science

Low-level waste

Low-level waste is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Low-level waste rather than just read about it. In short: Low-level waste (LLW) or low-level radioactive waste (LLRW) is a category of nuclear waste. The definition of low-level waste is set by the nuclear regulators of individual countries, though the International Atomic Energy Agency (IAEA) provides recommendations.

Key takeaways

Low-level waste belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Low-level waste to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Low-level waste from memory before moving on to harder problems.

Reference excerpt

Low-level waste (LLW) or low-level radioactive waste (LLRW) is a category of nuclear waste. The definition of low-level waste is set by the nuclear regulators of individual countries, though the International Atomic Energy Agency (IAEA) provides recommendations. 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.

LLW in the United Kingdom In the UK, LLW is defined as waste with specific activities below 12 gigabecquerel/tonne (GBq/t) beta/gamma and below 4 GBq/t alpha emitting nuclides. Waste with specific activities above these thresholds are categorised as either Intermediate-level waste (ILW) or high heat generating waste depending upon the heat output of the waste. Very Low Level Waste (VLLW) is a sub-category of LLW. VLLW is LLW that is suitable disposal with regular household or industrial waste at specially permitted landfill facilities. The major components of VLLW from nuclear sites are building rubble, soil and steel items. These arise from the dismantling and demolition of nuclear reactors and facilities.

LLW in the United States

LLW in the United States is defined as nuclear waste that does not fit into the categorical definitions: high-level waste (HLW), spent nuclear fuel (SNF), transuranic waste (TRU), or certain byproduct materials known as 11e(2) wastes, such as uranium mill tailings. In essence, it is a definition by exclusion, and LLW is that category of radioactive wastes that do not fit into the other categories. If LLW is mixed with hazardous wastes as classified by RCRA, then it has a special status as mixed low-level waste (MLLW) and must satisfy treatment, storage, and disposal regulations both as LLW and as hazardous waste. While the bulk of LLW is not highly radioactive, the definition of LLW does not include references to its activity, and some LLW may be quite radioactive, as in the case of radioactive sources used in industry and medicine. It is notable that U.S. regulations do not define the category intermediate-level waste and thus many wastes which would fall into this category under other regulatory regimes are instead classified as LLW. This also means that the radioactive of LLW in the US 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.

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 Nuclear Regulatory Commission (NRC) regulations. The four low-level waste facilities in the U.S. are Barnwell, South Carolina; Richland, Washington; Clive, Utah; and as of June 2013, Andrews County, Texas. The Barnwell and the Clive locations are operated by EnergySolutions, the Richland location is operated by U.S. Ecology, and the Andrews County location is operated by Waste Control Specialists. Barnwell, Richland, and Andrews County accept Classes A through C of low-level waste, whereas Clive only accepts Class A LLW. The DOE has dozens of LLW sites under management. The largest of these exist at DOE Reservations around the country (e.g. the Hanford Reservation, Savannah River Site, Nevada Test Site, Los Alamos National Laboratory, Oak Ridge National Laboratory, Idaho National Laboratory, to name the most significant). Classes of wastes are detailed in 10 C.F.R. § 61.55 Waste Classification, 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 include glow-in-the-dark watches (radium) and smoke detectors (americium).

LLW should not be confused with high-level waste (HLW) or spent nuclear fuel (SNF). C Class low-level waste has a limit of 100 nanocuries per gram of alpha-emitting transuranic nuclides with a half-life greater than 5 years; any more than 100 nCi, and it must be classified as transuranic waste (TRU). These require different disposal pathways. TRU wastes from the U.S. nuclear weapons complex is currently disposed at the Waste Isolation Pilot Plant (WIPP) near Carlsbad, New Mexico, though other sites also are being considered for on-site disposal of particularly-difficult-to-manage TRU wastes.

See also Low Level Waste Repository Mixed waste (radioactive/hazardous) Radioactive waste Spent nuclear fuel Transuranic waste

References

Notes

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)

External links NRC description of low-level waste

Illustrations

Worked examples

Example 1 — a first encounter with Low-level waste

Start with the simplest possible case. Write down what Low-level waste claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Low-level waste before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Low-level waste ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Low-level waste

In research: Low-level waste appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Low-level waste in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Low-level waste is common in secondary-school and first-year university syllabi. It links to neighbouring topics Radioactive waste, so understanding it makes those chapters shorter.
In everyday life: Look for Low-level waste outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Low-level waste in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Low-level waste means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Low-level waste out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Low-level waste in simple terms?

Why does Low-level waste matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Low-level waste?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Low-level waste.