T 2 K water drainage exhaust air Yuichi

Future Improvements for higher beam power T. Koseki in　NBI 2014 l If the budget

Overview l Although some improvements are still needed, present water drainage procedure and air

Cooling water systems in T 2 K neutrino beam line 3 independent cooling water

Disposal Scenario of Radioactive Cooling Water in the Target Station 1 month n beam

Summary and Prospect for Radioactive Water Drainage FY 2012 FY 2013 FY 201 X

7 Be l 7 Be and other metal radio-nuclei can be removed by ion-exchangers.

Y. O NB yama I 20 12 After ~5 years from the commissioning, the

Number of Drainages l In the present drainages, we can dispose: 84 m 3

Tank Truck l The back-end section of JAEA provides a service to take over

A New Building l The drainage of the radioactive water is definitely limited by

New Buildings in the neutrino beam-line RCS Near Neutrino Detectors Muon Monitors Beam Dump

Total 3 H problem l We have assumed that the disposal quota of 3

Summary : Water Drainage l We will be ready for 750 k. W x

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Radiation in exhaust air : Summary in NBI 2012 by T. Ishida l Radiation

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Summary : Exhausted Air l Careful air-tightening, including use of air-tight lamination in the

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T 2 K water drainage / exhaust air Yuichi Oyama (KEK) Sep-25 -2014 NBI [email protected]

Future Improvements for higher beam power T. Koseki in　NBI 2014 l If the budget is funded timely, 750 k. W beam will be delivered in JFY 2017. l Upgrade plans of accelerators after 750 k. W are still under discussion.

Overview l Although some improvements are still needed, present water drainage procedure and air exhaust system are possible to accept ~750 k. W beam power. l See talks in NBI 2012 workshop. http: //indico. cern. ch/event/193710/session/14/contribution/56 for water drainage talk by Y. Oyama, and http: //indico. cern. ch/event/193710/session/14/contribution/57 for exhaust air talk by T. Ishida. l In this talk, progress in recent 2 years are reported. Future upgrade plans aiming at ~2 MW beam operation are also presented.

Water Drainage

Cooling water systems in T 2 K neutrino beam line 3 independent cooling water systems. TS cooling water system （TS and DV upstream, 7. 8 m 3） BD cooling water system （DV downstream and BD, 10. 0 m 3） Horn cooling water system (2. 7 m 3) l Horn and TS cooling water are disposed from facilities in an upstream building (NU 2), and BD cooling water are disposed from downstream NU 3 building. l Products from Oxygen except 3 H and 7 Be decay within several ten minutes, or have extremely long life. Disposal scenario of only 3 H (t 1/2=12. 3 y) and 7 Be (t 1/2=53. 3 d) must be considered. l Metal ions from beam-line components/pipes are resolved in water. 22 Na (t 1/2=2. 6 y), from Aluminum must be considered.

Disposal Scenario of Radioactive Cooling Water in the Target Station 1 month n beam Target Station (off-limits) From 2013 maintenance Ion exchangers clean water TS/DV cooling water system (7. 8 m 3) clean water Until 7 Be removed a~satisfactory few days 10 days B 2 tank (~4 m 3) Na. OH 2011 Buffer tank ~80% 3 days/cycle clean water p. H control system H 2 SO 4 Horn cooling water system (2. 7 m 3) n beam p. H~7 p. H<4 2 Dilution tanks (42 m 3 x 2) drainage (19. 5 m 3) Ion exchangers Drain 2012 tank w (20. 5 m 3) drain water from air-conditioner etc

Summary and Prospect for Radioactive Water Drainage FY 2012 FY 2013 FY 201 X FY 202 X? Beam power 3. 10 x 1020 pot (=149 k. W x 107 s eqv. ) 2. 20 x 1020 pot (=106 k. W x 107 sec eqv. ) 15. 6 x 1020 pot (=750 k. W x 107 s eqv. ) 41. 6 x 1020 pot (=2 MW x 107 s eqv. ) 7 Be ~180 GBq 36. 5 MBq (by ion-exchangers) Reduction rate 99. 98% ~130 GBq 6. 5 MBq (by ion-exchangers) reduction rate > 99. 99% ~920 GBq 46 MBq (by ion exchangers) ~2500 GBq 120 MBq (by ion exchangers) *the same reduction rate as FY 2013 is assumed 77. 6 GBq (NU 2) 30. 0 GBq(Horn) 47. 6 GBq(TS) 15. 9 GBq (NU 3, BD) --------------93. 5 GBq (NU 2+NU 3) 57. 3 GBq (NU 2) 22. 1 GBq(Horn) 35. 2 GBq(TS) 15. 1 GBq (NU 3, BD) ---------------73. 2 GBq (NU 2+NU 3) 390 GBq (NU 2) 151 GBq(Horn) 239 GBq(TS) 95 GBq (NU 3, BD) ---------------485 GBq (NU 2+NU 3) 1040 GBq (NU 2) 403 GBq(Horn) 637 GBq(TS) 253 GBq (NU 3, BD) ---------------1293 GBq (NU 2+NU 3) 27 times x 84 m 3 (NU 2) and 25 times x 17 m 3 (NU 3) 17 times x 84 m 3 + 3 times x 42 m 3 (NU 2) and 23 times x 17 m 3 (NU 3) ~70 times x 84 m 3 (NU 2) a few x 17 m 3 (NU 3) and 12 times x ~24 GBq (Tank Truck) > 100 times x ~100 m 3 (NU 5) and Tank Truck (Total) < 1200 MBq per year 3 H (Total) < 800 GBq per year (Concent. ) < 60 Bq/cc (< 42 Bq/cc for safety) Drainage and Disposal

7 Be l 7 Be and other metal radio-nuclei can be removed by ion-exchangers. We need long circulation time to remove 7 Be. l For example, the volume of the buffer tank is ~20 m 3, and the flow rate in the ion-exchangers is ~1 m 3/hour. After 1 day circulation, the concentration of the radioisotopes will become only ~1/e. l From 2013, the horn cooling water is circulated in the ionexchangers in the target station even during the beam period. l This improved the reduction rate drastically. In 2013, total 7 Be in the drain water is only 6. 5 MBq, where the limit is 1200 MBq. This reduction rate is satisfactory even if the beam power is upgraded to be ~2 MW. l Remaining problems are the lifetime and replacement of the ion-exchangers.

Y. O NB yama I 20 12

Y. O NB yama I 20 12 After ~5 years from the commissioning, the ion-exchangers are still alive. The lifetime of the ion-exchangers is longer than that of 22 Na !

Number of Drainages l In the present drainages, we can dispose: 84 m 3 x 42 Bq/cc = 3. 53 GBq in NU 2 17 m 3 x 42 Bq/cc = 0. 71 GBq in NU 3 In FY 2012, 149 k. Wx 107 s beam and 27(NU 2)+25(NU 3) drainages. For 750 k. Wx 107 s beam, 110(NU 2)+130(NU 3) drainages are needed. l Present number of drainages are limited by: - one drainage needs 3 days for dilution, radiation measurements and drainage. Maximum number of drainages is twice per week. - Work only on business days. l If facility upgrades are not assumed, the possible solutions are upgrade of the manpower. -Shorten the drainage cycle, and no weekly limit? -Work on…… ……Saturdays, …Sundays, ……. National holidays…. . Accepting 750 k. W beam is not realistic !

Tank Truck l The back-end section of JAEA provides a service to take over radioactive water by a tank truck. They can dispose them in another facility. They can take over 8 m 3 x ~3000 Bq/cc 3 H by their tank truck at a time. It corresponds to ~24 GBq 3 H. The maximum frequency of the service is once a month. l Because of the small disposal tanks in NU 3, use of the tank truck service in NU 3 is more effective. One tank truck can reduce more than 30 times of drainages in NU 3. l The first takeover by the tank truck in NU 3 is planned in early next year. We may be able to negotiate about the frequency after that. l About 70 drainages from NU 2, a few drainages from NU 3, and 12 tank truck takeovers in a year is realistic for 750 k. W beam.

A New Building l The drainage of the radioactive water is definitely limited by the capacities of the disposal tanks, 84 m 3 in NU 2 and 17 m 3 in NU 3. l We are planning to build new facility buildings, namely NU 4 and NU 5, for new cooling water system, new disposal tanks and other facilities. l In the primary conceptual design, we will build 6 disposal tanks, 50 m 3 volume each in NU 5. Blank space around the neutrino beam-line is strictly limited, and this is the maximum number/volume. l Since we can also use old disposal tanks in NU 2, the total volume of the drainage will be improved by factor ~4. l We will need ~2 years for construction, and full 1 -year shutdown for the construction.

New Buildings in the neutrino beam-line RCS Near Neutrino Detectors Muon Monitors Beam Dump m 110 m 280 m MLF 18 NU 5 NU 4 P P Be rima am ry -li ne Extraction Point ng Ri 295 km To Kamioka p Target & Horns in Target Station n ai M n Decay Volume

Total 3 H problem l We have assumed that the disposal quota of 3 H, 800 GBq/year, means that we can dispose 3 H within this limit without any special care. The total quota in J-PARC is 5000 GBq/year. For ~2 MW beam, we expected to borrow additional quota from other facilities. l However, it was pointed out that the local government and Tokai residents must agree with the drainage even if the 3 H is less than the quota. Specially, the local government addresses that why only neutrino facility must dispose such amount of 3 H. The total 3 H from MLF (Materials and Life Science Experimental Facility) is 1. 2 GBq in FY 2013, much less than the neutrino facility. l Persuasive explanation and tough negotiation will be needed. We will encourage MLF people to dispose much more radioactive water.

Exhaust Air

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Radiation in exhaust air : Summary in NBI 2012 by T. Ishida l Radiation in exhausted air has been reduced by air-tightening and bypass line of the ventilation. l 0. 1 m. Bq/cc at 190 k. W has been succeeded.

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Summary : Exhausted Air l Careful air-tightening, including use of air-tight lamination in the future, will reduce the leakage of radiation from the underground area. l In the bypass of ventilation, further change of the bypass rate will be needed for higher beam power.

Summary : Water Drainage l We will be ready for 750 k. W x 107 sec beam by the tank truck and more frequent drainages. l For ~2 MW beam operation, more disposal tanks are needed. l The total 3 H is another serious problem. Summary : Exhausted Air l Careful air-tightening, including use of air-tight lamination in the future, will reduce the leakage of radiation from the underground area. l In the bypass of ventilation, further change of the bypass rate will be needed for higher beam power.

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