Disposal of radioactive waste

The radioactive wastes retain their radioactivity and emit radiations which are harmful for the environment and its occupants. So they are to be handled and disposed carefully(i.e) isolating it from the environment.

1. DISPOSAL OF RADIOACTIVE WASTE VADIVELAN 2013111107 SIDHAARTH 2013111118 SAI KRISHNA 2013111122

2. NUCLEAR WASTE Composed of Radionuclides Low, Medium and High level wastes High level wastes produced in nuclear reactors consists of Fission products(short-half lives) Actinides(long-half lives)

3. CLASSIFICATIONS Nuclear waste is segregated into following classifications Low level waste which is not dangerous but sometimes requires shielding during handling. Intermediate waste typically is chemical sludge and other products from reactors. High level waste consists of fissionable elements from reactor core. Transuranic waste is any waste with transuranic alpha emitting radionuclides whose half-life is longer than 20 years.

4. WASTE VOLUME

5. LOW LEVEL WASTE (LLW) Contains VERY LOW concentration of radioactivity. Waste which does not require shielding during normal handling and transportation. 90% volume of waste.

6. INTERMEDIATE LEVEL WASTE (ILW) Intermediate level waste contains higher radioactivity levels than low level wastes. Waste which requires shielding but needs little or no provision for heat dissipation during its handling and transportation. Intermediate level waste typically is chemical sludge, resins etc. 7% volume of the waste.

7. HIGH LEVEL WASTE (HLW) High level waste has a large amount of radioactive activity and is thermally hot. 3% volume of waste. 95% of radioactivity. Current levels of HLW are increasing at about 12,000 metric tons per year. Most HLW consists of Pu-238, 239, 240, 241, 242, Np-237, U-236.

8. BASIC STEPS AND ACTIVITIES IN RADIOACTIVE WASTE MANAGEMENT Waste generation occurs during the operational period. It can be in the form of solid, liquid or gaseous waste. Pretreatment is the initial step that occurs just after generation. It consists of collection, segregation, chemical adjustment and decontamination. Treatment involves changing the characteristics of the waste. Basic treatment concepts are volume reduction, radionuclide removal and change of composition. Conditioning involves those operations that transform radioactive waste into a form suitable for handling, transportation, storage and handling. Storage facilities maybe co-located with a nuclear power plant or licensed disposal facility. Retrieval involves the recovery of waste packages from storages either for inspection purpose or further storage in a disposal facility. Disposal consists of the authorized emplacement of packages of radioactive waste in a disposal facility.

9. DISPOSAL OF LOW LEVEL WASTE NEAR SURFACE DISPOSAL: Disposal in a facility consisting of engineered channels or vaults constructed on the ground surface or up to few tens of meters below ground level . These type of wastes loses most or all of its radioactivity within 300 years. It includes contaminated equipment from the operation of nuclear power plant like clothing, rags, tools and equipment. Very short-lived low-level radioactive waste such as that from hospitals, universities and industry generally contains only small amounts of radioactive materials with short half-lives. This means that radioactivity decays away in hours or days.

10. DISPOSAL OF LOW LEVEL WASTE

11. DISPOSAL OF INTERMEDIATE LEVEL WASTE Depending on its characteristics, intermediate level radioactive wastes can be disposed in facilities of different types. Disposal could be by emplacement in a facility constructed in caves, vaults or silos at least few hundred meters below the ground level. Intermediate level radioactive wastes require long-term management. These are much bulkier materials and are first sealed in steel drums and are encased in concrete trenches.

12. DISPOSAL OF INTERMEDIATE LEVEL WASTE

13. DISPOSAL OF HIGH LEVEL WASTE GEOLOGICAL DISPOSAL: A deep geological repository is a nuclear waste repository excavated deep within a stable geologic environment. Most long-lived radioactive wastes are stored here. The volume of these HLW can be reduced by Nuclear reprocessing. This reprocessing does not eliminate the need for a repository, but reduces the volume. These repositories are at least a few hundred meters below the ground level.

14. DISPOSAL OF HIGH LEVEL WASTE

15. DEEP BOREHOLES Deep borehole disposal  is the concept of disposing high-level radioactive waste  from  nuclear reactors  in extremely deep  boreholes  instead of in more traditional  deep geological repositories  that are excavated like mines. Similar concept to geological repositories. Kilometers deep rather then hundreds of meters. Provide further insulation from ground water.

16. DEEP BOREHOLES

17. LAUNCH INTO SPACE Near infinite storage space. Completely removes waste from biosphere. High technical risks and problem of space vehicle failure. High energy cost of space launch. The current cost to launch an object into orbit around the earth is about $20,000 per kilogram.

18. LAUNCH INTO SPACE

19. THANK YOU