of geochemical irritations. The idea utilized ought to be at any rate moderate

Former test: CERBERUS Evolution of pore water science was watched No noteworthy impacts on mineralogy could be watched No huge consequences for kerogen could be watched

What to quantify Pore water is relied upon to respond quick on oxidation and temperature increment On-line estimations or continuous compound examinations Mineralogical changes are just slight inside the temperature/time scope of the PRACLAY test Limited measure of tests Additional inspecting at destroying of the Praclay analyze

Sampling system Before the removal of the PRACLAY display Drilling and coring at the position of the channels with least unsettling influence (dodge oxidation however much as could be expected) Installation of multi-channel piezometers During the PRACLAY test No penetrating/coring Frequent follow-up of pore water science without aggravating weight estimations Sampling for the geochemical study may never bother the THM estimations (significant objective of the venture)

Sampling technique Heating of tubes and lodge to keep up consistent temperature Gas-stage (CO 2 ) examining level Sample circle: Routine water investigations Eh - pH

Originally considered examining positions 10 m 15 m 15 m View from above Hydraulic attachment Side view

Scoping counts of CO 2 generation 5 Observation hubs 2 4 1 3

Temperature profiles expected at hubs

Simulated CO 2 creation (mg CO 2/g kerogen) 1 flat 5 2 4 even 3 1 3 4 5 slanted

Simulated CO 2 creation Important CO 2 creation in the initial 6 months insufficient test information? Identified with glimmer discharge amid pyrolysis? Most likely better displayed after long haul explore Continuous CO 2 creation increment in flat piezometer Limited distinction in channels of slanted piezometer and scarcely any expansion following 6 months 6 months

Simulated CO 2 fixation in Boom Clay pore water 1 Assumptions 3% OM Of which 80% kerogen All CO 2 broke down in pore water 2 3 4 5 Reference HCO 3 - foundation 5 2 4 3 1

Newly proposed inspecting positions 10 m 15 m 15 m View from above Hydraulic fitting Side view

Conclusions Set-up ought to permit a follow-up of geochemical irritations CO 2 generation anticipated that would be generous CO 2 increment ought to be quantifiable around PRACLAY warmer test Optimization of channel position is required