Information Notice 2006-13, E-mail from M. Mclaughlin on NRC, Regarding NRC Information Notice 2006-13: Groundwater Contamination
| ML063000364 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 07/13/2006 |
| From: | Marjorie Mclaughlin Division of Nuclear Materials Safety I |
| To: | State of NY, Dept of Environmental Conservation, State of NY, Dept of Health, State of NY, Energy Research & Development Authority |
| References | |
| FOIA/PA-2006-0314, FOIA/PA-2009-0077, IN-06-013 | |
| Download: ML063000364 (9) | |
Marjorie McLaughin -NRC Information Notice 2006-13: Groundwater Contamination Pagje 1 I J
From: Marjorie McLaughlin "
To: Alp@nyserda.org; Asa01 @health.state.ny.us; bayoungb@gw.dec.state.ny.us;
jps@ nyserda.org; Igeorge@sni.org; Paul-eddy@dps.state.ny.us; Pjk3@westchestergov.com
Date: 07/13/2006 1:35:15 PM
Subject: NRC Information Notice 2006-13: Groundwater Contamination
Good Afternoon:
I am one of the two new Regional State Liaison Officers with the U.S. Nuclear Regulatory Commission's
(NRC's) Region I office. This email is being sent to inform you of an Information Notice (IN) that NRC
issued on Tuesday, July 11, 2006. Information Notices are issued to addressees to provide significant, recently-identified information about safety, safeguards, or environmental issues.
Addressees
are
expected to review the information for applicability to their facilities and consider actions, as appropriate, to
avoid similar problems.
IN 2006-13, "Groundwater Contamination due to Undetected Leakage of Radioactive Water," was
addressed to all holders of operating licenses for nuclear power, research, and test reactors (including
those who have permanently ceased operations). The IN was sent to inform these addressees of the
occurrences of radioactive groundwater contamination events at multiple facilities due to undetected
leakage from facility structures, systems, or components that contain or transport radioactive fluids.
This IN may be of particular interest to you because it describes the recent groundwater contamination
events at the Indian Point Nuclear Generating Station, as well as at other reactor sites. It was, therefore, felt that you would appreciate being notified of its issuance.
A copy of the IN is attached to this email. It is also available on the NRC Public Website at:
http://www.nrc.gov/reactors/operating/ops-experience/qrndwtr-contam-tritium.html. The ADAMS
Accession Number is: ML060540038.
If you have any questions on this or other issues, please call me. My contact information follows, Regards, Marjorie McLaughlin
Health Physicist
USNRC Region I Decommissioning
610-337-5240 (Phone)
610-337-5269 (Fax)
CC: David Lew; John White; Thomas Setzer
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555-0001 July 10, 2006 NRC INFORMATION NOTICE 2006-13: GROUND-WATER CONTAMINATION DUE TO
UNDETECTED LEAKAGE OF RADIOACTIVE
WATER
ADDRESSEES
All holders of operating licenses for nuclear power and research and test reactors including
those who have permanently ceased operations and have certified that fuel has been
permanently removed from the reactor and those authorized by Title 10 of the Code of Federal
Regulations (10 CFR) Part 72 licenses to store spent fuel in water-filled structures.
PURPOSE
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice (IN) to inform
addressees of the occurrence of radioactive contamination of ground water at multiple facilities
due to undetected leakage from facility structures, systems, or components that contain or
transport radioactive fluids. It is expected that recipients will review the information for
applicability to their facilities and consider actions, as appropriate, to avoid similar problems.
However, suggestions contained in this IN are not NRC requirements; therefore, no specific
action or written response is required.
DESCRIPTION OF CIRCUMSTANCES
Radioactive contamination of ground water has occurred at multiple facilities due to undetected
leakage from facility structures, systems, or components that contain or transport radioactive
fluids. Specific instances that have occurred recently include the following:
Braidwood Nuclear Power Plant
In March 2005, the licensee was notified by the Illinois Environmental Protection Agency (EPA)
of tritium detected in a nearby residential well. Following that notification, the licensee began
monitoring ground water between the community and the Braidwood plant. The licensee found
detectable levels of tritium in a drainage ditch near the Braidwood access road, but at that time, no other offsite contaminated ground water was found. Based on the tritium identified in the
drainage ditch, the licensee installed additional onsite monitoring wells to identify the source of
the tritium contamination.
In November 2005, the licensee identified peak contaminated ground water levels of
58,000 picocuries per liter (pCi/L) in shallow, ground-water monitoring wells located at the edge
of the owner controlled area. The licensee notified the NRC and immediately suspended all
further liquid radioactive releases. The tritium was attributed to historical leakage from vacuum
breakers along the circulating water system blowdown line that is routinely used for radioactive
liquid releases.
Although the Braidwood piping was below ground, the vacuum breaker valve vaults
communicate with the surface. Consequently, the leaks were both above and below ground.
The licensee subsequently determined that onsite radioactive leakage from the blowdown
system had occurred in 1996 (250,000 gallons), in 1998 (3,000,000 gallons), and in 2000
(3,000,000 gallons). Onsite tritium levels measured in a deep onsite ground-water monitoring
well measured as high as 282,000 pCi/L. Offsite tritium levels measured up to 1,600 pCi/L in a
residential well, below the Federal EPA drinking water standard of 20,000 pCi/L. The licensee
characterized the extent and magnitude of the tritium ground-water contamination as an area
that extended about 2,000 feet by 2,500 feet outside the site boundary. The licensee's
radiological assessment for the hypothetical, maximally exposed individual indicates that the
dose consequence would be about 0.16 millirem per year (i.e., about 5 percent of the "as low as
reasonably achievable" (ALARA) criteria for nuclear plant design objectives and limiting
conditions for operation).
The NRC inspection found that the licensee did not (1) adequately evaluate the radiological
hazards associated with the leakage; (2) calculate dose to member(s) of the public; (3) revise
its environmental monitoring program to adequately measure the impact to the environment;
(4) report aspects of the leakage in its annual effluent report; and (5) record the residual
contamination in files for decommissioning purposes (NRC Inspection Reports Nos. 50-456;
457/2006-02, Agency Wide Documents Access and Management System (ADAMS) Accession
No. ML061360416, and 50-456; 457/2006-008, ADAMS Accession No. ML 061450522).
Byron Nuclear Power Plant
Following the identification of tritium leakage at Braidwood, the licensee initiated a sampling
and analysis program along the Byron circulating water system blowdown line. Similar to the
Braidwood facility, the Byron blowdown line has six vacuum breakers located in valve vaults
located on plant property. Standing water in the vaults was sampled and analyzed, with five of
the six vaults having detectable levels of tritium up to 80,000 pCi/L. The licensee suspended all
radioactive liquid effluent releases through the blowdown line.
Residential wells were sampled and found not to have any detectable contamination. Additional
monitoring wells were installed near the valve vaults and detectable levels of tritium have been
found near two of the valve vaults. By April 2006, the licensee had completed repairs to the
vacuum breakers and vaults, including sealing the vault floors. After repairs were completed, the licensee recommenced liquid effluent discharges through the circulating water system
blowdown line (NRC Preliminary Notifications Nos. PNO-III-06-004 and PNO-III-06-004B).
Dresden Nuclear Power Station
In August 2004, the licensee identified contaminated ground water in onsite monitoring wells
resulting from a leaking underground pipe connected to the condensate storage tanks.
Subsequent, onsite sampling identified tritium levels consistent with those present in the
condensate storage tank of about 8,000,000 pCi/L. The licensee isolated the leaking pipe and
replaced the faulty section of piping.
Following the 2004 leak, the licensee sampled the private wells of nearby residents. One of the
residents' wells that had shown detectable tritium for a number of years had tritium levels of
approximately 1,000 pCi/L. Additionally, three other residential wells were found to have measurable but lower levels of
tritium. The licensee continues to evaluate the tritium in those wells, one of which is the normal
sample point for its radiological environmental monitoring program.
In February 2006, tritium levels of 600,000 pCi/L were detected in an onsite monitoring well
near a section of underground piping that had not been replaced in 2004. The leaking pipe was
isolated and onsite tritium levels in the two closest onsite wells subsequently stabilized at
20,000 - 50,000 pCi/L (NRC Inspection Report Nos. 50-237; 239/2006-03, ADAMS Accession
No. ML061290091).
Haddam Neck Station (Connecticut Yankee Atomic Power Plant)
The Haddam Neck Station ceased operations about 10 years ago and is being
decommissioned under an approved NRC license termination plan (LTP). The licensee's
monitoring programs have not identified any offsite ground-water contamination associated with
plant operations.
An onsite ground-water monitoring program has been established and is being implemented in
support of the decommissioning. The licensee initially identified tritium, cobalt-60, cesium-1 37 and strontium-90 in the onsite ground water and/or soil samples. The licensee has removed a
large amount of soil and some bedrock, and backfilled the excavated areas with clean soil.
While the licensee has substantially reduced residual contamination levels, recent ground-water
sampling results have identified residual tritium up to 19,500 pCi/L, cesium-1 37 up to 12 pCVL
and strontium-90 up to 4.5 pCVL. The licensee has completed dose assessments for the
existing onsite ground-water contamination in accordance with the LTP. The dose
assessments indicate a dose contribution of less than 1 millirem per year due to the
ground-water contamination.
The NRC license termination requirement is that the all-pathways, total effective dose
equivalent to the average member of the critical group does not exceed the 10 CFR 20.1402 unrestricted release requirement of 25 millirem per year and the residual radioactivity has been
reduced to ALARA. This includes the soil exposure pathway, existing groundwater dose
contributions and future groundwater dose contributions. Additionally, the licensee must
comply with requirements by the State of Connecticut's Department of Environmental
Protection to meet the Federal EPA Maximum Contaminant Levels. The most recent NRC
onsite inspection is documented in NRC Inspection Report No. 50-213/2005-03, ADAMS
Accession No. ML060390475.
Indian Point Nuclear Generating Station Units 1. 2. and 3 In September 2005, the licensee identified leakage of contaminated water from cracks in the
Unit 2 spent fuel pool (SFP), and subsequently discovered tritium contaminated ground water, about 200,000 pCi/L, in a monitoring well located in the Unit 2 transformer yard. Upon
discovery of this condition, the licensee initiated extensive efforts to characterize the nature and
source of the ground-water contamination. Efforts included the installation of a series of
instrumented monitoring wells, comprehensive hydrological and geophysical assessment of the
site, engineering efforts to determine the source of contamination, and enhancements to onsite
and offsite radiological environmental monitoring.
Extensive efforts were also made by the licensee and NRC to keep members of the public and
interested local, state, and federal stakeholders informed of progress and developments in the
site characterization, and plans to effect resolution of the ground-water contamination. Onsite ground-water tritium concentrations have been measured as high as about
600,000 pCi/L in the immediate vicinity of the Unit 2 SFP. Strontium-90 contamination has also
been identified in ground water in the vicinity of the Unit 1 decommissioned facility which has
been in SAFSTOR since 1974. The current hydrological assessment indicates that ground
water is likely migrating into the Hudson River. A conservative radiological assessment for the
maximally exposed individual indicates that the dose consequence would be about 0.01 millirem
per year (i.e., about 0.1 percent of ALARA criteria for nuclear plant design objectives and
limiting conditions for operation).
NRC Inspection Report 50-247/2005-11, dated March 16, 2006 (ADAMS Accession No.
ML060750842), documented the results of an NRC special inspection that was conducted to
review and assess the events and circumstances in this case. While the inspection reached
important safety conclusions, significant licensee performance deficiencies were not identified.
However, NRC inspection activities are continuing to review the licensee efforts and progress to
support a final regulatory conclusion.
BACKGROUND
NRC requirements related to the radioactive liquid effluents include:
10 CFR 20.1301(a)(1) - requires that each licensee conduct operations so that the total
effective dose equivalent to individual members of the public from the licensed operation does
not exceed 100 millirem (1 mSv) in a year.
10 CFR 20.1302 - requires licensees to perform appropriate surveys in'unrestricted areas and
controlled areas to demonstrate compliance with dose limits for individual members of the
public.
10 CFR 20.1501 - requires, in part, that licensees conduct surveys that are reasonable under
the circumstances to evaluate the concentrations or quantities of radioactive material and the
potential radiological hazards.
10 CFR Part50, Appendix I,Section II.A - establishes the design objectives and limiting
conditions for operation to meet ALARA criteria such that the calculated annual total quantity of
all radioactive material above background released to unrestricted areas will not result in an
estimated annual dose or dose commitment from liquid effluents in excess of 3 millirems to the
total body or 10 millirems to any organ.
10 CFR Part50, Appendix A, Criterion 64 - requires, in part, that a means be provided for
monitoring effluent discharge paths, and the plant environs for radioactivity that may be
released from normal operations. To meet this regulation, licensees implement a Radiological
Environmental Monitoring Program (REMP) which provides for ground-water monitoring.
However, the REMP program is designed to validate the results of the licensee's normal
radioactive gaseous and liquid effluent release programs for dose assessment in the
Unrestricted Area. Consequently, the data from the REMP program may not provide a full
understanding of the extent, types, and movement of potentially undetected radioactive
contamination in onsite ground water within the Restricted Area. NRC Regulatory Issue
Summary 2002-02, "Lessons Learned Related to Recently Submitted Decommissioning Plans
and License Termination Plans," dated January 16, 2002, provides additional information in this
regard (ADAMS Accession No. ML013510432). 10 CFR 50.75(g)(1) - requires, in part, that each licensee keep a record of spills or other
unusual occurrences involving the spread of contamination in and around the facility or site.
These records must include any known information on identification of involved nuclides, quantities, forms, and concentrations. Such documentation in a decommissioning record file is
important to provide a database for site characterization during decommissioning, as well as, providing support for public and worker dose assessments. NUREG-1757, "Consolidated
[Office of Nuclear Material Safety and Safeguards] NMSS Decommissioning Guidance,"
provides guidance on decommissioning record keeping (ADAMS Accession No.
10 CFR 50.72 - requires a four-hour report to NRC Operations Center when any event or
situation occurs, related to protection of the environment, for which a news release or
notification to other government agencies has been or will be made.
Related Generic Communications
NRC Information Notice 2004-05, "Spent Fuel Pool Leakage to Onsite Ground Water," dated
March 3, 2004, (ADAMS Accession No. ML040580454) discussed SFP leakage at Salem
Station Unit 1 to the onsite ground water, including potential impact to the public and workers, and the structural integrity of the SFP. The NRC noted that leaks can develop in SFPs and go
undetected for long periods of time absent appropriate monitoring, resulting in the
contamination of onsite ground water and the potential for undetected, unevaluated releases of
radioactivity to an unrestricted area.
DISCUSSION
NRC',"reviews to-date have identified the following important points associated with
ground-water contamination events:
1. Leakage from structures, systems, or components that contain and transport radioactive
fluids can contribute, over long periods of time, to extensive ground-water
contamination. This leakage may not be easily detectable due to small leakage rates or
because the area near the point of leakage is not subject to routine radiological
monitoring. Leakage from underground piping at Braidwood released substantial
quantities of contaminated water to onsite ground water. Representative sampling and
analysis of onsite ground water may be the only viable method to detect this leakage
and the subsequent migration of the contamination, particularly for subsurface leakage
(e.g., buried pipe leakage).
2. Existing NRC regulations do not explicitly mandate routine onsite ground-water
monitoring in the Restricted Area during facility operations. If the contamination is
detected by environmental monitoring at or beyond the site boundary under the REMP,
extensive contamination may have already occurred that could have been contained if
detected sooner. Further, although licensees may be sampling onsite drinking water as part of its REMP, this water may originate from deeper hydro-geologic units not affected
by contamination of the shallow water table hydro-geologic unit.
3. The identification of onsite contamination may serve as an early indicator of degradation
of onsite structures, systems, or components or the need for maintenance, particularly
degradation caused by boric acid.
4. The principal screening method of detecting leakage at reactor sites is sampling and
analyses for tritium contamination. However, other analysis methods can detect
radioactive gamma emitters, and consideration should be given to performing analyses
for typical hard-to-detect radionuclides. These nuclides can consist of both fission or
activation products that may include Nickel-63, Iron-55, Strontium-90, transuranics, and
others. While initial analyses may conclude the absence of gamma emitters and hard- to-detect radionuclides, long-term migration may subsequently result in the transport of
contamination to downstream locations. Further, a working knowledge and
understanding of onsite hydrology would aid development of monitoring strategies, sampling plans, and selection of individual sampling locations.
5. Licensees typically establish onsite ground-water monitoring and sampling programs in
response to known, identified structure, system, or component leakage. Once the
source of the leakage is repaired, it is important to objectively evaluate whether it is
appropriate to terminate these supplemental onsite monitoring and sampling programs, as the onsite monitoring and sampling programs may be the only reliable method for
detecting repeat occurrences in a timely manner, particularly for subsurface leakage. In
the case of the Dresden facility, the onsite ground-water monitoring wells that had been
installed for previous leakage incidents were instrumental in identifying the 2006 leakage, which enabled a more timely identification and limited the extent of the
contamination.
6. SFP leak detection may require special techniques since SFPs have an evaporation rate
up to several hundred gallons per day. This evaporation rate may mask small leaks in
the SFP liner and make' small leakage rates difficult to detect by evaluation of make-up
rates within a water balance calculation. Consequently, licensees who are not closely
evaluating the potential for leakage, including through-wall and/or floor leakage, may not
detect such leakage. Further, the leakage may be from SFP fuel transfer tubes and
may only occur during refueling outages. Because there is considerable water transfer
activity during refueling outages, small leakage rates may not be readily apparent during
make-up or transfer operations. Other considerations include:
Licensee experience with onsite and offsite ground-water contamination as a
result of SFP leakage varies significantly. Some licensees have identified large
areas of onsite ground-water contamination due to SFP leakage. It is important
to be aware that small, long-term, undetected leaks from SFPs can result in
extensive areas of contamination.
Due to the difficulty in detecting single small leaks or small leaks from different
locations, particularly those that occur over long time periods, corrective actions
may involve management of leakage (e.g., collection and treatment) rather than
leak repair.
Some licensees have not evaluated the capability of their SFP leak detection
systems to detect small leaks. Leakage trending and tracking programs can
I*
- i supplement leakage detection systems and provide an indication of changes in
apparent leakage rates. Any unexplained change in leakage rates, including a
reduction in leakage rates, should prompt further evaluation.
Clogging of SFP telltale drain systems could result in undetected SFP leakage.
Maintenance and cleaning programs for SFP telltale drain systems ensure viable
drain paths remain open. Alternate methods to look for leakage are available for
facilities without SFP telltale drain systems.
7. Leakage from facility structures to the environment can itself become a source of
contaminated in-leakage (back into the facility) at another location. Because stations
have facilities and rooms below grade level, it is not uncommon for ground water to leak
into the facilities. It is important to evaluate unexpected in-leakage to determine if it is
contaminated ground water using radio-analytical and chemical analysis (e.g., boron).
8. Radioactive contamination of subsurface rock, soil, or ground-water contamination can
impact decommissioning decisions. Remediation at the time of discovery in some
instances could prevent significant migration to large subsurface areas that could
complicate and increase the cost of decommissioning. Hydrogeology studies and the
addition of onsite monitoring wells should be considered to identify ground-water flow
patterns, support knowledge of the location and extent of contamination, to quantify
contaminant migration, and to support decision-making for potential remediation
measures. These studies can also support an estimation of future decommissioning
costs.
9. NRC's inspection program identified that there is an apparent wide variation in licensee
- . knowledge in the requirement to document the ground-water contamination issues
consistent with all parts of 10 CFR 50.75(g)(1) for the decommissioning record file.
Such documentation is important to provide a database for site characterization during
decommissioning, as well as, providing support for public and worker dose
assessments.
CONCLUSION
Although NRC regulations require licensees to make surveys, as necessary, to evaluate the
potential hazard of radioactive material released in order to assess doses to members of the
public and workers, the above examples indicate that undetected leakage to ground water from
facility structures, systems, or components can occur; resulting in unmonitored and unassessed
exposure pathways to members of the public.
GENERIC IMPLICATIONS
This information notice provides a timely means of communicating to licensee senior
management information regarding ground-water contamination. To address this important
issue, NRC is actively pursuing rulemaking to revise 10 CFR 20.1406, "minimization of
contamination," and its supporting guidance, as well as changes to NRC inspection and
enforcement guidance. These ongoing NRC efforts are part of the NRC's Integrated
Decommissioning Improvements Plan (ADAMS Accession No. ML050890059) to resolve issues
described in SECY-03-0069, "Results of the License Termination Rule Analysis" and its staff requirements (ADAMS Accession Nos. ML030840302 and ML033210595). A publically
available NRC memorandum dated September 23, 2005, provides the results of an initial NRC
study of ground-water contamination at decommissioning sites (ADAMS Accession No.
CONTACT
This information notice requires no specific action or written response. If there are any
questions about this notice, contact one of the persons listed below or the appropriate project
manager in the Office of Nuclear Reactor Regulation (NRR) or Office of Nuclear Material Safety
and Safeguards.
Charles L. Miller, Director Ho K. Nieh, Acting Director
Division of Industrial and Medical Nuclear Safety Division of Policy and Rulemaking
Office of Nuclear Material Safety Office of Nuclear Reactor Regulation
and Safeguards
Technical Contacts:
Timothy Frye, NRR Marvin Mendonca, NRR
301-415-9676 301-415-2191 E-mail: tif(cnrc.oov E-mail: mmm(onrc.gov
John White, RI James Shepherd, NMSS
610-337-5114 301-415-6712 E-mail: irwl(,nrc.qov E-mail: ics2(nrc..ov
Steve Orth, RIll Thomas Nicholson, RES
630-829-9827 301-415-6268 E-mail: sko(cnrc.qov E-mail: tin(cnrc.aov
Ronald Nimitz, RI
610-337-5267 E-mail: rln(anrc..ov