Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Basic Water plan for Hyper-Kamiokande -Water system & water flow- Open Meeting for Hyper-K Project Aug Hiroyuki Sekiya ICRR, University of Tokyo for the Hyper-K Working Group

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Basic idea Base design is Super-Kamiokande ◦In order to study same/beyond physics achieved by Super-K, water quality in Hyper-K must be same as /better than that in Super-K. ◦We know Super-K water works quite well as 50kton target material with 60t/h recirculation flow rate and the water purification technology is well matured. For 1Mton target, the purification flow rate should be more then 1200t/h. ◦It’s quite huge and it is not trivial. The feasibility must be checked. 2

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Purpose of this session Feasibility check of “1Mt ultrapure water Cherenkov detector” ◦Mine water survey. ◦1200t/h water purification system design. ◦Keeping 1Mt ultrapure water in the tank. (This is the challenge!) 3 50kt tank 60t/h flow → 14Mcm 800t tank 5t/h flow → 17.7Mcm

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Purpose of this session Explore “functional water” ◦Adding some materials into water could enhance Hyper-K physics potential. Gd Option (Mark Vagins) Liq. Scintillator Option (David Jaffe) ◦However, these require additional technical studies.  Ex) reaction with detector material, concentration uniformity, purification method, keeping quality in 1Mt tank ◦These technology might be applied to near detectors. 4

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Ultrapure water Cherenkov detector 5

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Mine water survey At Mozumi cite, we have information and experience. We surveyed Tochibora cite water 6 HyperK SuperK 2700mwe 1750mwe

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Tochibora Mt. Nijugo( 二十五山 )

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa 30m シックナー 鉛リサイクル工場 硫酸工場 亜鉛製錬工場金属粉工場 下部清水 上部清水 鹿間発電 第三ポンド 栃洞鉱山 ３００ｔ 水槽 ５０ｔ水 槽 １５０・１６０・１７０ KW ポンプ 総合調整池 硫酸３０ｔ水槽 孫右衛門 ０ｍポン ド ２８，４２０㎥ /day 3,456 ㎥ /day t/day 5687 t/day 繰り返しポンプ 工業用水（１２月平均デー ター） 硫酸２００水槽 下部濁水 ９,000 ㎥ //day （推測） -430m -370m 水温 ７．５℃ 水温 １０．３℃（山側） 水温 ８．２℃（川 側） ＊ 排水処理設備は省 略 8346 t/day ＊ 季節変動有 984 ㎥ //day 底設暗渠清水 Total spring in Tochibora mine is 540t/h and all the water is used for the smelting factory During the initial supplying, we have to ask to let us use (i.e. stop their operation). The problem: Shortage of mine water

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Quality of Mine water

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Mine water quality Almost same as Mozumi mine water : pretreatment is not necessary like SK system. MozumiTochibora

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Super-K water system

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Matured technology 12 Filtrations & Deionization (General technology) Radon Degasifying (Super-K technology) ◦Radon free air generator ◦Radon removal with membrane degasifier MF UFUF NFNF RO DI UV sterilization (General technology)

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Hyper-K water system 13

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa CompressorDryer 0.3  m filter Buffer H 2 O,CO 2 remover 20 o C Charcoal 0.1  m filter 0.01  m filter 0.01  m filter -40 o C Charcoal Buffer 10  m filter Buffer CO2 remover Buffer 1  m filter HK Tank Rn Free Air generator (400Nm 3 /h) Water Purification System 0.3kt/h for initial supply Mine water RO DI(MB) DI(CP) UV MD UF T controller 1.2kt/h for recirculation purge

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Mine water consumption 24h x 407t/h /day Pure water 300t/h It takes 70 days for filling one tank. 140 days for 1M ton Filling mode 1 st stage is common for both tank 2 nd stage for each tank. Does not work at the same time

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Mine water Consumption 2h x 28t/h /day 600t/h It takes 35 day to process 1Mton water Recirculation mode 1 st stage is used for UF reject water and compensation water RO reject 56t/h No RO in the recirculation system RO requires high pressure pumps high running cost large space

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa 58m 13m ＜ 1 次純水装置・ラドンレス 空気製造装置エリア＞ 1 st stage layout ●58mL×13mW 断面： 13mW×13mH

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa 32m 11m 12m 11m ＜サブシステムエリア＞ 2 nd stage layout ●32mL×11mW 断面： 11mW×12mH このエリアが２つ 必要となります。

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Including ◦400Nm 3 /h Rn Free Air generator ◦Man power and cost for initial filling 30 Oku-Yen Estimated Cost

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Keeping water quality in huge tanks with limited flow 20

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Super-K water transparency 21 anti-correlated with Supply water Cherenkov light wavelength Measured by decay e - e + from cosmic  -  + SK-IV SK-III Started automatic temperature control

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Convection suppression in SK Very precisely temperature-controlled (±0.01 o C) water is supplied to the bottom MeV-4.5MeV Event distribution Return to Water system Purified Water supply r2r2 Temperature gradation in Z The difference is only 0.2 o C

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa ID bottom OD bottom OD top ID,OD top 12t/h 36t/h 60t/h Ver.14May 2012 Current SK situation Stagnation and top-bottom asymmetry. Emanated (from PMT/ FRP) and accumulated Radon Bacteria in low flow rate region

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Well-balanced operation in SK 1 st priority for lowE ◦low BG (BG) ≡ stagnation 1 st priority for atmpd/T2K ◦small systematic errors ≡ uniformity ≡ convection A 6%-level top-bottom asymmetry of water transparency exists, however the systematic error on the SK energy scale due to this is below 0.1%-level after correction*. The operation strategy is determined by physics motivations * see calibration session

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa For bacteria free and uniform (High-E oriented) Hyper-K O 3 or UV sterilizer in the tank is not good for PE surface. PE may get damaged and emit particles. So far, continues high speed flow is the only solution to suppress bacteria in the tank. To make the most of the “1200t/h flow rate”, water flow design in the HK tank is underway.

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Water Flow design by finite volume method One compartment for the first step Software: ANSYS GAMBIT2.4.1+Fluent13.0

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Water inlets & outlets condition Equally distributed per top/bottom cross section ◦Will be optimized through this analysis for “EGG shape tanks” SK type Top outlets ID OD Base concept: Supply to bottom and drain from top

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa ID & OD Conditions ID & OD are dealt as completely separated containers. 28 Inner detectorOuter detector Volume370,000m 3 89,000m 3 Flow rate96.7t/h23.3t/h Number of inlets (outlets)184 Flow rate / inlet (outlet) Because of its symmetrical shape, only 1/4 volume is considered for the simulation. 1,400,000 mesh (xy, and yz symmetry)

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Rock and mine water on May Cooling water o C -300M (Top level) rock 16.7 o C Here Boring hole Measured 1m inside Almost same as those in Mozumi/SK →assuming supplying 13.0 o C water

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa on May Boring No2 Boring No3 Boring No4 -370M(bottom level) rock No o C No o C No o C Boring No3 Average (17.7 o C) is close to the nearest No3 value. assuming 17.7 o C Depends on position and the variation is large.

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Other heat source estimation Unlike SK, electronics(HV, QBee,..) are also in the tank. The heat from compensation coil depends on the direction of the tank. 47.4kW Area For one compartment

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Preliminary results ID: fast flow (much faster than 1 day) ~convection OD : half like Super-K 32 ID flow OD flow

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Water replacement efficiency 10 days after starting recirculation 33 Color scale[0:1] Initial old water: blue The ratio of new water 0.3

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Water replacement efficiency 20 days after starting recirculation 34 Color scale[0:1] Initial old water: blue The ratio of new water 0.5

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Water replacement efficiency 30 days after starting recirculation 35 Color scale[0:1] Initial old water: blue The ratio of new water 0.7 In ID, uniformly replaced, but the efficiency is not good due to the stir.

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Conclusion Tochibora mine water quality was surveyed. Based on this result and Super-K system, Hyper-K water supply and purification system was designed. Water flow design in the tanks depends on our physics motivation. ◦So far, a water flow tuned for high-E physics is being designed. ◦LowE-tuned water flow will be designed in the case of Mozumi Hyper-K. ◦Can we develop a flow-control system? 36

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Water replacement efficiency 10 days 37 Color scale[0.25:0.3]

Hiroyuki Sekiya Open Hyper-K meeting Aug 23 Kashiwa Water temperature in the tank Color scale [286K:287K] 38