hiroyuki sekiya june 3-9 2012, kyoto, neutrino2012 design of a huge water purification system based...
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Hiroyuki Sekiya June 3-9 2012, Kyoto, NEUTRINO2012
Design of a huge water purification system based on the Super-Kamionade system
Hiroyuki Sekiya* for the Hyper-Kamiokande Working Group*Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo
Preface: Hyper-Kamiokande (Hyper-K) will be a detector capable of observing CP violation in the Lepton sector, proton decays, atmospheric neutrinos, solar neutrinos, both supernova burst neutrinos and supernova relic neutrinos, and dark matter with sensitivity far that of the Super-Kamioknade(Super-K) detector. Water is the target and signal-sensitive medium of the detector, and thus its quality directly affects the detector’s sensitivity. For that reason, water purification is critical to realizing such a huge water Cherenkov detector.
SKSK
1.Hyper-K detector vessel
2. Super-K water system as base design
Technical terms / abbreviation
3. Hyper-K water system will process 1.2kt/h
Although it takes 35 days to replace the water in the 50kt SK tank, its water transparency is always kept above 100m. Backgrounds are low enough to detect >3.5MeV solar neutrinos. A 5%-level top-bottom asymmetry exists, however the systematic error on the SK energy scale due to this is below 0.1%-level after correction.
39.3m
41.4m
2 cylindrical tanks lying side-by-side (48m x 54m x 250m each)5 compartments in each tank
Total volume 0.99 MtFiducial vol. 0.56Mt Total volume 0.05 Mt
Fiducial vol. 0.0225Mt
reject (drain)
reject (drain)
mine water
drain
reject
Primary pump
filter
filter
RO-1 pump
RO-2pump
RO water tankpost RO
pump
RO-2
RO-1-1
vacuum degasifier
RO-3
reject
RO-3 pump
Ion exchanger 1/2
UVsterilizer
purified water supply pump A/B
A
BUltrafiltrationmembrane
membrane degasifier
reject
550
Rn-free-air dissolving tank
strainer
FP-4 FP-5
RT-3
RT-4RT-2
RT-1
CV-1
IDbottom
CV-2
v94
700
compensation pump strainer
UF reject tank
HE1
rejectHE3 reject UF reject pump
Main return pump A/B
HE4
RO-1-2
Super-Kamiokande IV water system since Feb. 2012
Recirculation rate: 60t/h
Reverse osmosis (RO) membrane Filters out ions, contaminants larger than 0.1nm, bacteria etc.
(Mixed-Bed) Ion exchanger Uses resin to remove ions such as calcium and uranium
Cartridge Polisher(CP) Highly pure ion exchange resins remove all ions from water
UV sterilizer(UV) Bacteria sterilization using ultraviolet rays
Vacuum degasifier(VD), Membrane degasifier(MD) Removes gases such as Oxygen and Radon
Ultrafiltration(UF) membrane Removes nanometer-sized particles
Super-K water quality
Takes 70 days to fill one cylindrical tank. Takes 35 days to replace the water in the both 0.5Mt tanks.
3.5MeV-4.5MeVEvent distribution
Return toWater system
PurifiedWater supply
Maintaining operation is the first priority
To avoid convection, very precisely temperature-controlled (±0.01oC) water is supplied to the bottom. Rn Free Air (Rn is removed down to mBq/m3 level by charcoal ) is used for purging.
5 compartments for each tank Water will be recirculated independently in each compartment at 120t/h. The effects of the egg-shape cross section
on the water flow will be taken into account when designing the inlet/outlet.
Rn Free Air generator (400Nm3/h)
Water Purification System
Compressors Air dryer0.3mmfilter Buffer tank
CO2 H2O remover Charcoal
0.1mmfilter
0.01mmfilter
0.01mmfilter Buffer
-40oCCharcoal
purge purge purge
purge purge purge
0.3kt/h for initial supply
0.6kt/h for recirculation
0.6kt/h for recirculation
Mine air
Mine water
Buffer tank
Buffer tank
10mm filter Buffer Reverse Osmosis
membraneCO2
remover
Mixed-BedIon exchange resin
Cartridge PolisherIon exchange resin
UVsterilizer
Membrane degasifier
1mm filter
Chillerw/ T control
1mm filter
UVsterilizer
Cartridge PolisherIon exchange resin
Ultra-filtrationmembrane
Chillerw/ Temp control
UF reject
Ultra-filtrationmembrane
Membrane degasifier
HK tank
HK tank
r2
Ion Molecule Macromolecule Macro “particles”
Reverse osmosis
0.001 0.01 0.1 1 10 100 1000
Ion exchange
Nanofiltration
Ultrafiltration
Microfiltration
Usual filtration
Precipitation
Size mm
x 20
UVsterilizer
Cartridge PolisherIon exchange resin
Reverse Osmosis membrane
Reverse Osmosismembrane
Ultra-filtrationmembrane
Membrane degasifier
Reverse Osmosis membrane
Chillerw/ Temperature control
Vacuum degasifier
Chillerw/ Temperature
control
Chiller
Mine water
Initial supply rate: 30t/h
SK tank
Super-K IV lowest energy eventssolar angle distribution
Super-K IV Water transparency
anti-correlated with Supply water temperature
@ Cherenkov light wavelengthMeasured by decay e-e+ from cosmic m-m+
Water quality control
Water flow studies are underway
Inner detector Outer detector
Volume 370,000m3 89,000m3
Flow rate 96.7t/h 23.3t/h
Number of inlets (outlets) 18 4
Flow rate/inlet (outlet) 5.37 5.82
Inlet (outlet) configuration on the top and bottom sections
A “bad” example Finite volume methodANSYS GAMBIT2.4.1+Fluent13.0
¼ Inner detectorStagnation@center?
¼ Outer detectorDownward flow?
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