Low-level waste
The examples and perspective in this article deal primarily with the United States and do not represent a worldwide view of the subject. (December 2010) |
Low-level waste (LLW) or Low-level radioactive waste (LLRW) is
LLW includes items that have become contaminated with radioactive material or have become radioactive through exposure to neutron radiation. This waste typically consists of contaminated protective shoe covers and clothing, wiping rags, mops, filters, reactor water treatment residues, equipments and tools, luminous dials, medical tubes, swabs, injection needles, syringes, and laboratory animal carcasses and tissues. The radioactivity can range from just above background levels found in nature to very highly radioactive in certain cases such as parts from inside the reactor vessel in a nuclear power plant.
The definition of low-level waste is set by the nuclear regulators of individual countries, though the International Atomic Energy Agency (IAEA) provides recommendations.[1] Some countries, such as France, specify categories for long-lived low- and intermediate-level waste. U.S. regulations do not define the category of intermediate-level waste.
Disposal
Depending on who "owns" the waste, its handling and disposal is regulated differently. All nuclear facilities, whether they are a utility or a disposal site, have to comply with
Classes of wastes are detailed in 10 C.F.R. § 61.55 Waste Classification,[4] enforced by the Nuclear Regulatory Commission, reproduced in the table below. These are not all the isotopes disposed of at these facilities, just the ones that are of most concern for the long-term monitoring of the sites. Waste is divided into three classes, A through C, where A is the least radioactive and C is the most radioactive. Class A LLW is able to be deposited near the surface, whereas Classes B and C LLW have to be buried progressively deeper.
In 10 C.F.R. § 20.2002, the NRC reserves the right to grant a free release of radioactive waste. The overall activity of such a disposal cannot exceed 1 mrem/yr and the NRC regards requests on a case-by-case basis. Low-level waste passing such strict regulations is then disposed of in a landfill with other garbage. Items allowed to be disposed of in this way are: glow-in-the-dark watches (radium) and smoke detectors (americium) among other things.
Radionuclide | Class A (Curies/m3) | Class B (Ci/m3) | Class C (Ci/m3) (upper limit for LLW) |
---|---|---|---|
Total of all nuclides with less than 5-year half life
|
700 | No limit | No limit |
Tritium (3H) | 40 | No limit | No limit |
Cobalt-60 (60Co) | 700 | No limit | No limit |
Nickel-63 (63Ni)
|
3.5 | 70 | 700 |
Ni-63 in activated metal | 35 | 700 | 7000 |
Strontium-90 (90Sr) | 0.04 | 150 | 7000 |
Cesium-137 (137Cs)
|
1 | 44 | 4600 |
Carbon-14(14C) | 0.8 | 8 | |
C-14 in activated metal | 8 | 80 | |
Nickel-59 (59Ni) in activated metal
|
22 | 220 | |
Niobium-94 (94Nb) in activated metal
|
0.02 | 0.2 | |
Technetium-99 (99Tc) | 0.3 | 3 | |
Iodine-129 (129I) | 0.008 | 0.08 | |
transuranic nuclideswith a half life greater than 5 years |
10 nCi/g | 100 nCi/g | |
Plutonium-241 (241Pu) | 350 nCi/g | 3500 nCi/g | |
Curium-242 (242Cm)
|
2000 nCi/g | 20000 nCi/g |
LLW should not be confused with
See also
- Low Level Waste Repository
- Mixed waste (radioactive/hazardous)
- Radioactive waste
- Spent nuclear fuel
- Transuranic waste
References
Notes
- ^ "Classification of Radioactive Waste : a Safety Guide. Safety Series No. 111-G-1.1" (PDF). RADWASS Programme. Vienna: IAEA. 1994. Archived from the original (PDF) on 15 May 2005.
- ^ "Disposal of Commercial Low-Level Radioactive Waste". Nuclear Energy Institute. April 2014. Retrieved 8 May 2015.
- ^ "New Federal Waste Facility Opens with Ribbon Cutting Ceremony" (PDF). Waste Control Specialists. 6 June 2013. Archived from the original (PDF) on 23 May 2014. Retrieved 9 May 2015.
- ^ official online version of 10 C.F.R. § 61.55 Waste Classification
General references
- Fentiman, Audeen W. and James H. Saling. Radioactive Waste Management. New York: Taylor & Francis, 2002. Second ed.
- Jorge L. Contreras, "In the Village Square: Risk Misperception and Decisionmaking in the Regulation of Low-Level Radioactive Waste", 19 Ecology Law Quarterly 481 (1992) (SSRN)