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Off-Site Air Radiation Monitoring Systems

Monitors that measure airborne emission of radionuclides from the Pilgrim NPS include: the Sage System consisting of 14 real-time monitors installed on the edge of Pilgrim NPS’s property; thermoluminescent docimeters (TLD’s) placed in 42 locations within 5 miles of Pilgrim NPS; real-time monitors placed in a few schools for the sole purpose of educating students and not necessarily adequately monitoring emissions. These systems are part of Massachusetts Department of Public Health Radiological Control Program.

1.  Sage System - Real Time Off-Site Monitoring System

This system consists of gamma radiation detectors located at 14 different locations at a one mile ring (really not a ring, an arc) around the Pilgrim Nuclear Power Station. These on line detectors transmit radiation levels on a continuous basis by telephone line to a centralized data logger and computer at the office of the Radiation Control Program. This began in April 1991.


The Sage System does not provide any significant protection to the citizens of Southeastern Massachusetts.  The “NRC Draft Report For Comment On Findings On Issues Of Offsite Emergency preparedness For the Pilgrim Nuclear Power Station [NUREG-1438], issued May 1991, expressly noted that MDPH installed this system, “even though fixed offsite monitors are no longer endorsed by the NRC...”[ page 2-159].


Under the agreement with the licensee, the monitors were installed less than a quarter of a mile from the plant.  Yet, the NRC has found that monitors closer than 1000 meters [about 2/3 of a mile] would provably provide inaccurate readings in the event of an accident.


The agreement included 22 potential monitoring sites, but only 14 have been installed.  Again this is contrary to NRC research on real time monitoring, which concluded that using as few as 14 monitors would grossly underestimate the radiation from narrow emission plumes.


The monitors are only in a small quadrant behind the plant.  Therefore, there is no effective monitoring in the directions of Scituate, Marshfield, Duxbury, Kingston, or much of Plymouth [ including the Gurnet, Saquish neck at the end of Duxbury barrier Beach}.  Granted, the plant is on the coast but there is no reason why monitors are not placed on Gurnet, and on strategically placed locations on Duxbury, Kingston, Plymouth shores and interior locations. Click for Wind Direction Map.


There are no monitors on Cape Cod.  The Cape is across open water -- nothing to break up a plume.  The Cape is downwind 3/4 of the year.  See accompanying wind chart.  The Cape has statistically significant breast and prostate cancers which epidemiology studies to date have not been able to completely explain. Click for Wind Direction Map


The placement of the Sage monitors is particularly troublesome in view of the extensive wind analysis done by the Harvard School of Public Health, under the direction of Dr. J.D. Spengler and Dr. G.J. Keeler, May 12, 1988.  This study was commissioned by MDPH and is entitled, Feasibility of Exposure Assessment For the Pilgrim Nuclear Power Plant.  The placement of the Sage monitors effectively ignores the results of this study that MDPH both commissioned and paid Harvard to conduct.  By way of contrast, I would point out that, at Seabrook station, the Citizens Monitoring Network is installing monitors on buoys at sea.


The Sage monitors do not measure high and low let alpha and beta radiation – only gamma.


The Sage System also seems subject to the critical deficiencies outlined by Alfred Schmidt, engineer/consultant Schmidt Instrument CO., San Carlos, California in his comments to EPA, March 31, 1992.  For example, he states, “ Many of the off-site air sampling systems are ...deficient because they are housed in virtually closed metal shelters which seriously restrict the flow of particle laden air to the collection filters.


The Sage System lacks software to make any sense out of the computer data arriving at MDPH.  The data is neither systematically graphed nor charted.  There is just a meaningless pile of numbers in some MDPH office -- doing nobody any good.


2.  Thermoluminescent Dosimeters (TLD’s)

TLD’s are placed in 42 locations within 5 miles of Pilgrim NPS to measure gamma radiation levels.  These devices are passive in as much as they must be in place for a period of time [3 months] and then brought back to the laboratory to determine the amount of radiation the device received at that location for that period of time.

Deficiencies TLD’s

TLD’s provide only an average figure, and increases of potential significance can be masked by lower than average readings during other parts of the month.  Biological impact occurs on a daily basis 


TLD’s can only read to a maximum threshold, that is, like a film badge they can only read so high.


TLD’s do not read high or low let alpha and beta.

bullet Dr. Hoffman, at Penn State, did an analysis of TLD’s and concluded they provided poor sensitivity to Zenon 133.  He said it took about 85 hours at maximum concentration before anything showed up  and that even then the amount was underestimated by a factor of around 20.
bullet The TLD’s are placed only within 5 miles of Pilgrim NPS.  There is no magic shield at that boundary.


3. High School Monitoring Project

This system consists of radiological and meteorological monitoring systems at each of 7 high schools [3 in Plymouth; 1 each in Carver, Kingston, Duxbury and Marshfield].  These on-line monitoring stations are connected by modem to each other and to MDPH.

Deficiencies:This program was initiated by the Governor’s Council on Radiation Protection solely as a teaching device for the students, not as a monitoring device to protect public health and safety. They recognized that this important job must be performed by trained personnel and could not be left to janitors, students or teachers.


It is overly optimistic to assume that the schools are all coincidentally placed in the most favorable locations in regard to population density and meteorological conditions.


The High School monitors, like the Sage, have poor sensitivity to low energy gamma and beta.  To be protective of public health they should measure gamma, beta and alpha radiation, at both the high and low energy levels.  For example Iodine-125 is at the 60 KeV and most iodine’s are under 100 KeV.


Calibration and testing of equipment is not adequately and consistently performed.


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