ISOEATC 20061012 ALARA SYMPOSIUM Introduction of the Decontamination

ISOE/ATC 2006/10/12 ALARA SYMPOSIUM Introduction of the Decontamination Method Which Uses Blasting Oct. /12/2006 IN YUZAWA JAPAN

Contents 1. Outline Decontamination 2. History of Mitsubishi decontamination technologies 3. Decontamination using blasting 4. Cavitations jet (CJ) decontamination 5. CJ + blast decontamination 6. Revolving flow polishing method 7. Summary

1. Outline Decontamination The purpose of decontamination function of subject Loss in quantity of radioactive waste Exposed reduction of a worker DF Cost Configuration of an object （structure, physical amount） Schedule （Time required） The amount of secondary wastes Area space Determination of the decontaminating method 1

2. History of Mitsubishi decontamination technologies 2

3. Decontamination using blasting facility which lifts The control panel of a whole system Blaster Accumulator Drier Compressor Cooler Drier Filter Air pressure power control panel Drum with radiation shield Outdoors Blower Blast tank Blast equipment (primary cyclones separator ) 2次ｻｲｸﾛﾝｾﾊﾟﾚｰﾀ Hose balancer Bag filter dust sampler (Vacuumed pressure) Recovery blower Supply of air ﾌ R/V ﾞ platform for shields Decontamination equipment ﾗ R/V outlet shield ｽ plug ﾄ 材 収 R/V outlet nozzle neck Vacume blast gun Blaster （Blast circulation system） 3

3. Decontamination using blasting Functional examination situation Pipe（nozzle neck mockup） 研削した跡 AIR Cylinder forcing nozzle Guide roller Nozzle （ Vacuumed blast gun） 4

3. Decontamination using blasting main specifications １． Decontamination equipment （１） Decontamination system：Dryness type vacuumed blast （３） Guide system ：Trapezoid screw sending type nozzle rotation （４）Weight：About６００ kgf／set 2．Utilities （１）Used power supply：ＡＣ２００Ｖ （２） Used air supply：Station service air ０. ６ MPa 5

3. Decontamination using blasting Features of various blasting materials alumina Aℓ 2 O 3 Glass SO 2 Iron DF large small middle large Remaining effects large middle small large small Cost large small Damage large small middle large Boric Particle Cut Wire SUS Particle Cut Wire 6

3. Decontamination using blasting l Particle diameter of the blast materials ： l l Usual φ0. 1～ 2 mm Blast pressure ： Usuaｌ l 5～ 6 kg/cm 2 Blast Angle ： Usual 45°≦ The configuration before and after activity of blast material (stainless steel grid) Case of projection factory test to steel materials Before（×２００） After 1 -time use（ × ２００） 7

3. Decontamination using blasting • • • The check of the soundness of target material When the amount of grinding is large ⇒ Reduction in thickness Loss of a resisting pressure function 8. 1～ 8. 7μm/2 times，13. 3～ 15. 1μm/3 times When the amount of grinding is locally large ⇒ SCC，Fatigue occurs Influence on the plant by remaining （Remainder of recovery， Remainder of Pierced） They are 10 cc remains at the blast of about 300ℓ 8

4. Cavitations jet (CJ) decontamination u. It compares with high-pressure water washing in mind, and is a high physical impulsive force efficiently ⇒ Compact equipment u. With no pollution expansion of dust generating etc. into air because of underwater washing u. With no influence which it has on lining in washing time of a decontamination level u. Fundamentally, with no secondary waste by decontamination Contraction Cavitation avita bubbles Liquid 9

4. Cavitations jet (CJ) decontamination Track record ① Spent fuel pit surface of wall and fuel rack cell inside Object Pit surface Purpose Before After Pollution 700～ 1200 22000 cpm removal fuel rack Dose rate cell inside reduction 5. 9 m. Sv/h 0. 9 m. Sv/h DF Note 18～ 30 ＣＪ＋ washing 6. 6 Underwater Measureme -nt data Track record② The part which has clad adhesion by contact to the fuel for a fuel extraction facility ＤＦ ２．１～１３．５（総平均８．８） 10

4. Cavitations jet (CJ) decontamination The application example to fuel extraction equipment Before (Those with blackish brown clad) After (With no adhesion remains of clad) 11

4. Cavitations jet (CJ) decontamination Enforcement example： Outline specification ØHigh-pressure pump： 16 MPa－18 L/min (Hand-pushed conveyance type) ØNozzle： 10 MPa－4. 4 L/min ØRequired utility：The power supply for pumps 220 V－23 A，Water for washing about 4ｍ3 Fuel transfer pit Pure water for work High-pressure pump Cavity Operation floor Ｃ／Ｖ Ａ／Ｂ About 6 m Lifting frame Nearly drain Floor surface washing Transfer pipe Track frame Drain part washing 2 m 長靴 Nozzle 12

5. CJ + blast decontamination ［Finishing patent application］ The polish grain mixed in the cj grinding-removes adhered clad The decontamination effect higher than what added the decontamination effect of CJ and a blast simply ◎Influence examination to in service equipment and apparatus ・In a system application test, it affection-evaluates with a mock-up The faculty of a facility is not affected even if it executes for 30 minutes ◎The faculty of a facility is not affected even if it executes 13

5. CJ + blast decontamination crane Nozzle feed device High-pressure pump 22 MPa, 15 ℓ /min P High-pressure pump feed line Filter housing Surplus water return line control panel Water recovery line Container Circulation pump ( ) Mono flex pump Blast grain suction nozzle Blast grain Turn table Frame strainer P Ｃ+ stream Ｊ SG insert plate When collecting Blast grains return line PI To air filter Air purge line フィルター Water drain line Manometer PI To floor drain 14

5. CJ + blast decontamination Applicability test with actual machine Object ： SG insert plate Before After 15

5. CJ + blast decontamination p The decontamination result in a system application test Object Ｂ-ＳＧ ＨＯＴ Ｄ-ＳＧ ＣＯＬＤ Before After 40 m. Sv/h 0. 7 m. Sv/h (14. 97 m. Sv/h) (0. 09 m. Sv/h) 25 m. Sv/h 0. 63 m. Sv/h (9. 96 m. Sv/h) (0. 09 m. Sv/h) Decontami nation time D. F. 60 min. 166 90 min. 111 Notes : ( ) inside value is the dose rate to extracted 16

6. Revolving flow polishing method ［Finishing patent application］ 〈Aim〉 Inside contamination of long piping which has a crookedness part is decontaminated A revolution style is given to a flow Blast grain In the conventional blasting, it checks that the piping crookedness part round which an Blast grain does not spread can also be decontaminated efficiently. 17

6. Revolving flow polishing method The outline of the gas revolution flow grinding method Distances the revolving flow can reach Q 1: Air to be used for revolving flow Q 2: Air to be used for suppressing revolving flow Q 3: Air to be used with abrasive Speed of abrasion Abrasive Fluidics Insertion type Revolving flow type Insert the sliding nozzle from tube end and make it move. Tube to be decontaminationed Range of decontamination is small Tube to be decontaminationed Sliding nozzle δδ (μ μm/min) Principle of generating revolving flow Butt tube ends Range of decontamination is small Distance from nozzle outlet L (m) Characteristic between speed of abrasion and distance (Long tube) Fixed nozzle 18

6. Revolving flow polishing method Average speed in piping Relation between grinding speed and the average flow velocity in piping If the average speed in piping is made quick, grinding speed will increase Speed of abrasion Element examination Flux ratio Relation between grinding speed and a flux ratio Since the flux which induces revolution speed is Q 1, if a flux ratio becomes large, degree centrifugal force will become weaker and grinding speed will become small. 19

6. Revolving flow polishing method System application examination Heart exchanger tube ① Supply air former Pressure： 0. 5 MPa ② amount of grinding airstreams ａ．For revolution style generating（Q 1）： 1200 NL/min ｂ．For revolution style control（Q 2）： 400 NL/min ｃ．For grinding material supply（Q 3）： 180 NL/min ③ Blast material： 200μm Alumina grain ④ Decontamination time ： 40分 SG Suction plug 管 板 ＊A ＊D ＊B ＊C Seal plug ＊F ＊G Oil pressure pump Channel head Oil pressure pump Preliminary recovery line Hopper Supply line Steam generator ＊E Recovery line Fluidics Vacuum cleaner Discharge side （Hot side） ＊A：For blast material supply ＊B：For revolution style generating ＊C：For revolution style control ＊D：For hopper pressurization ＊E：For vibration ＊F：For discharge part seals ＊G：For inhalation part seals Inhalation side （Cold side） Separator Steam generator heat-exchangers tube inside decontamination equipment System composition figure 20

7. Summary The needs for decontamination 【Former is also from now on】 Ø Reduction of the amount of secondary generation wastes Ø Improvement in the speed of decontamination speed ØCost reduction Ø Radiation exposure reduction The spirit of ALARA has been, and will be respected in our efforts forever. 21