ML20033F870
| ML20033F870 | |
| Person / Time | |
|---|---|
| Issue date: | 09/22/1988 |
| From: | Knapp M NRC |
| To: | |
| Shared Package | |
| ML20033F868 | List: |
| References | |
| REF-WM-1 NUDOCS 9004040008 | |
| Download: ML20033F870 (8) | |
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LOW-LEVEL WASTE REGULATIONS
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l; t PRESENTED-3Y MAI.COLH R. KNAPP h
ulNCOLN, NEBRASKA SETPEMBER 22, 1988 i'
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9004040008 900327 PDR WASTE WM-1 PDC
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1 LOW-tEVEL WASTE REGULATIONS l
J Good morning.
I'm here to speak about low-level radioactive waste (LLW) 1 disposal regulations on behalf of the huclear Regulatory Commission (NRC).
I'll first give some general information about LLW: what it is, what it isn't, and where it comes from.
I'll then provide some background on LLW disposal at existing sites around the t.ountry and move on to an overview of our LLW cisposal regulations contained in Title 10, Code of Federal Regulations, Part i
61.
Finally, I'll talk about how we expt.ct a !.LW disposal site licensed undar those regulations to work.
j LOW-LEVEL WASTES Radioactive wastes are generally dividad into four categories. These are:
Low-Level Wastes Uranium Mill Tailings Transuranic Wastes High-Level Wastes Low-level waste is waste other than mill tailings whose radioactivity is too low for it to be considered either transuranic waste or high level waste. LLW includes materials such as ion exchange resins and activated metals from reactors, solidified and absorbed liquids, failed equipment, compacted trash, contaminated protective clothing, animal carcasses, and decontamination wastes.
Only LLW will be disposed of at State or Compact disposal facilities. Uranium mill tailings are being disposed of in stable piles that are covered with earth and rock, generally in the western part of the United States. Transuranic wastes are to be buried by DOE near Carlsbad, New Mexico. High-level wastes are planned to be buried about 1,000 feet underground at Yucca Mountain, Nevada.
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LLW is generated in the United States by more than 23,000 NRC or Agreement State licensees, including nuclear reactor operators, hospitals, research laboratories, ' universities, industry, and the government (Source:
NRC 1986 l
AnnualReport).
In 1987, these licensees generated about 1,850,000 cubic feet of LLW which contained roughly 260,000 curies of radioactivity.
By volume, roughly 57 percent of disposed LLW is generated by reactors, 9 percent from industrial sources, 32 percent from institutional sources, and 2 percent from the government and military. Thecorrespondingradioactivity(curies) distribution is 65 percent reactors, 32 percent indcstrial. 0.4 percent insti%tiotal, and 3 percent government and miMtary l% tree: DOE /RW 006, Rev.
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o, EXISTING DISPOSAL SITES This country's commercial LLW has been disposed of at sh Sites. All six use shallow land burial and all were developed 6nd licensed before NRC's present LLW regulations were established. Three sites are now open, three have been closed. The open sites are near Barnwell, South Carolina; Beatty, Nevada; and Hanford, Washington.
The closed sites are near Maxey Flats in Kentucky, Sheffield in Illinois, and l
West Valley in New York.
Several problems have occurred at these sites. As time has passed some wastes have consolidated and collapsed, causing some of the disposal trenches to settle and become depressions in the ground. These depressions can collect rain and therefore increase contact of water with the disposed waste.
Site and ground water conditions around the trenches at these sites combined with waste consolidation also led to releases of radionuclides from the disposal trenches through surface and ground water.
(Nosignificant releases of radioactivity offsite have occurred.)
The lessons learned at these sites had a significant impact on the development of NRC's LLW disposal regulation. It has been written to prohibit the site
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selection and waste disposal practices that led to the problems at the closed s
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The NRC considers that the performance of the three operating sites has i
been much better than the closed sites, due.to good site selection l
and better shallow land burial techniques.
In addition, the site licenses have been upgraded to reflect Part 61 requirements. The first slide is a disposal trench at Barnwell being filled with LLW.
NRC'S DISPOSAL REGULATIONS t
At the heart of NRC's 10 CFR Part 61 are four performar.ce Ajectives developed expressly fer the neer-surface ditpotal of LLW. These are:
Protection of the general population from releases of radioactivity.
Protection of indiviouals from inadvertent intrusion, Protection of individuals during operations, and Stability of the site after closure.
In more detail, protection of the general population from releases of radioactivity is accomplished by requiring that the concentrations of radioactive material released to the general environment shall not exceed an annual dose equivalent to 25 mrem to the whole body, 75 mrem to the thyroid, and 25 mrem to any other organ of any member of the public, and, beyond that, doses are to be kept as low as reasonably achievable.
(10CFRPart61.41)
Protection of individuals from inadvertent intrusion is accomplished by requiring the design, operation, and closure of the site must ensure protection of any individual inadvertently intruding into the disposal facility after active institutional controls at the facility have been removed. (10 CFR Part 61.42) The NRC intends this objective to limit the dose to the intruder to about 500 mrem per year.
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5 Protection of individuals during operations is accomplished by requiring that, except for offsite releases (which are limited by 10 CFR Part 61.41 above),
operations at the disposal facility shall be conducted in compliance with the standards for radiation protection set out in 10 CFR Part 20, and beyond that, kept as low as reasonably achievable.
(10CFRPart61.43)
Stability of the site after closure is accomplished by requiring that the disposal facility shall be sited, designed, utilized, operated, and closed to achieve long-term stability of the site and to eliminate, to the extent practicable, the need for ongoing active maintenance following closure, so that only surveillance, monitoring, or minor custodial care are required. This objective and the technice.1 requiremants which suppurt it, were established to 3
l minimize tretch Jettlenent and subsidence.
(10CFRPart61.44)
There are, of course, additional requirem nts in 10 CFR Part 61 to ensure that 1
the performance objectives are net. These include site selection criteria that
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saek :acdelabla, well draf.ed sites whtre wastes vill be disposed of above the t
i water table, and avoid sites that might be subject to erosion, or geologic faults, or that are located in flood plains.
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in another part of the regulation, the NRC has established a classification system for LLW. There nre three classes, in ascending order of hazard, Class A, Class B, and Class C.
For each class, NRC regulations set concentration limits for both short-lived and long-lived radionuclides. These limits are actually formulas that reflect both the half-lives and the hazards of the radionuclides in each class. A rule of thumb is that Class A waste is intended l
to be relatively safe after 100 years, Class B after 300 years, and Class C af ter 500 years. Table 1 below shows the classification of 1987 LLW.
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TABLE 1 I
f Waste Class Volume Activity i
3 FT Curies A
1,794,000 97 16,000 06 8
39,000 02 67,000 26 C
9.000 0.5 176.000 68 j
1,642,000 260.000 i
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The waste classification system is used to implerent 1 perfoteenit objettiyes through establishing different criteria for tne dhposal 'Ji each clan of waste. Ttue nre; t
Class A Waste is segregated from other waste at the dhpesti site a;id t.isposed I
of with minimum requirements on waste form and characteristics.
Class B Waste must meet both minimum and stability requirements on form and characteristics.
Class C Waste must meet both minimum and stability requirements and must be protected from inadvertent intrusion by deeper burial or other barriers. These i
requirements are also shown in Table 2 below.
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l Table 2 Site, Design and Institutional Waste Intruder j
Operations Controls.
Form.
Barrier l
Class A X
X i
i Class B X
X X
Class C X
X X
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'the intended perfe m nce cf a LLW disposal thcO tty that conforms to these crbria is chuvn in faur slides, and discusseri below.
L As seen in the first of these slides, Citts A waste is segregated from Class B i
and C w;aste,~and Class C waste is placed at the bottom of its disposal ur.it., so j.
that it is separated f rom the surf ace by at least 5 metes. At least 2 meters l
of cover is placed over the top of each disposal unit.
t In the second slide, during the first 100 years, the Class A waste consolidates and begins to merge with the surrounding soil.
Class B and C waste remain stable.
The third slide shows 100 to 300 years. After 100 years, Class A wastes may be l
consolidated and unrecognizable; inadvertent intrusion into these wastes would L
be safe. Class B and C wastes continue to maintain their integrity, and remain recognizable, thus reducing the likelihood of inadvertent intrusion, for up to 300 years af ter closure. An applicant may not, however, take credit for active institutional controls for more than 100 years. The disposal facility must be built so that, without active institutional controls after 100 years, the pub 1'c will be properly protected.
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The fourth slide shows 300 to 500 years. At 300 years, it is expected that the Class-B and C wastes will begin cisintegrating.
It will be safe to intrude into Class B wastes: The additional depth or barriers associated with Class C wastes are expected to provide (ntruder protection between 300 and 500 years after closure. After 500 years, all wastes.are presumed to be consolidated and unrecognizable, and inadvertent intrusion would be safe.
To summarize, today I've talked about what low-level wastes are, their disposal at some existing sites, the NRC's disposal regulations, and how we expect new sites licensed under those regulations to perform. I look forward to answering your questions this afternoon.
Thank you.
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