Methodology of hydrochemical study

1. Methodology of hydrochemical study

2. MIU site Regional area • Sampling and analysis of surface water (rain water, river water, soil water) • Borehole investigations • Batch bottle and/or pump up sampling • Quality control on drill fluids contamination • In-situ measurement of pH, Eh

3. Down-hole chemical probe unit (made by JAEA) • Advantage • Enable to water sampling in inert and pressurized condition • Minimum degassing • In-situ pH, Eh measurement • Disadvantage • -Require the long time to pump out drill fluids Control unit Casing pipe Pumping cable Pump unit Measurement unit Sampling unit Docking unit Guide unit Upper packer Filter Sampling interval Lower packer

4. Probe Packer Sampling port Sampling bottle Probe and bottle Groundwater MP system (made by Schlumberger co.) • Advantage • Enable to water sampling at inert and pressurized condition • Multiple water sampling intervals • Minimum degassing • Long-term monitoring • Disadvantage • -Require the time to install the system • -Contamination of drill fluids occurs into sampling interval before system install

5. Water sampling during hydraulic test (combination of conventional methods) Chemical monitoring system • Advantage • -Easy to pump out the drill fluids • Concurrent research on hydraulic parameter and water sampling • Disadvantage • impossible to measure the in-situ pH, Eh • Degassing occurs Flow regulation valve 3 inch casing Pump Casing Control light cable Control unit measurement unit Pump unit Upper packer Packer unit Lower packer

6. Quality control to remove drilling fluids - Planning of drilling and GW sampling - Selection of drill fluid and tracer Planning • - Addition of tracer • Control the tracer concentration in drill fluid returned • Continuous monitoring of physico-chemical parameters • Analysis of chemistry Drill the borehole GW sampling • Continuous analysis of tracer concentration in sampled GW • After tracer decreasing, GW sampling

7. How to compile the data and check the quality

8. Selection of tracer and control the concentration • Note • Intensity of fluorescence in concentration used • Relation between fluorescence and pH of water • Property for rock minerals • Influence for other tracer materials Uranine Eosin Sodium-naphthionate Amino G. acid Control the concentration in drill fluid: within +/- 10%

9. How to control the quality of groundwater samples ? Drilling fluid + Tracer GW Immediately after drilling GW is sampled after tracer concentration below a few %. Pump up drilling fluid and GW GW sampling

10. To good quality measurement on pH, Eh Difference of measurement values by various methods - Batch bottle sampling and measurement - Pump out sampling and measurement - In situ monitoring Pump out water: pH value possibly changes by degassing of carbon dioxide. Eh value measured at ground surface possibly changes by degassing such as H2S. In situ monitoring Flow cell electrode at surface (Pt) 400 Flow cell electrode at surface (Au) 200 Eh [mV] 0 -200 0 5000 10000 15000 Pump out [L]

11. .2 Fe(OH)3(am) .1 H2CO3(aq) HCO3- 0 CO32- HCO3- Fe2+ -.1 Eh (volts) SO42- -.2 FeOH+ Fe(OH)3- -.3 H2S(aq) HS- o Pyrite -.4 25 C 4 5 6 7 8 9 10 11 pH 200 0 Akeyo, Hongo F. Toki lignite-bearing F. Granite (grey square are DH-2 samples) Previous Eh data of CH4, H2S-free granitic groundwater -200 -400 -600 -800 -400 -200 100 0 To good quality measurement on pH, Eh Measured at ground surface Measured at in-situ point Eh values measured at ground surface show oxidized values compared with in-situ measurement values.

12. N MSB-4 MIU construction site MIZ-1 MSB-2 Shafts DH-15 DH-2 Sampling locations Around MIU construction site Borehole length and inclination（from vertical） ・MSB-2：180m，0° ・MSB-4：99m，0° ・MIZ-1：1300m，0°～14° ・DH-2：501m，0° ・DH-15：1012m，0° 46 samples from 5 boreholes

13. Monitoring system in boreholes Water pressure gauge Pump Packer Packer line Stand pipe Measurement port Packer Main shaft Pumping port Ventilation shaft Valve packer Valve packer line Water pressure Measurement port Water chemistry End plug Piezometric system MP system DH-15: approx. 500m far from east side of shafts Continuous monitoring of water pressure at 8 boreholes (72 intervals)

14. In the shafts and galleries Monitoring system Monitoring of hydrochemical disturbance at drifts Hold Multi-interval packer system Packer Packer Packer Packer Monitoring point Monitoring point Monitoring point Monitoring point Monitoring point Water • Continuous monitoring of water pressure and chemistry at boreholes • Observation of inflow rate and chemistry at water collection rings (20 points in each shaft) Water collection ring （40points）

15. Hydrochemicalmonitoring system in gallery • Advantage • -Drill fluids is spontaneously removed during drilling • Artesian water sampling at inert/pressurized condition • Multiple water sampling intervals • Minimum degassing • Long-term monitoring Gallery sampling unit deta collection unit measuring unit Sampling intervals isolated packers in borehole

16. Around Closure test drift Water pressure and chemistry (32 points) 12MI33, 13MI38: ～ 13MI39-41: ～ 13MI45-48:For each one section In the drift: ～ Rock strain (12 points) 13MI42：　　　～ 13MI43：　　　～ 13MI44：　　　～ 1 6 1 1 1 4 2 2 13MI41 1 1 4 3 3 4 4 13MI44 13MI45-48 2 4 9 1 12 8 3 5 11 1 3 10 3 2 4 3 4 7 12MI33 2 6 4 3 1 12 8 5 4 13MI40 6 7 2 5 1 13MI43 1 cement 13MI39 2 6 3 13MI38 13MI42 cement Monitoring boreholes Impervious plug and penetrating water monitoring tubes Water monitoring tubes connecting boreholes and monitoring equipment via plug Hydrochemical monitoring equipment 15

17. Observation to get snap shots in time Addition to above, noble gas, 14C, 36Cl samples are also collected properly for precise study.