[Federal Register Volume 59, Number 38 (Friday, February 25, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-4294]
[[Page Unknown]]
[Federal Register: February 25, 1994]
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NUCLEAR REGULATORY COMMISSION
10 CFR Part 20
RIN 3150-AE90
Disposal of Radioactive Material by Release into Sanitary Sewer
Systems
AGENCY: Nuclear Regulatory Commission.
ACTION: Advance notice of proposed rulemaking.
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SUMMARY: The Nuclear Regulatory Commission (NRC) is seeking information
to determine whether an amendment to its regulations governing the
release of radionuclides from licensed nuclear facilities to sanitary
sewer systems is needed. The potential rulemaking would revise the
approach to limiting the release of radioactive materials into sanitary
sewer systems by licensed nuclear facilities based on current sewer
treatment technologies. This advance notice of proposed rulemaking is
being issued to invite comments, information, and recommendations from
interested parties on the issues that have been identified as
candidates for consideration as part of this rulemaking.
DATES: The comment period expires May 26, 1994. Comments received after
this date will be considered if it is practical to do so, but the
Commission is able to assure consideration only for comments received
on or before this date.
ADDRESSES: Mail comments to: The Secretary of the Commission, U.S.
Nuclear Regulatory Commission, Washington, DC 20555, Attention:
Docketing and Service Branch.
Deliver comments to: 11555 Rockville Pike, Rockville, Maryland,
between 7:45 a.m. and 4:15 p.m. Federal workdays.
Examine copies of comments received at: The NRC Public Document
Room, 2120 L Street NW. (Lower Level), Washington, DC.
Copies of NUREG/CR-5814, which supports this advance notice, may be
purchased from the Superintendent of Documents, U.S. Government
Printing Office, P.O. Box 37082, Washington, DC 20013-7082. Copies are
also available from the National Technical Information Service, 5285
Port Royal Road, Springfield, VA 22161. A copy is also available for
inspection and/or copying, for a fee, at the NRC Public Document Room,
2120 L Street, NW. (Lower Level), Washington, DC.
FOR FURTHER INFORMATION CONTACT: Dr. George E. Powers, Office of
Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission,
Washington, DC 20555, telephone (301) 492-3747.
SUPPLEMENTARY INFORMATION:
Background
The Nuclear Regulatory Commission regulates the release of
radioactive material by licensees into sanitary sewer systems under 10
CFR part 20. The basis for the NRC's sewer release requirements was
established over 35 years ago. The NRC and Agreement States have become
aware of instances where radioactive material has been detected in
sewage treatment systems. Examination of several of these cases led the
Commission to modify the requirements for disposal of radioactive
materials into sanitary sewers as part of the revised standards for
protection against radiation added to 10 CFR part 20 (56 FR 23360; May
21, 1991). In particular, the Commission removed the provision (except
for the case of biologically dispersible materials) which allowed the
disposal of dispersible materials into sewers because it appeared that
dispersible, but insoluble materials, were generally implicated in the
sewer sludge contamination cases. In addition, the concentrations
allowed for various radionuclides released to sewers were reduced by a
factor of 10, as part of an overall reduction in effluent release
limits. The concentrations listed in Table 3 of appendix B to 10 CFR
part 20 were calculated on the basis of a 5 mSv (500 mrem) dose via
ingestion of material at the discharge point from the licensee. The
concentrations listed in Table 3 were considered reasonable since it is
unlikely that any individual would actually consume water at the point
of discharge and since dilution from additional contributions within
the sanitary sewer would likely reduce levels to well below the 1 mSv
(100 mrem) annual dose limit for members of the public. The provisions
permitting the release of soluble material and the total quantities of
material which could be released in any one year were retained in the
revision to 10 CFR part 20.
These provisions have been effective since June 1991. However,
licensees have until January 1, 1994, to comply with the requirements.
In promulgating the revised standards for protection against radiation,
the NRC acknowledged that additional information was necessary
regarding potential pathways of exposure and radiation doses that could
result from releases into sanitary sewers, particularly in light of new
sewerage treatment systems that further concentrate solids and are used
by large municipalities. The NRC is publishing this advance notice to
obtain public comment on a number of issues associated with the release
of radioactive material to sewer systems. This information will be used
in evaluating what additional changes to the requirements in 10 CFR
part 20 may be necessary. This information will also be used in
assessing the impacts of the various options that may be available for
imposing any necessary additional requirements.
Discussion
There are approximately 15,000 sewer treatment plants (STPs) in the
United States and 23,000 specifically licensed users of radioactive
materials. It is not uncommon for several licensed radioactive
materials users to discharge radioactive waste materials into the same
sewerage system. Sewage treatment plants (STP) vary in size (capacity)
from less than 1 million gallons per day (gpd) to over 1 billion gpd. A
capacity of 1 million gpd would serve about 5000 people and a few small
commercial users. A 1 billion gpd facility would accommodate a
population of about 5 million people and a substantial industrial base.
The sewage treatment process, the size of the sewage treatment
facility, and the amount, as well as the physical and chemical form, of
the radioactive materials released to the sewer system can have a
significant effect on the fate of the radioactive materials in the
process and the final concentrations of materials in the sewer sludge
or ash.
A number of incidents of radioactive material contamination and
reconcentration have occurred. A description of some of these cases is
included at the end of this notice. It should be noted that each of
these cases occurred prior to implementation of the revised part 20
limits for releases of radioactive material to sewer systems.
In 1989, the NRC contracted with Battelle, Pacific Northwest
Laboratories (PNL), to study situations where radioactivity has been
reported in sewer systems or sewer treatment sludge. The results of the
PNL study were published in May 1992 as NUREG/CR-5814, ``Evaluation of
Exposure Pathways to Man from Disposal of Radioactive Materials Into
Sanitary Sewer Systems.'' NUREG/CR-5814 includes information on sewage
treatment and disposal practices, and exposure pathways and scenario
analysis, based on case studies of situations where radioactive
contamination has been reported in sewer systems or in sewer treatment
sludges.
The PNL study performed theoretical modeling of most types of
licensee radioactive discharges, except for excreta from individuals
undergoing medical diagnostic or therapeutic administrations of
radioactive material, which are exempt from regulation under
Sec. 20.2003. Modeling scenarios estimated the exposure to individuals
at the sewer treatment facility and as a result of various uses of
sewage sludges resulting from treatment. The results of the study
predicted doses of 0.2 to 93 mrem/yr total effective dose equivalent
(TEDE). The assumptions used in the study were that all material was
released at the part 20 limit and subsequently reconcentrated. Thus,
the doses calculated represent an upper bound of possible doses to
actual individuals.
Request for Information and Comment
The Commission requests comments and information on a number of
issues related to requirements for disposal of radioactive material
into sanitary sewers. This request for comments and information is in
the context of evaluating the options which may be available to the
Commission to provide additional or alternative means of regulatory
control over releases into sanitary sewers. The comments and
information which will be particularly useful are those related to the
impacts of various alternatives for each issue, including impacts on
various types of licensees such as biomedical and university research
licensees.
(1) Form of the Material for Disposal.
The standards for protection against radiation in 10 CFR part 20
permit the disposal of materials into the sanitary sewer if they are
soluble or readily dispersible biological materials. Formerly, the
release of dispersible non-biological material was permitted. At the
time of publication of the 1986 proposed rule (51 FR 1092; January 9,
1986) for the revised standards for protection against radiation, the
Commission had proposed that only soluble materials be permitted for
disposal into sanitary sewers. The Commission received significant
comment at that time regarding the practice of research institutions to
use sewer disposal as the preferred alternative for disposal of tissue
samples over incineration. As a result, the May 21, 1991, final rule
allows readily dispersible biological material to be released but
prohibits the release of any non-biological insoluble material.
The Commission recognizes that new technologies for sewer treatment
are currently under development, such as the emerging mesocosm-based
treatments which use bioprocessors to neutralize sludge. These
bioprocessors can be selected with unique abilities to selectively
reconcentrate specific heavy metals and organics. In the consideration
of new requirements, the Commission invites comments on to what extent
and how the regulations should take into account the technologies for
processing sewage including technologies such as bioprocessing or ion-
exchange.
Coincident with publication of this advance notice, the Commission
has initiated contract support to analyze typical water treatment
processes, which includes determining how the solubility of materials
in influent to a treatment plant may be changed in a way that affects
the potential dose to members of the public. One possible outcome of
this analysis could result in modified restrictions regarding the forms
of materials suitable for disposal. Comments on the potential impacts
on licensee's operations associated with any additional restrictions
regarding the forms of materials suitable for dispersal are solicited.
(2) Total Quantity of Material
In the May 21, 1991, final rule, the Commission did not change the
total quantity of radioactive materials which could be released into
sanitary sewers. In brief, the limits are 185 GBq (5 Ci) of \3\H, 37
GBq (1 Ci) of \14\C, and 37 GBq (1 Ci) of all other radioactive
materials combined to be released into a sanitary sewer by a licensed
nuclear facility in a year provided the licensee complies with the
other requirements of 10 CFR 20.2003. The use of a total quantity limit
has been a long-standing requirement and was originally included to
address concerns regarding the possibility for reconcentration. The
Commission solicits comments regarding the acceptability of this
approach, and whether a total quantity to be released should be
specified or otherwise limited. As an alternative, the Commission
solicits comments on an approach which might limit the total quantity
of each radionuclide, such as some multiple of the annual limit of
intake values or the related exempt quantities published in 10 CFR part
30. This alternative approach could have the advantage of specifying a
total quantity limit, concentration and form requirement based upon the
biokinetics and health risk for each radionuclide. In particular, the
Commission solicits comments on the potential impacts on licensee's
operations associated with further restrictions on the total quantity
of radioactive material which could be released during a year.
The Commission also invites comments on whether the total quantity
of radionuclides that may be released to a sanitary sewer by a licensed
nuclear facility should take into consideration the capacity and
treatment methods used by the water treatment plant that serves the
licensee, and whether consideration should be given to the fact that
many licensed facilities may discharge into the same sewer treatment
plant. In this regard, the Commission is interested in comments on the
practicality of these approaches.
The NRC has also received a petition for rulemaking submitted by
the Northeast Ohio Regional Sewer District concerning the disposal of
radioactive material into sanitary sewerage (PRM-20-22). A notice of
receipt and request for comment on the petition was published in the
Federal Register on October 20, 1993 (58 FR 54071). The petitioner
requests that the NRC amend its regulations to require that all
licensees provide at least 24 hours advance notice to the appropriate
sewage treatment plant before releasing radioactive material to the
sanitary sewage system. The petitioner also requests that the NRC
exempt materials that enter the sanitary waste stream from the
requirements regarding Commission approval for incineration under the
NRC's current regulations. Comments on the issues raised in this
petition will be considered in any possible revision to NRC
regulations.
(3) Type of Limits
The present method of limiting releases into sanitary sewers is to
specify annual total quantity and concentration values of radioactive
materials. Table 3, Appendix B, of revised 10 CFR part 20 lists the
concentrations of radioactive materials which can be disposed of in
sanitary sewers and is based upon a calculated dose of 5 mSv/yr (500
mrem/yr) via ingestion of the effluent as the total water intake of the
individual (2 liters/day) at the point of release. These limits are
based upon a model of exposure which assumes that an individual could
be present at the sewer outfall of the licensee, and that the exposure
pathway is the ingestion of water. The Commission invites comments on
two facets related to this regulatory approach.
First, should the Commission continue an approach of limitation
based upon an individual being exposed by the ingestion of water from
the sewer outfall? Alternatively, should the Commission consider other
locations, such as at a treatment facility, in determining the level of
protection to be provided? If so, what modeling assumptions would be
appropriate? Further, how would these types of approaches deal with
exposure scenarios such as contamination in sewage sludges, as has been
the case in contamination incidents?
Second, should the Commission consider limitation using a dose
limit approach, and provide total quantity and concentration values in
a Regulatory Guide to facilitate compliance with the dose limit?
(4) Exemption of Patient Excreta
The present requirements exclude from sewer release limits the
contribution of patient excreta which may contain radioactive materials
as a result of nuclear medicine diagnosis or treatment. In general, the
radioactive materials used in these types of procedures have short
half-lives and decay rapidly after their production, use and subsequent
release into the sanitary sewer. Thus, doses to individuals from this
source are expected to be far below the NRC's dose limit for members of
the public. The Commission currently believes that the present
regulation is adequate but recognizes that radionuclides used in
nuclear medicine have been detected in very low concentrations on
occasion at treatment facilities. Therefore, the Commission invites
comments regarding the appropriateness of continuing the exemption for
patient excreta.
The preliminary views expressed in this notice may change in light
of comments received. In any case, there will be an opportunity later
for additional public comment in connection with any proposed rule that
may be developed by the Commission.
Case Studies
Case 1--Tonawanda, New York
A manufacturer of smoke detectors, which used Americium-241
(\241\Am) foils, operated in the 1970s and early 1980s in Tonawanda,
New York. When the facility was being decommissioned in 1983, \241\Am
contamination of the sewer lines leading from the facility was
detected. Similar contamination was subsequently detected in the STP
sewage sludge and incinerated sludge ash residue. It is believed that
the contamination occurred over a period of several years. Tests
performed by the State of New York in 1984 showed levels up to 27.75
Bq/g (750 pCi/g) of \241\Am in ash taken from a sludge incinerator.
Levels of 5.92 Bq/g (160 pCi/g) were detected in landfill samples. The
levels in the sludge at the time of the investigation were up to 3.7
Bq/g (100 pCi/g). Following the termination of licensed activities in
1983, these levels decreased to less than .037 Bq/g (1 pCi/g) by 1986.
Bioassays of STP workers and landfill workers detected no radioactivity
over background levels in their lungs or bones.
Case 2--Grand Island, New York
Because of the \241\Am contamination at the Tonawanda STP, the New
York Department of Health also collected sludge samples in 1984 at the
Grand Island STP, which received effluent from another manufacturer
that produced devices that used \3\H, \210\Po, and \241\Am. This
manufacturing facility discharged about 0.925 MBq/yr (25mCi/yr) of
\241\Am into the sanitary sewer that fed into the Grand Island STP. The
Grand Island STP uses tertiary treatment prior to discharging effluent,
with a sludge production averaging 450 ton/yr. Tertiary treatment
removes material from the effluent that has not been removed through
primary and secondary treatment. Tertiary treatment may include the use
of microscreens, filtration through specific media such as activated
charcoal, precipitation, and coagulation prior to discharging effluent.
The sludge is digested and pressed to increase the solids content to
about 20%, and it is subsequently buried in a landfill. The average
\241\Am concentration in the dry sludge was about 3.7 Bq/g (100 pCi/g)
dry weight when first studied. At the request of the New York State
Department of Labor, the manufacturer reduced the \241\Am concentration
in its liquid discharges after the contamination was identified. By
adding filtration to the licensee's holding tank, concentrations of
\241\Am in sludge were decreased to about 1.48 Bq/g (40 pCi/g). Using
information provided by the State of New York, calculations of the
annual average concentration of \241\Am in the wet sludge were based on
the assumption that all \241\Am entering the plant was concentrated in
the sludge. Wipe samples taken within the STP did not detect \241\Am
above levels allowed for unrestricted use (20 dpm/100cm\2\ removable
alpha contamination and 100 dpm/100cm\2\ total removable and fixed
alpha contamination). Some of the workers used dried sludge as a soil
supplement in their home gardens, and one garden showed measurable
amounts of \241\Am. Based on the sampling data, it was concluded that
there did not appear to be a radiation hazard to the STP employees or
landfill employees and that no specific safety measures beyond those
normally taken by employees would be required of these facilities.
Case 3--Royersford, Pennsylvania
A commercial laundry for radioactively contaminated protective
clothing discharged approximately 15,000 gallons of wastewater per day
to the local sanitary sewer system. The wastewater from the laundry was
temporarily stored, treated to adjust the pH, and analyzed for gross
alpha and gross beta activity before the contents were released to the
sanitary sewer system. Inspections by the NRC in late 1985 revealed no
violations by the licensee. Subsequently, an inspection of the
Royersford STP revealed radiation levels up to 12 Sv/h (1.2
mR/h) above background at the secondary digester. Because of these
elevated levels, the NRC evaluated the impacts of the radionuclides
released to the sanitary sewer system by the laundry facility. The
evaluation encompassed not only the STP, but the potential radiological
impact of sludge applications to agricultural areas as well. The
results indicated that the highest potential doses would be received by
farmers working the fields where the sludge had been applied. However,
potential doses were less than 50 Sv/yr (5 mrem/yr). Radiation
levels on the outside of a tank truck, used to carry the sludge to
application sites, ranged up to 3 Sv/h (0.3 mR/h), well within
the range allowed for transport by the Department of Transportation.
Case 4--Oak Ridge, Tennessee
A company in Oak Ridge which specialized in decontaminating nuclear
power plant materials disposed of a small amount of radioactive
material by release to the city sanitary sewer system. When a new STP
was put into operation by the city of Oak Ridge, contamination of the
sewer lines leading from the company was discovered. In addition,
radionuclides were detected in the sludge being processed at the sewage
treatment facility. The contamination was found at the STP in both its
primary and secondary digesters. This sludge had subsequently been
applied to deforested land at a government facility, resulting in
radiation levels of about 0.1 Sv/h (0.01 mR/h) (2 to 3 times
background) in the area. Stricter radioactive material release
guidelines were set by Tennessee's Division of Radiological Health, to
limit the amount of radioactive material released to the sewer system.
Additionally, the licensee was allowed to release only soluble
material, because it was suspected that some of the material previously
released had been insoluble.
A study was conducted by the State of Tennessee to evaluate the
risk to the general public from the radionuclides released into the
sanitary sewer systems at Oak Ridge and Erwin, Tennessee. The study
estimated that there were four radionuclides of concern in the sludge,
of which \137\Cs was the primary contaminant, with lesser quantities of
\60\Co, \134\Cs and \54\Mn. It was determined that the primary risk
would be through consumption of vegetables grown in a garden fertilized
with sludge from the STP at an estimated dose rate of approximately 60
Sv/yr (6 mrem/yr).
Case 5--Washington, DC
The Blue Plains Wastewater Treatment Plant processes waste from the
metropolitan Washington area, including a number of Federal research
facilities that use a relatively broad spectrum of radionuclides. Some
liquid effluents are released directly to the sanitary sewer system,
while others are retained in temporary holding tanks to permit decay of
short-lived isotopes before release. Inspections of two research
facilities and the STP were conducted in early 1986, with no violations
of Federal regulations or licenses noted. Samples were obtained at both
facilities from holding tanks and effluent discharge points and at the
STP for influent, liquid effluent, and sludge. Radionuclide
concentrations in facility effluents were 2% or less of the limits
specified for maximum daily release concentrations in Appendix B, Table
I, Column 2 of the version of 10 CFR part 20 in effect at that time.
Analysis of the STP samples revealed that concentrations of soluble
isotopes, such as \137\Cs and beta-emitters in general, were on the
same order of magnitude for liquid influent and effluent, and that
concentrations in sludge were about 10% of those in the liquid samples.
In contrast, for insoluble materials (primarily alpha-emitters), the
influent concentrations were about 10 times higher than those of the
liquid effluent samples.
Since the publication of the NUREG/CR-5814, additional incidents
concerning the reconcentration of radioactive isotopes in sewerage
sludge have been identified, and one is presented below.
Case 6--Cleveland, Ohio
During an aerial monitoring survey of an NRC licensee in the
Cleveland metropolitan area, \60\Co contamination was identified in a
STP that is part of the Northeast Ohio Regional Sewer District(NEORSD)
and services a large portion of Cuyahoga County. The source of the
radioactivity may have originated from a sealed source manufacturer
which had previously discharged to the STP. Analysis of treated
sewerage sludges samples revealed \60\Co concentration averages from
approximately 2.96 to 14.8 Bq/g (80 to 400 pCi/g). The STP is currently
proceeding to remediate the site. In October 1993, the NRC has received
two Requests for Modification of a License under 10 CFR 2.206 from
NEORSD. The first 2.206 Petition, notice of receipt published in the
Federal Register on April 13, 1993 (58 FR 19282), requested
modification to a license to require the licensee (1) to assume all
costs resulting from the off-site release of cobalt-60 that had been
deposited at a District treatment plant, and (2) to decontaminate the
sewer line connecting the licensee's facility and the District's
treatment plant. The second 2.206 Petition, notice of receipt published
in the Federal Register on December 6, 1993; 58 FR 64341, requested
modification to a license to require that the licensee provide adequate
financial assurance to cover public liability pursuant to section 170
of the Atomic Energy Act of 1954, as amended, 42 U.S.C. 2210. The NRC
is taking appropriate action on the two 2.206 Petitions as separate
matters.
List of Subjects in 10 CFR Part 20
Byproduct material, Criminal penalties, Licensed material, Nuclear
materials, Nuclear power plants and reactors, Occupational safety and
health, Packaging and containers, Radiation protection, Reporting and
recordkeeping requirements, Special nuclear material, Source material,
Waste treatment and disposal.
The authority citation for this document is: Sec. 161, 58 Stat.
948, as amended (42 U.S.C. 2201); Sec. 201, 88 Stat. 1242, as
amended (42 U.S.C. 5841).
Dated at Rockville, MD, this 18th day of February, 1994.
For the Nuclear Regulatory Commission.
Samuel J. Chilk,
Secretary of the Commission.
[FR Doc. 94-4294 Filed 2-24-94; 8:45 am]
BILLING CODE 7590-01-P
