TMI Update: Jan 14, 2024

The EFMR Monitoring Group is installing continuous radiation monitors at several locations around the Three Mile Island nuclear power station.  The monitors are connected by telephone to a central computer, which downloads the data and displays it.  The monitors can be set to record data at preset intervals varying from minutes to hours and can store 1500 data points.  The data is downloaded via a dedicated telephone line at preset polling intervals.  If the radiation level exceeds a preset alarm level the data is automatically downloaded to the central computer and a polling of all stations is initiated.  The software allows the data to be displayed as tables, graphs or readings on a diagram or map.

The monitoring station consists of a Thermo Eberline ESM Model FHZ 621 G-L4 wide range detector in a weatherproof housing.  The housing also contains an uninterruptible power supply (UPS) and DC power supply, which operates the detector, the RS232 interface adapter, and a telephone modem.  The battery in the UPS will operate the monitor and modem for several hours after loss of AC power.  The detector is capable of measuring dose equivalent rates from background to 10 rem/hour.  The detector also has a feature that uses the difference in radiation energy between natural background radiation and reactor fission product radiation to determine whether small radiation increases are from natural or man-made sources.  The chart below shows data from one of the monitors during a 48-hour test.  The peak is from a ¹³⁷Cs calibration source.

Five monitoring stations have been purchased and the electrical and telephone installations have been completed for 3 stations as of 27 Mar 03.  The other two stations are being used for testing and will be installed when the computer programming and testing is complete.

Export Witness Report: Three Mile Island Litigtation by Arnold Gundersen (Download PDF)

Post Accident Containment Leakage by Arnold Gundersen (Download PDF)

Preliminary Estimates of Radioactivity Releases from Three Mile Island by Lake Barret, NRC (Download PDF)

From GlobalPost:

To get independent answers about the risks faced by people, GlobalPost turned to Arnold Gundersen, a 39-year veteran of the nuclear industry. Now chief engineer at Fairwinds Associates, he has worked as a nuclear plant operator and he served as an expert witness in the investigation into the Three Mile Island accident.

GlobalPost: Officials have said the possibility of a large-scale radiation release is small. Do you agree?

Arnold Gundersen: I think that the probability of a large scale release is about 50-50, and I don’t call that small.

GlobalPost: Why do you think that?

Gundersen: For several reasons. One, you’ve got three reactors involved. Two, you’re already picking up radiation on aircraft carriers a hundred miles away at sea, on helicopters 60 miles to the north, and in town. So clearly, as these plants become more and more difficult to control, it becomes quite likely that a containment now will have a gross failure. And a gross failure will release enormous amounts of radiation quickly.

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From the Philadelphia Inquirer:

Japanese officials continue to struggle to contain the damage at a nuclear plant in Fukushima, but it may be much harder to limit the fallout for the future of nuclear energy in the United States.

Images of an explosion Saturday and word of a possible partial meltdown have rippled around the globe and are expected to linger for U.S. nuclear advocates already wrestling with their own economic and political challenges.

"This is obviously a significant setback for the so-called nuclear renaissance; the image of a nuclear plant blowing up on the television screen is a first," said Peter Bradford, a former commissioner for the U.S. Nuclear Regulatory Commission and a frequent industry critic. "Those cannot be good things for an industry that's looking for votes in the Congress and in the state legislatures."

Already, some on Capitol Hill are bringing back memories of the nuclear disasters at Three Mile Island and Chernobyl.

Rep. Ed Markey (D-Mass.) called Saturday for the NRC to impose a moratorium on building new nuclear reactors in seismically active areas until a sweeping new safety review is completed, and he demanded reviews of the Japanese plant's design to determine if there were flaws that could repeat themselves elsewhere.

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The NRC requested an Annual Assessment Meeting with Exelon to review the results of the NRC's assessment of the safety performance of the Peach Bottom Atomic Power Station for calendar year 2010. The NRC's assessment is documented in a letter dated March 4. 2011.

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SUMMARY OF FEBRUARY 22, 2011, MEETING WITH EXELON TO DISCUSS THE PROPOSED ELIMINATION OF CONTAINMENT ACCIDENT PRESSURE CREDIT FOR PEACH BOTTOM ATOMIC POWER STATION, UNITS 2 AND 3

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PEACH BOTTOM ATOMIC POWER STATION, UNITS 2 AND 3 - REQUEST FOR ADDITIONAL INFORMATION REGARDING LICENSE AMENDMENT REQUEST RELATED TO LIQUID NITROGEN STORAGE (TAC NOS. ME4131 AND ME4132)

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From the Patriot News:

Former Pennsylvania Gov. Dick Thornburgh said he experienced “a large dose of deja vu” as he watched news of the nuclear reactor crisis in Japan.

In March 1979, Thornburgh had been in office for only 72 days when a relief valve failed to close on the Unit 2 reactor at Three Mile Island, producing what Thornburgh called "the chilling prospect of a meltdown at the facility."

The circumstances are different in Japan, said Thornburgh, but the problems are very similar.

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The crippled Fukushima reactor is a grim reminder of the Three Mile Island crisis. It has some common technical and safety aspects, and brings to mind broken promises by the industry to resolve open safety issues. The Japanese crisis certainly demonstrates the propensity for obfuscation by the industry while the public is left sifting through hundreds of media reports.