1. Fuel Cycle – High Level Waste Disposal
Sources of Radiation
Fuel Cycle – High Level Waste Disposal
Day 4 - Lecture 8 (3)

2. High Level Waste Disposal

3. High Level Waste Disposal
At the present time, there are no disposal facilities (as opposed to storage facilities) in operation in which spent fuel, not destined for reprocessing, and the waste from reprocessing can be placed. Although technical issues related to disposal have been addressed, there is currently no pressing technical need to establish such facilities, as the total volume of such wastes is relatively small. Further, the longer it is stored the easier it is to handle, due to the progressive diminution of radioactivity. There is also a reluctance to dispose of spent fuel because it represents a significant energy resource which could be reprocessed at a later date to allow recycling of the uranium and plutonium.

4. High Level Waste - HLW
Refers to long-life wastes from reprocessing (“first-cycle aqueous raffinate”) except in USA where there is currently no reprocessing
From Purex reprocessing, one 175 liter can containing 150 liters of HLW glass from 2 MTHM of SNF (better than 5:1 volume reduction)
DOE vitrified HLW uses 625 liter can
Dry storage of HLW containers

5. Vitrified High Level Waste
Loading silos with canisters containing vitrified high‑level waste in UK, each disc on the floor covers a silo holding ten canisters
A number of countries are carrying out studies to determine the optimum approach to the disposal of spent fuel and waste from reprocessing. The most commonly favoured method for disposal being contemplated is placement into deep geological repositories.
Wastes from the nuclear fuel cycle are categorised as high‑, medium‑ or low‑level waste by the amount of radiation that they emit. These wastes come from a number of sources and include:
* low‑level waste produced at all stages of the fuel cycle
* intermediate‑level waste produced during reactor operation and by reprocessing
* high‑level waste, which is waste containing fission products from reprocessing, and in many countries, the spent fuel itself.
The 3% of the spent fuel which is separated high‑level wastes amounts to 700 kg per year and it needs to be isolated from the environment for a very long time. These liquid wastes are stored in stainless steel tanks inside concrete cells until they are solidified.
After reprocessing the liquid high‑level waste can be calcined (heated strongly) to produce a dry powder which is incorporated into borosilicate (Pyrex) glass to immobilise the waste. The glass is then poured into stainless steel canisters, each holding 400 kg of glass. A year's waste from a 1000 MWe reactor is contained in 5 tonnes of such glass, or about 12 canisters 1.3 metres high and 0.4 metres in diameter. These can be readily transported and stored, with appropriate shielding. This is as far as the nuclear fuel cycle goes at present.

6. Yucca Mountain Nevada USA
In USA high‑level civil wastes all remain as spent fuel stored at the reactor sites. Some HLW is also stored at Department of Energy sites. It is planned to encapsulate these fuel assemblies and dispose of them in an underground engineered repository about 2010, at Yucca Mountain, Nevada. This is the program which has been funded by electricity consumers to US$ 18 billion 0.1 cent per kWh), of which about US$ 6 billion has been spent.
In Europe some spent fuel is stored at reactor sites, similarly awaiting disposal. However, much of the European spent fuel is sent for reprocessing at either Sellafield in UK or La Hague in France. The recovered U and Pu is then returned to the owners (the Pu via a MOX fuel fabrication plant) and the separated wastes (about 3% of the spent fuel) are vitrified, sealed into stainless steel canisters, and either stored or returned. Eventually they too will go to geological disposal.
Sweden represents the main difference, it has centralised spent fuel storage, CLAB, near Oskarshamn, and will encapsulate spent fuel there for geological disposal by about Finland is establishing a final repository for spent fuel at Olkiluoto. European funding is at similar level to the USA per kWh.

7. Yucca Mountain Nevada USA
This is the NRC’s overview of the proposed HLW repository taken from its website.

8. HLW Disposal Canisters
The waste forms envisaged for disposal are either vitrified high‑level wastes sealed into stainless steel canisters, or, as is the case in the United States, spent fuel rods encapsulated in corrosion‑resistant metals such as copper or stainless steel as seen in this slide.

9. Transuranic Waste Disposal
The US has some experience with a permanent geological repository for transuranic waste at the Waste Isolation Pilot Project (WIPP) in Carlsbad New Mexico. The waste is packaged in 220 liter drums which are themselves overpacked into TRUPAC containers for transport to the site.
Waste Isolation Pilot Project (WIPP)

10. Transuranic Waste Disposal
This is a schematic of the WIPP facility.

11. Transuranic Waste Disposal
The Transport containers are unloaded and the 220 liter drums are placed in the repository which is a salt bed.

12. Material Balance in the
Nuclear Fuel Cycle
Typical for the operation of a 1000 MWe nuclear power reactor
Mining 22,400 tonnes of 1% uranium ore
Milling 280 tonnes of uranium oxide
concentrate (224 t U)
Conversion 331 tonnes UF6 (with 224 t U)
Enrichment 35 tonnes UF6 (with 24 t enriched U,
balance is tails)
Fuel Fabrication 27 tonnes UO2 (with 24 t enriched U)
Reactor Operation 7,000 million kWh of electricity
Spent Fuel 27 tonnes containing 240kg plutonium,
23 t uranium (0.8% U-235), 720kg fission
products, also transuranics
Material balance in the nuclear fuel cycle
The table makes various assumptions but may be regarded as typical for the operation of a 1000 MWe nuclear power reactor

13. Where to Get More Information
The Uranium Institute
The Uranium Information Centre
Institute for Energy and Environmental Research
Agency for Toxic Substances and Disease Registry (HHS)
Australian Academy of Science

14. Where to Get More Information
World Information Service on Energy (WISE Uranium Project)
International Atomic Energy Agency (IAEA)
US DOE Environmental Management
USDOE Energy Information Administration
USNRC