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On-Site Ground Water Monitoring

This section reviews: (1) leaks of radioactive liquid into the ground from buried components; (2) why buried components corrode; (3) Pilgrim’s onsite groundwater monitoring program and why it is insufficient; Tritium


Leaks of radioactive contaminated liquid into the ground from buried components at U.S. nuclear reactors have occurred with increased frequency. Many of these leaks were initially undetected and remained undetected for many years. In at least one case, the leak was not detected until after an underground plume of several million gallons of contaminated water traveled beyond the nuclear facility's site into drinking wells. In most cases, the leak was finally detected more by happenstance than by rigorous monitoring. In all cases, a small leak undetected for an extended period of time permitted large amounts of contaminated water to enter the ground around the facilities.

Better prevention and monitoring systems are needed. Unmonitored leaks of radioactive materials offsite are against NRC regulation; a public health hazard; a threat to local fishing and aquaculture; and may significantly increase the monies needed to decommission the reactor beyond what the owner set aside, sticking added costs to citizens.

A list of tritium leaks compiled by the Burlington Free Press - Tritium leaks a problem at many plants –(January 24, 2010) included:  Massachusetts:  Pilgrim, Rowe,; Arizona: Palo Verde; Connecticut: Connecticut Yankee (Haddam Neck); Delaware: Salem; Georgia: Hatch; Kansas: Wolf Creek; Illinois: Braidwood, Byron, Dresden; Missouri: Callaway; New Hampshire: Seabrook New Jersey: Oyster Creek; New York: Indian Point 1 and 2); Ohio: Perry; Pennsylvania: Three Mile Island, Peach Bottom; Tennessee: Watts Bar Vermont: Vermont Yankee; and Wisconsin: Point Beach. 

There is little reason to believe this is an unabridged listing of nuclear facilities experiencing leakages of contaminated water. It seems entirely possible, if not highly likely, that more nuclear facilities have an ongoing leak that has yet to be detected. Further it is important to recognize that dangerous radioisotopes have leaked, in addition to tritium. 

Corrosion- causes

Material: Buried pipes and tanks are made of metals – all metals corrode.

Water & Moisture: It is basic that water and moisture are needed for external corrosion to occur. They deteriorate the components outside coating and wraps.

Cathodic Depolarizers: When moisture is present and the coating then deteriorates, one needs additionally a cathodic depolarizer to further the cathodic reaction in order of corrosion to occur. This may be oxygen, certain microorganisms (bacteria, algae, fungi) or low pH generated by acid rain or the increased salinity of the ocean due to pollution; or the chloride ion (CI).

Bath-Tub Curve Aging: The rate of corrosion is not linear over time. Even the most meticulously maintained systems, like the Space Shuttles, which are a much newer engineered technology than Pilgrim, are reaching the end of their useful life due to the aging phenomena of the Bathtub Curve.” The Bathtub curve is described in U.S. Nuclear Plants in the 21st Century: The Risk of a Lifetime, by David Lochbaum, Union of Concerned Scientists, (May 2004)  The chances of failure occur at the very beginning when "kinks" are worked out; followed by a period of little difficulty during the middle years; and then the "wear-out" phase follows as parts age. The license renewal period of a nuclear plant is in the "wear-out" phase after 40 years of operations. According to the Union of Concerned Scientists' report,  “As reactors approach or enter the wear-out phase and become more vulnerable to failure, aging management programs should monitor the condition of the equipment and structures more frequently so as to affect repairs or replacements before minimum safety margins are compromised. Unfortunately, age-related degradation is being found too often by failures than by condition-monitoring activities.”

Stray currents: Additionally underground corrosion is amplified by stray currents which are present in one degree or another at power generating stations.

Sand/Soil Particles:
Sand and soil particles move in the subsurface and are abrasive; if the pipes are initially packed in a sand bed and/or the soils are sandy, silt and clay then abrasion is likely to occur.

Thermal Variations & Lineal Expansion: Thermal variations result in stress. If the outside soil temperature is markedly colder than the temperature of the liquid inside the pipe or tank, the exterior pipe wall will contract on the outside and expand on the inside. Conversely, if the liquid inside freezes and then expands stress will result potentially leading to cracks. In either situation, over time the metal would crack and break just as a paper clip eventually snaps from bending it back and forth.

Elbows & Welds: Straight piping is less susceptible to failure than welds, elbows and dead spots.

Counterfeit or Substandard Pipes: A 1990 United States Government Accounting Office Report  identified widespread use of counterfeit parts in the industry. Pipe fittings and flanges were among the parts listed. Pilgrim, for example, was among those reactors listed with substandard or counterfeit parts. The use of counterfeit parts destroys the validity of NRC risk assessments and assurances of safety. (United States General Accounting Office, Report to the Chairman, GAO/RCED-91-6, October 1990)

Manufacturing, installation, Excavation Errors: Human error cannot be discounted.


pilgrim plant

Pilgrim is adjacent to Cape Cod Bay. Radioactive leaks from buried components may end up in the water threatening public health, by entering the food chain or washing ashore to our beaches to then become airborne; and threatening our fishing and aquaculture industries. Pilgrim’s site specific environment is corrosive and the majority of its piping is old. To provide the protection our communities deserve, Pilgrim’s aging management program for buried components should entail a sufficient number of monitoring wells placed according to accepted design; cathodic protection to prevent corrosion; and a robust inspection program.
At present, nobody knows what has leaked already or will leak in the future. We are at risk. But the attitude of the industry appears best captured in the Simpsons. Homer: (about Blinky) “Oh, Marge, what's the big deal? I bet before the papers blew this out of proportion, you didn't even know how many eyes a fish had.” 

What’s wrong?

Monitoring Wells: Tritium, from a yet identified source, was found in samples immediately after Pilgrim installed four (4) monitoring wells as part of its November 2007 voluntary well monitoring program.   However, Pilgrim’s voluntary wells do not meet accepted design criteria, and thus do not provide reasonable assurance.  Four wells may be suitable for a corner service station, but not for a nuclear reactor on the shores of Cape Cod Bay.

During Pilgrim’s license renewal adjudication process, Pilgrim Watch’s expert, Dr. David Ahlfeld PhD, PE, Professor, Department of Civil and Environmental Engineering, University of Massachusetts evaluated Pilgrim’s onsite monitoring well program and found it to be insufficient.  He said that,

"Recently, Entergy reported finding tritium at levels up to about 3000 pCi/L in monitoring wells on site. [November 2007] These initial monitoring results highlight flaws in the monitoring system at PNPS and provide a contrast to appropriate monitoring design. 

Based on the map provided by Entergy in its recent filing, four monitoring wells have been placed at the site.  These are generally located between the reactor and the shoreline.  The wells are spaced approximately 200 feet apart.  I am not aware of any recent hydrogeologic studies that have been conducted to determine current groundwater flow directions and rates.  Hence, the suitability of these wells to actually intercept plausible leakage transport pathways is unknown. Based on my estimation of the locations of pipe runs and plausible leak locations, this number of wells is entirely inadequate to provide the assurance of detection called for in the NEI guidance and in industry practice.  Given the short distance from likely pipe locations and the shore, it is highly likely that a leak of radiological contaminants could migrate through the groundwater and pass between these widely-spaced wells or perhaps flow beneath them without detection.  

It is useful to contrast the PNPS' plan with Entergy’s Indian Point NPS which has many times more monitoring wells.  Indeed, a 4-well monitoring system is more typical of that used for a retail gasoline station or a small municipal (non-hazardous) landfill.  That it should be considered adequate for a large industrial facility such as PNPS is unrealistic. The selection of tritium as the indicator contaminant raises a problem since tritium may be present in several of the potential leak sources that are within scope (e.g. condensate storage tank and salt service water systems).  Hence, tritium does not provide a unique indicator of the component which is the source of the leak.  A better designed monitoring system would seek a range of radionuclides that, taken together, serve as specific source indicators.

Presuming that the tritium detected originated at PNPS, the question arises as to the specific mechanism by which this tritium came to be at, for example, well MW 201.  It has been suggested by PNPS personnel, as reported in the press, that this tritium is from rainfall sources.  Presumably, the transport pathway for this would be airborne tritium captured by passing raindrops with rainfall subsequently infiltrating to the subsurface.  But this transport pathway may be limited if, as is presumably the case, the monitoring wells are placed in a paved area of the site where rainfall cannot infiltrate.  There are alternative theories for the source of tritium.  A small pipe leak producing a transported plume of tritium that happens to travel near to monitoring well MW 201 might account for the observed levels of tritium.  Alternately, a larger pipe leak producing a large plume of tritium with concentrations much larger than 3000 pCi/L might exist in the subsurface between wells MW 201 and MW 202.  In this scenario, the diluted edge of the plume happens to travel near to monitoring wells MW 201 and MW 202.  These alternate hypotheses highlight the fact that with so few monitoring wells, it is impossible to determine with any degree of certainty what contaminants may exist in the subsurface.

In summary, groundwater monitoring networks can be used as part of a leak detection system and are widely used for this purpose.  Well-established protocols exist for proper design of monitoring networks including well and screen placement, sampling frequency and selection of sampled contaminants.  The 4-well monitoring system apparently used by Entergy does not meet reasonable standards for monitoring network design."


Entergy’s (2) Additional Wells: We understand that Entergy added two, already-existing, monitoring wells to their groundwater program. Based on information provided by Entergy’s Jack Alexander to the Plymouth Nuclear Affairs Committee (January 20, 2010) it seems clear that these can serve, at best, as control wells. One (identified as WWTP MW-3) is located near the transformer. However, there are 3 transformers located outside of the Turbine building. They are the Main, Unit Auxiliary and the shutdown transformers.  There is also a transformer known called the Startup transformer located in the far side of the switchyard.  All are oil filled and we understand have leaked oil over the years into the ground around them – hence the well.  Further we understand that these transformers are not in contact with any radioactive material.  Also, there is a unit known as the 24KV Switch located on Rocky Hill Road across from the entrance to the shorefront.  Precisely where is WWTP MW-3 located?  The other well (XFMR-MW4) is located somewhere near Rocky Hill Rd., placed to monitor potential leakage of human wastes into the sewer system. Again, precisely where is this well located? We request that the department provide a map showing the placement of all groundwater monitoring wells.

To summarize, Entergy’s monitoring well program is insufficient because:

Number Wells: The number of wells (6) are totally inadequate for a large and aging nuclear reactor facility – (3) potential indicator wells and (3) control wells.

Placement: The placement of the system does not meet standard well design.

Analysis:  We understand that the groundwater samples will be analyzed for gamma-emitting nuclides (Mn-54, Fe-59, Co-58, Co-60, Zn-65, Zr-95, Nb-95, I-131, Cs-134, Cs-137, Ba-140 and La-140) per the Off-site Dose Calculation Manual (ODCM)/ Radiological Environmental Monitoring Program (REMP).  The lower limit of detection as specified in the REMP for the above listed isotopes ranges from 15 to 60 pico-Curies per Liter (pCi/L).  Tritium analyses will also be performed on all groundwater samples.  The samples will be analyzed to exclude interferences and the lower limit of detection for tritium will be at a value at or below the federal requirements dictated in the Radiological Environmental Monitoring Program (REMP), typically 2000 pCi/L.

According to NRC's Groundwater Contamination at Nuclear Plants Task Force, Final Report, September 1, 2006, limiting analysis to gamma particles would miss radionuclides significant to public health and does not suit today’s waste streams and technology. We understand from NRC documents that today, as a result of better fuel performance, and improved radioactive source -term reduction programs that the new liquid radioactive effluent source term is made up of a lower fraction of gamma emitting radionuclides and a higher fraction of beta emitters. Therefore, analysis also should include beta and alpha particles.   At minimum, Entergy should specifically analyze for strontium-90, tritium, cobalt-160, cesium-137 and transuranics.  For example, at Vermont Yankee, Indian Point, and Connecticut Yankee other harmful and longer-lived isotopes such as strontium-90 and cobalt-60 were discovered.

The limits of detection should be lowered. We understand by reading the NRC Task Force Report that  many licensees, now, have enhanced detection capability and routinely analyze environmental samples at much lower radioactivity levels than required by regulatory guidance and license conditions. We expect that Entergy, too, is in the forefront now.

We also understand that it will require pressure from the public and our elected and appointed officials, such as MDPH, to enhance Entergy’s testing protocol. However, MDPH currently takes split samples; therefore there is no reason that the department must be limited to Entergy’s protocol. We believe it is reasonable to expect the department to analyze for other isotopes listed above that are of health significance.

Reference: The NRC’s Groundwater Contamination at Nuclear Plants Task Force, Final Report, September 1, 2006 noted that, (1)The radiological effluent and environmental monitoring program requirements and guidance largely reflect radioactive waste streams that were typically from nuclear plant operation in the 1970s. The issues that were important then, i.e. principal gamma emitters giving the significant dose, while still important today, have been joined by new issues. Today, as a result of better fuel performance, and improved radioactive source term reduction programs, a new radioactive waste source term has evolved. The new liquid radioactive effluent source term is made up of a lower fraction of gamma emitting radionuclides and a higher fraction of weak beta emitters” (page 21). For example, experience at Connecticut Yankee and Indian Point and others shows Sr-90 (beta) and Cs-137 (beta) of significance. (2)“The radiation detection capabilities specified in the BTP are the 1970s state-of-the-art for routine environmental measurements in laboratories. More sensitive radiation detection capability exists today, but there is no regulatory requirement for plants to have this equipment. As a practical matter, many licensees so have the enhanced detection capability and routinely analyze environmental samples at much lower radioactivity levels than required by the regulatory guidance and license conditions. This capability has provided increased precision in quantifying the typically small doses attributed to any abnormal releases.” NRC’s Groundwater Contamination at Nuclear Plants Task Force, Final Report, September 1, 2006, page 18.

Reports:  We understand that Entergy plans to report the results of the groundwater analysis in the Annual Radioactive Effluent Release Report (REMP); and if detectable levels of tritium or gamma-emitters are found, Entergy will notify key stakeholders in the vicinity of the plant and inform them of the situation and our plans for addressing it. Duxbury believes that reports should be made as close to lower limit detection. Entergy’s Jack Alexander opined January 20, 2010 that background for tritium is 200 pc/L; therefore it seems reasonable that the notification limit should be 800-1000 pc/l. We requested that MDPH place on its website a complete report of findings after each analysis is completed; and that the department includes in its report test results for nuclides in addition to tritium.

Cathodic Protection: Pilgrim, unlike some nuclear plants, does not have cathodic protection - a technique to control corrosion of a metal surface by placing a sacrificial piece of metal nearby. It is commonly used to protect steel, water or fuel pipelines and storage tanks, steel pier piles, ships, offshore oil platforms.

NRC Inspection Program: The required inspections are too infrequent, once during the (10) years prior to license renewal and once during the first (10) years of license renewal (2012-2022); and the required inspections do not specify the location or length of the component that must be inspected. In response to the proliferation of leaks at reactors the NRC instead of requiring more robust inspections deferred to industry’s wishes and allowed a voluntary industry program. Entergy’s voluntary program is called the Buried Piping and Tanks Inspection Program and Monitoring Program (BPTIMP). According to NRC’s recent document, SECY-09-0174, “The staff may perform audits and/or develop a TI to evaluate licensee implementation of the Buried Piping Integrity industry initiative” [Emphasis added].

To read Entergy’s Buried Pipes and Tanks Inspection Program please see Pilgrim Watch Presents Statements of Position, Direct Testimony and Exhibits Under 10 C.F.R. 2.1207, NRC Electronic Library, ADAMS “ML 080320605.” Entergy’s BPTIMP is Exhibit No. 5 at page 190; Pilgrim Watch’s Expert’s critique of the program is Exhibit 1, Arnold Gundersen’s Support of Pilgrim watch’s Contention 1, beginning on page 106.

Routine Maintenance: The large number of reported groundwater leaks around the country belies the effectiveness of routine maintenance to prevent leaks. Again see Pilgrim Watch Presents Statements of Position, Direct Testimony and Exhibits Under 10 C.F.R. 2.1207, NRC Electronic Library, ADAMS “ML 080320605.” Pilgrim Watch’s Expert’s critique of the program is Exhibit 1, Arnold Gundersen’s Support of Pilgrim Watch’s Contention 1.


Congress: Representative Edward Markey (D-Mass.), Chairman of the Energy and Environment Subcommittee, Rep. John Hall (D-N.Y.), and Rep. John Adler (D-N.J.) sent a letter January 13, 2010 to the Government Accountability Office (GAO) requesting an investigation into the integrity, safety, inspection, maintenance, regulations and enforcement issues surrounding buried piping at our nation’s nuclear power plants. The letter to the GAO was prompted by a rash of recent failures in the buried piping systems of nuclear reactors. Congressman Markey’s press release said that, “These pipes serve critical functions within power plants.  In some cases, these buried pipes carry the water which would cool the reactor core in the event of an unexpected plant shut-down.  In other cases, the pipes carry diesel fuel to emergency generators. Despite the critical importance of these pipes, most have never been inspected. After decades underground, neither the NRC nor the plant operators can be absolutely certain that the pipes are intact.”  And, “Under current regulations, miles and miles of buried pipes within nuclear reactors have never been inspected and will likely never be inspected…This is simply unacceptable.  As it stands, the NRC requires – at most – a single, spot inspection of the buried piping systems no more than once every 10 years. This cannot possibly be sufficient to ensure the safety of both the public and the plant.”

A copy of the letter can be found here

NRC: NRC Chairman Gregory B. Jaczko (September 3, 2009) directed the agency’s technical staff to review the NRC’s approach for overseeing buried pipes given recent incidents of leaking buried pipes at several U.S. commercial nuclear power plants. On December 2, 2009, the NRC staff issued SECY-09-0174, a copy is available on NRC website at  Again on January 29, 2010, Chairman Jaczko remarked at a program briefing NRC Office of Nuclear Reactor Regulation (NRR) that, “NRC must stay focused on its core mission of ensuring the safety and security of existing reactors. We have a lot of work ahead of us. NRR faces some long-standing challenges and some really difficult issues. Those include buried piping, submerged cables, containment sump performance, and, of course, fire protection.”

States and Public Interest Groups: (NYS-5) New York State’s intervention in Indian Point’s License Renewal Application (LBP-08-13) contention 5 says that, “the Aging Management Plan contained in the license renewal application Violates 10 C.F.R. §§ 54.21 and 54.29(a) because it does not provide adequate inspection and monitoring for corrosion or leaks in all buried systems, structures, and components that may convey or contain radioactively contaminated water or other fluids and/or may be important for plant safety.” The hearing is expected summer, 2010, and all filings are in NRC’s electronic library, Adams.

Pilgrim Watch’s intervention in Pilgrim’s License Renewal Application contention 1 says that, “The Aging Management Plan does not adequately inspect and monitor for leaks in all systems and components that may contain radioactively contaminated water.” All filings are available in NRC’s electronic library, Adams. Please refer to “re-licensing” in this website.




[Source: Radioactive Rivers and Rain: Routine Releases of Tritiated Water From Nuclear Power Plants, Annie Makhijani and Arjun Makhijani, Ph.D. August 2009, ;Health Risks of Tritium: The Case for Strengthened Standards, Arjun Makhijani, Brice Smith,  Michael  C. Thorne, February 2007,]


Tritium, What Is It?

Tritium, a radioactive form of hydrogen, is a gas in its elemental form. Like ordinary hydrogen, tritium combines with oxygen to make water, called tritiated water. Tritiated water is radioactive. Tritiated water is chemically identical to normal water and the tritium cannot be filtered out of the water.

Where Does It Come From?

Natural: There is some natural background tritium in surface and groundwater that comes from the interaction of cosmic radiation with the atmosphere. These levels are very low – typically 5 to 25 picocuries per liter in surface water and less than 6.4 to 12.8 picocuries per liter in groundwater.[1]

Weapons: Large amounts were added in the atmosphere and global waters from atmospheric testing of nuclear weapons. However the last atmospheric test was by China in 1980; and since the half-life of tritium is 12.3 years, most of the additions due to testing have decayed away.

Nuclear Reactors: Nuclear reactors generate tritium in the course of their operation and release it both to the atmosphere and to water bodies.

Liquid Reactor Discharges: Tritium liquid releases have occurred as a result of malfunctions such as leaks from buried components – called unintended releases.

A 2006 NRC Information Notice explains (at 6) that,[2]


1. [These] leaks can contribute, over long periods of time, to extensive groundwater 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.


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 (Radiological Environmental Report), 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 and 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.   ...onsite monitoring and sampling programs may be the only reliable method for detecting repeat occurrences in a timely manner, particularly for subsurface leakage


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.



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.


Gaseous Reactor Discharges: In addition to liquid discharges, releases of tritiated water vapor from the stacks of nuclear power plants can result in radioactive rainfall, which can contaminate surface water bodies as well as groundwater.


Rainfall & Pilgrim Nuclear Power Plant’s (PNPS) Experiment:


Rainfall episodes that occur during gaseous discharge events result in the rainfall becoming contaminated with tritium. Such contamination could reach high levels under certain weather and tritium release conditions. Data for rainfall near reactors are not part of the Environmental Reports filed by nuclear power plant operators. The NRC does not require rainwater monitoring nor monitoring of groundwater and surface water that may be affected by contaminated rainfall events. NRC does not believe that separate pathway monitoring is necessary since the dose limits are below those required. However, this is flawed logic. If private groundwater sources and rainfall are not monitored, how can the NRC know that dose limits are not being exceeded, especially since high contamination events can occur and, under present dispensation, escape detection.

The possibility of contamination by rainfall was raised in a presentation made by Ken Sejkora, of Entergy Nuclear Northeast – Pilgrim Station, who has stated that “Localized washout can result in very high concentrations, possibly even exceeding drinking water standards.[3]” PNPS' Ken Sejkora currently is conducting rainfall experiments at Pilgrim Station.

One important question is the location of the control samples. Because, as Dr. Ian Fairlie said in his report, Tritium Hazard Report: Pollution and Radiation Risk from Canadian Nuclear Facilities, June 2007[4] (at 24),

It is important to know the true background concentration of airborne tritiated water vapor … so that we can deduct this value from observed values near nuclear stations to establish what concentrations are due to the discharges. The difficulty is that most tritium measurements are made near nuclear stations and one has to be very remote, at least >300 km (186.411 miles) away, in order to escape from low levels of tritium contamination from nuclear stations. Only a few tritium-in-air measurements are made very remote from nuclear facilities. [Emphasis added]


How Do People Become Exposed To Tritium?

Tritium is almost always found as a liquid and primarily enters the body when people eat or drink food or water containing tritium or absorb it through their skin. People can also inhale tritium as a gas in the air.

What Are The Health Risks?

As radioactive water, tritium can cross the placenta, posing some risk of birth defects and early pregnancy failures. Ingestion of tritiated water also increases cancer risk.

Deficiencies in Regulations

The models used to evaluate the adverse health impacts of tritium have a number of weaknesses, including:

1.     Models assume tritiated water is uniformly distributed throughout the body. As a result, the EPA predicts that all organs, except for portions of the gastrointestinal tract, receive the same dose for a given intake of tritium. However, tissues with high water content receive a higher dose than tissues like bone or fat. Fetal tissues have higher water content than maternal ones. As a result, tritiated water is likely to be present in higher average concentrations in fetal tissues, as indicated by animal studies.

2.     If organically bound tritium becomes incorporated into DNA, it does not uniformly irradiate the whole cell; it preferentially irradiates the nucleus. Hence, the risk of damage to the DNA and of adverse health effects (including cancer but not only cancer) is considerably greater than if the tritium expended its energy in the cytoplasm of the cell.

3.     Models used to evaluate the dose received by the embryo in the first several weeks of pregnancy are seriously deficient. Current models assume that the dose to the embryo for the first eight weeks is the same as the dose received by the uterine wall. This is a reasonable assumption only for penetrating gamma rays. It does not apply to alpha-emitting radionuclides like uranium; nor does it apply very well to radionuclides like tritium that emit relatively low-energy beta particles. This is because alpha particles and low-energy beta particles do not travel very far, and thus the damage they cause is more localized than that from gamma rays.

4.     Low-energy beta particles, like those emitted by tritium, are often much more effective at causing harm than currently assumed by regulations. The effectiveness of different kinds of radiation in causing damage is taken into account by the “relative biological effectiveness” (RBE) factor. Current standards generally assume that gamma rays, x-rays, and all beta particles have an RBE of one — that is, the damage caused is directly proportional to the amount of energy deposited in the tissue. Alpha particles, on the other hand, which deposit all their energy in a smaller number of cells or even entirely in one cell, are assigned an RBE of 20. That is, the standards assume an alpha particle will do 20 times more biological damage than a gamma ray that deposits the same amount of energy in the body. As noted, the low energy of the tritium beta particle can result in the deposition of all the energy in a short distance, which could be particularly damaging if the tritium is in the DNA. This makes tritium’s beta particles not unlike alpha particles in some situations. Therefore, the RBE of tritium should not be taken to be equal to one for all forms of tritium, nor for all age groups.

5.     Regulations ignore age of exposure in determining the amount of damage done by tritium. For example the damage done to a fetus from organically bound tritium is more than four times that done to an adult from tritiated water and nearly ten times bigger than that assumed by current models.

6.     Organically bound tritium produces more serious health risks than tritiated water for the same amount of tritium intake for two main reasons.


  • First, the chemical form influences the likelihood of tritium being integrated into DNA or other biomolecules. Since tritium’s low energy beta particles don’t travel very far, there will be a big difference in the damage done by tritium located in the nucleus of the cell (where the DNA is located) to that located in the cytoplasm. Organically bound tritium ingested through food, for example, is more likely to be incorporated into biomolecules than tritium ingested by drinking tritiated water.


  • Second, OBT is more dangerous is that it is generally retained in the body longer than tritiated water. Human studies indicate that half of the tritiated water in the body is removed every 10 days, whereas removing half of the OBT present takes 21 to 76 days. For certain molecules with very slow turnover rates, this time can grow to 280 to 550 days. The longer retention times of OBT are a particular concern if the tritium is incorporated into tissues such as neurons (the main cells of the nervous system) or oocytes (immature egg cells). Considering that ova are formed once per lifetime, the effects of radiation on the reproductive system of female fetuses, and the possible effect on the children of females irradiated in the womb, could be significant.

Non-cancer effects

Beyond issues with cancer risk models, estimates of the health risks from tritium that focus only on cancer likely underestimate its actual impacts. The increased risks to pregnant women and the embryo/fetus include early miscarriages, malformations, and genetic defects. Risks can also be multi-generational given that a woman’s ova are produced while she is in her mother’s womb.


How Much Is Considered Safe?

Standards for tritium in drinking water range from 20,000 picocuries per liter in drinking water to 400 picocuries.


  • EPA: EPA’s standard for tritium in drinking water is 20,000 picocuries per liter.
  • Ontario Canada’s Drinking water quality standard for tritium is 540 picocuries per liter.
  • California’s recommended public health goal for tritium in drinking water is 400 picocuries per liter.
  • The Department of Energy agreed to an action level of 500 picocuries per liter for tritium in surface water in the clean up at Rocky Flats - a level corresponding to Colorado’s standard for tritium in surface water.


Therefore when reactor owners and the NRC dismiss public concerns about leaks, saying that tritium levels measured offsite by the plant operators were well below the EPA drinking water standard of 20,000 picocuries per liter and are “safe. This is not correct because:


All radiation protection regulations and the most recent report of the National Academies BEIR VII report concluded that the hypothesis that best fits the facts is that every exposure to radiation produces a corresponding cancer risk – low exposures produce low risk, and that risk increases with exposure. There is no threshold below which there is zero risk. The  EPA ’s method of expressing this reality is to set a Maximum Contaminant Level Goal (MCLG) which corresponds to zero health risk. The EPA value for MCLG for all radionuclides, including tritium, is zero.



400 picocuries per liter should be considered as an interim target limit for offsite surface water at all nuclear power plants while a better understanding of the impacts of tritium is developed. This level is 50 times lower than the EPA’s current drinking water limit and corresponds to a lifetime risk of a fatal cancer of about one in a million which is the goal of cleanup under the Superfund law, formally called the Comprehensive Environmental Response, Compensation, and Liability Act, or CERCLA.


What Are NRC’s Reporting Requirements?

Reporting Requirements for Liquid Releases: NRC’s reporting requirement for a minimum detection limit, also called the Lower Limit of Detection (LLD), is 2,000 picocuries per liter that can be increased to 3,000 picocuries per liter if no drinking water pathway exists. NRC believes that this is satisfactory because the EPA drinking water standard (20,000 picocuries per liter) is used as a reference. But it is quite unsatisfactory if the California public health goal (400 picocuries per liter) is the reference value. Evidently, for a reliable conclusion that the level is below 400 picocuries per liter, the LLD required should be consistently lower than that. We believe that NRC must tighten its tritium LLD to 200 picocuries per liter or less and require the specification of the LLD.

Tritium measurements are done quarterly, with composite samples that are collected at various intervals, commonly monthly. This means that samples from the times tritium is discharged (many times each quarter) and the times that it is not, are put together and averaged to give a quarterly result.

There are problems with this approach. There is generally no independent verification by the NRC of when the samples are actually taken. The NRC (and hence the public) depend on the reactor operators’ word that they are taken at the time of contaminated water discharge and not just before or well after. As a result, there is no verification of how representative the samples are and hence of the accuracy of the data in providing estimates of total tritium releases. If the samples are not coordinated with plant discharges occurring over a period of time and are not fully representative of the discharges, the estimates of total tritium discharges made using the results could be inaccurate. There is at present no independent way for communities and the public to verify what is occurring in terms of discharges measurements and reporting of the same.

Reporting Requirements for Gaseous discharges: As discussed in the foregoing, rainfall episodes that occur during gaseous discharge events result in the rainfall becoming contaminated with tritium. Despite the fact that such contamination could reach high levels under certain weather and tritium release conditions, data for rainfall near reactors are not part of the Environmental Reports filed by nuclear power plant operators. The NRC does not require rainwater monitoring nor monitoring of groundwater and surface water that may be affected by contaminated rainfall events.


How Releases Are Monitored?

NRC requires monitoring wells only if the groundwater onsite is used for drinking by the licensee; otherwise it is voluntary. In response to the proliferation of leaks from reactors around the country, especially at Braidwood NPS in Illinois where tritium leaks ended up in offsite drinking water, the NRC formed a Task Force in 2006. The task force’s findings and the NRC’s response are available on the NRC Web site at:  

NRC allowed industry to develop a voluntary NEI initiative instead of establishing regulation.


NEI's Buried Piping Integrity Initiative:

November 20, 2009 the Nuclear Energy Institute (NEI), the industry’s main lobby, indicated that the nuclear industry's chief nuclear officers voted to approve the proposed NEI "Buried Piping Integrity Initiative." NRC, in SECY-09-0174, said on page 4, that, “The staff plans to meet with the industry to further understand the initiative and monitor industry implementation. The staff will also evaluate the need to revise NRC Inspection Procedures to assess licensee implementation of this new initiative.” And further on page 13, “…the staff will determine whether to perform audits and/or develop a TI to assess licensee implementation of the industry Buried Piping Integrity Initiative.” (Emphasis added)

The initiative identifies actions to improve licensee's response to inadvertent releases underground. It relies exclusively on non-binding, non-required, non-regulated industry promises. The owners of NRC-licensed nuclear power plants have not committed to the NRC to do anything. Instead, they have a contractual obligation with the Nuclear Energy Institute. Thus, any owner opting not to submit information to the NRC will not be violating regulations or a regulatory commitment to the NRC, but only a breach of contract with NEI. And even if all owners dutifully honor their NEI contracts by submitting information to the NRC, there is public concern about the veracity and accountability for this voluntarily supplied information. There is a huge difference between the credibility of information submitted to NRC under 10 CFR 50.9 and/or 10 CFR 50.54(1) and information voluntarily submitted. The former is subject to regulatory sanctions if later determined to be incomplete or inaccurate.[6]

This contradicts the NRC staff's consensus that it recorded on use (and misuse) of voluntary industry initiatives following a September 1, 1998, public workshop on the subject in Chicago:


A comment from a majority of participants at the September 1, 1998, stakeholders meeting, including people with Interests in industry and the environment, was that Issues related to adequate protection of public health and safety are the responsibility of the NRC and should not be addressed through voluntary Industry initiatives. The staff agrees that relying on voluntary industry initiatives In lieu of NRC actions to ensure adequate protection would be inappropriate since they would be based on commitments rather than requirements. SECY-99-063, March 2, 1999


Entergy's BPTIP is available in Pilgrim Watch Presents Statements of Position, Direct Testimony and Exhibits Under 10 CFR 2.1207, March 3, 2008, Exhibit 14 found in NRC’s Electronic Library, Adams Accession No. ML0807404 along with a critique of Entergy’s BPTIP by Pilgrim Watch's expert, Arnold Gundersen, Exhibit 1, section 12, pages 3-13.















[1] Radioactive Rivers and Rain: Routine Releases of Tritiated Water From Nuclear Power Plants, Annie Makhijani and Arjun Makhijani, Ph.D. August 2009,,at 5



[3] Sejkora 2006 (Ken Sejkora, Atmospheric Sources of Tritium and Potential Implications to Surface and Groundwater Monitoring Efforts, Presented at the 16th annual RETS-REMP Workshop, Mashantucket, CT, 26-28 June 2006, link at, slide 22. Sejkora claims that testing fallout should result in a residual tritium concentration in rainwater of 100 to 300 pCi/liter  (slides 6 and 21). However, he did not take the dilution effect of the oceans into account. Actual data are presented in Tuttle 1992. They show that testing-related tritium had declined to less than low-end of natural background level of 5 pCi/liter by about 1990. See Tuttle 1992, Figure 1-3.]


[5] Health Risks of Tritium: The Case for Strengthened Standards, Arjun Makhijani, Brice Smith and Michael C. Thorne, IEER Publication, February 2007, at 10

[6] See Letter from David Lochbaum Re: Proposed Director's Decision Under 10 CFR 2.206, Table 2 provides an Abridged Listing Of Sanctions For Providing NRC With Incomplete And Inaccurate Information, available at: