Nuclear Waste…Why?Nuclear Waste…Why?•Recently nuclear power has entered many discussions as world energy needs rise and oil reserves diminish. •Most opponents of nuclear power point to two main arguments: meltdowns and nuclear waste.•Nuclear waste is any form of byproduct or end product that releases radioactivity.•How to safely dispose of nuclear waste is pivotal for the continued operation of nuclear power plants, safety of people living around dump sites, and prevention of proliferation of nuclear materials to non-nuclear states

Nuclear Fuel Cycle

Most nuclear waste comes from the byproducts of the nuclear fuel cycle. The cycle typically is split into three sections: front end, service period, and back end. There can be intermediate stages that include the reprocessing of nuclear waste elements.

Nuclear Fuel Cycle (Cont.)Nuclear Fuel Cycle (Cont.)

•  Nuclear Waste  enters the body through the lungs where it is known to cause cancer. 

• It mimics iron in the body, migrating to bones, where it can induce bone cancer or leukaemia, and to the liver, where it can cause primary liver cancer. It crosses the placenta into the embryo and, like the drug thalidomide, causes gross birth deformities. 

We will discuss -• Low Level Radioactive Waste• High Level Radioactive Waste• Transuranic Waste

CLASSIFICATIONS• Nuclear  waste  is  segregated  into  several classifications.

• Low  level  waste  is  not  dangerous  but sometimes requires shielding during handling.

• Intermediate  level  waste  typically  is  chemical sludge and other products from reactors.

• High  level  waste  consists  of  fissionable elements  from  reactor  cores  and  transuranic wastes.

• Transuranic    waste  is  any  waste  with transuranic  alpha  emitting  radio  nuclides  that have half-lives longer than 20 years.

LOW LEVEL WASTE(LLW)

• Low level waste is any waste that could be from a high activity area.

• 90% volume of waste• It does not necessarily

carry any radioactivity.• Split into four categories :

A, B, C, and GTCC.

INTERMEDIATE LEVEL WASTE(ILW)

• Intermediate level waste requires shielding when being handled.

• 7% volume of waste• Dependent on the amount of

activity it can be buried in shallow repositories.

• Not recognized in the United States.

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 about 12,000 metric tons per year.

• Most HLW consists of Pu-238, 239, 240, 241, 242, Np-237, U-236

TRANSURANIC WASTE(TRUW)

• Transuranic waste consists of all waste that has radionuclides above uranium.

• TRUWs typically have longer half-lives than other forms of waste.

• Typically a byproduct of weapons manufacturing.• Only recognized in the United States.

SOURCES OF NUCLEAR WASTE

•Nuclear waste is generated at all points of the fuel cycle.•Front end waste consists primarily of low level alpha emission waste.•Service period waste typically includes LLW and ILW such as contaminated reactor housings and waste from daily operation.•Back end waste normally is the most radioactive and includes spent fuel rods and reactor cores.

FRONT END WASTE

• Front end waste consists mostly of LLW and ILW.• The  primary  front  end  waste  is  depleted  uranium  and radium.  

• DU has several uses due to its high density (19,050 kg/m3).• Mix with uranium to form reactor fuel

SERVICE PERIOD WASTE

• Consists of mostly ILW.• Mostly  waste  produced  at  the  plant  during  normal operation.

• Spent  fuel  rods  are  the most  dangerous waste  produced during the service period.

BACK END WASTE

• Nuclear waste developed during the back end of the fuel cycle is the most dangerous and includes most of the HLW produced.

• Most back end waste emits both gamma and beta particles.

• Also uranium-234, neptunium-237, plutonium-238 and americium-241are found in back end waste.

Spent nuclear fuel in a cooling pond in NorthKorea.

LOW LEVEL RADIOACTIVE WASTE

Low Level Radioactive waste consists of micro curie, milli- curie and at times curie activity waste.

(A Curie is a unit of nuclear transformations. 1 Curie is 3.7 x1010 transformations per second)

• Low level radioactive waste consists of:• Contaminated solids• liquids• animal carcasses• small sealed sources

WASTE MANAGEMENT (LLW)

• There are several options available for the disposal of LLW due to its lack of radioactivity.

• Waste Isolation Pilot Plant

• On-site disposal

Map of WIPP Facility

• Low level radioactive liquids are either:• Incinerated• Deep well injected (not as frequent anymore)• Solidified• Sewer Disposed (Regulations allow curie levels of some isotopes to be sewer disposed of if dilution is large enough)

• Radioactive animal carcasses are either incinerated or buried onsite.  

• Small sealed sources are “Stabilized” in concrete and buried.   Stabilized concrete is concrete that is certified to resist wear for a certain time period.

• Low level contaminated solid wastes are buried.  GSU has it’s solid waste “Supercompacted” at 30,000 psi to reduce the volume to be buried

MOST LOW LEVEL WASTES COME FROM GOVERNMENT AND UTILITIES. THESE CONSIST OF CONTAMINATED SOLIDS FROM NUCLEAR REACTOR USAGE AND WEAPON CONSTRUCTION.

• Colleges, research and medical applications account for less than 25% of the low level Radioactive wastes created 

• There are 3 LLRW Burial  sites:

• Hanford• Envirocare• Barnwell

N.I.M.B.Y.Not InMyBackYard

The true politics of Hazardous Waste

NIMBY: NOT IN MY BACK YARD• Fear of radiation because they don’t understand it• Concern that the waste facility willrelease long-term contamination

• Worry that property values will be reducedwith construction of a waste facility

• Belief that power companies are the ones                                 responsible  for storing their own waste

• People don’t want dumped on by otherpeoples’ waste

• Belief that nuclear power should just goaway and be replaced by other energyresources

• Environmental concerns

LOW-LEVEL DISPOSAL SITES

TYPICAL LOW-LEVEL WASTE DISPOSAL SITE

Hanford (Nuclear News, November 2004)

• Filtration

• Ion Exchange

• Evaporation

• Incineration

• Compaction

• Solidification

Typical LLW treatment facility.

• Most common utilized option are reactor pools and dry cask storage.

• Other Options for waste management include:

• Deep Geologoical Storage

• Transmutation

• Reuse

• Launching it into space

Locations of storage sites for nuclear waste in the U.S.

• High-Level Radioactive Waste is: the irradiated fuel from the cores of nuclear  reactors,  the  liquid  and sludge  wastes  that  are  left  over after  irradiated  fuel  has  been reprocessed  (a  procedure  used  to extract  uranium  and  plutonium), the  solid  that  would  result  from efforts  to  solidify  that  liquid  and sludge from reprocessing. 

Because there is currently no high level radioactive waste disposal facility, HLRW is held On-Site in water pools

Once these Pools are full, Waste is transferred to casks which are also held on-site

A HLRW repository is being constructed at Yucca Mountain in Nevada to hold all this waste.  NIMBY again is playing a role in the opening

CURRENT HIGH-LEVEL WASTE STORAGE IN THE US

www.nei.org

TRANSPORTATION CONCERNS

• Most common initial treatment of waste is vitrification.• Waste  is  first  mixed  with  sugar  and  then  passed through a heated tube to de-nitrite the material.

• This material is then fed into a furnace and mixed with glass.

• The molten glass mixture is poured into steel cylinders and welded shut.

• Mid level active waste is commonly treated with ion exchange

• Process reduces the bulk volume of radioactive material.• Typically, mixed with concrete for a solid storage form.

• Most common method for handling nuclear waste.

• Typically kept separate from actual plants and buried far below ground.

• First used in 1999 in the US.

• Current research is focusing on Yucca Mountain. Yucca Mountain Site

• Reduces transuranic waste.  • Integral Fast Reactor• Banned 1977-1981 (U.S.)• MOX Fuel• Behaves as low-enriched uranium• Research now in subcritical reactors.• Fusion also being researched.

• Research is being performed to find uses for nuclear waste.

• Caesium-137 and strontium-90 already used in industrial applications.

• Some waste can be used for radioisotope thermoelectric generators (RTGs).  

• Overall can reduce total HLW but not eliminate it.

LAUNCH IT INTO SPACE

• Near infinite storage space

• Completely removes waste from biosphere

• Technical risks and problems

• Political entanglements

For more information, http://www.ocrwm.doe.gov/ymp/index.shtml

Yucca Mountain• Technically sound

• 1,000’ below ground

• Repository in block of solid rock

• 1,000’ above water table

• Remote location on Nevada Test Range

It is better to have used nuclear fuel in one location

DEEP GEOLOGIC REPOSITORY

BUILT FOR300 YEARS OF RETRIEVAL10,000 YEARS OF STORAGE

WASTE ISOLATIONPILOT PLANT

• Opened March 26, 1999• Storage of transuranic waste leftover from research an production of nuclear weapons

• http://www.wipp.energy.gov/

• http://www.radiochemistry.org/wipp_tour/index.html

PRIVATE FUEL STORAGE(SKULL VALLEY, UTAH)

• Temporary storage of spent nuclear fuel until Yucca Mountain is operational

• Goshute Indian Skull Valley Band

• 3-ft thick concrete storage pads

http://www.privatefuelstorage.com/ http://www.kued.org/skullvalley/

MAYAPURI………

Mayapuri scrap market is a well known area of Delhi. There are around 200 scrap shops in the market. This area came into limelight when a radiation incident which makes five people seriously injured came in to existence.

WHAT IS COBALT – 60?

Cobalt-60 (60Co) is a radioactive isotope of cobalt. Due to its short half life of 5.27 years 60Co is not found in nature. It is produced artificially by neutron activation of 59Co. 60Co decays by negative beta decay to the stable isotope nickel-60 (60Ni). ...

FROM WHERE DID IT COME??

 

 A gamma irradiator  no longer in use since 1985 in a chemistry laboratory at Delhi University was auctioned in a scrap market of Mayapuri in February 2010.The orphan source was sent to one of the many scrap yards existing at Mayapuri and dismantled by workers. During the demolishing operations to recover metal scraps, the lead shielding protecting the radioactive source was removed and the source itself damaged. And the Cobalt – 6o leaked into the environment.

• Deepak Jain a scarp dealer merchant purchased some scarp from the City Hospital which is covered in a plastic sheet when Deepak removed this sheet radiation begins to start, Deepak was not aware of this he got serious burn injuries and black marks on the skin, He was taken to the Apollo Hospital which informed the government that he had suffered radiation as told by officials. Four other workers in his factory also came in the range of this harmful radiation and got the burn injuries.

• HLW is most dangerous byproduct of nuclear power.

• Borosilicate glass most common storage.

• Several venues being researched for the safe disposal of HLW.