TMI-1

Three Mile Island

July 20 – The NRC granted requests from TMI operator Exelon for relief and allowed it to use alternative procedures to certain requirements for in-service examination of components and steam pressure tests conducted during 10-year intervals. The requests were part of the fourth 10-year inspection that began on April 20, 2011 and ends no later than April 19, 2022.

2001-2011

• From October 5-9, 2001, “Licensee sirens in Lancaster County were inoperable October 5 through October 9, 2001, due to a radio transmitter being deenergized at the county facility. The transmitter is part of the siren actuation system. This issue is unresolved pending further investigation into the lines of ownership and maintenance of the actuation system.” (IR 50-289/01-07).
• On January 11, 2002 , Siren testing at TMI encountered numerous problems: all sirens failed in York County and one siren failed in Lancaster County. AmerGen attributed to computer malfunctions.
• On March 3, 2002, a siren malfunctioned in York County again. During TMI’s annual test on on January 30, 2002, all 34 sirens in York County, located within ten-miles of the plant, failed to activate.
• On June 25, 2002, “...station emergency preparedness personnel discovered that the emergency planning siren base station at the site, was unable to communicate with the off site sirens, due to external radio frequency noise in the area.” (IR-50-277/02-05; 50-278/02- 05)
• On December 12, 2002, TMI sirens malfunctioned in Cumberland and York counties. In Dauphin County, 28 sirens malfunctioned due to the “inadvertent” discharge of the “space bar” by a computer operator (Refer to June 22, August 15 and October 5-9, 2001 and January 11, March 3 2002, for related problems.)
• On July 28, 2010, the NRC issued a report of an inspection at the Three Mile Island plant for the quarterly period ending June 30.
  The NRC said it found no findings of significance. However, it noted that the TMI plant operator identified a violation that was determined to be of very low safety significance. The NRC said it would treat the violation as a non-cited violation.
  The issued stemmed from the TMI Emergency Plan and the plant paging system. The report said that plant operator Exelon began testing its on-site speakers in March 2010. A total of 301 out of 405 speakers were tested, and of those tested, 108 had identified deficiencies, the report said. “Contrary to the TMI Emergency Plan, the 108 speakers would not provide immediate warning and instruction to on-site personnel during an emergency,” the report said. “Upon discovery, Exelon issued a standing order to issue blow horns to operations and security staff to notify people in areas that would need to be evacuated during an emergency.“ The report added, “The finding is of very low safety significance because prompt compensatory measures were taken upon discovery.”
• June 23, 2011, Three Mile Island's emergency sirens sounded at 12:15 p.m. Thursday as part of an annual test -- but it didn't work everywhere. The 96 sirens, which cover five counties and are within a 10- mile radius of TMI, were set to sound for three minutes. They sounded everywhere except in Lancaster County.
  Officials ran another test, this time just in Lancaster County, at 1:15 p.m. At that time, the sirens did work in Lancaster County. (WGAL)
  A Lancaster County EMA official said Lancaster County and another county pressed the siren test button simultaneously and the system did not register the Lancaster County test.
• July 14, 2011, A Three Mile Island warning siren sounded accidentally on Thursday afternoon, according to Dauphin County officials.
  The TMI siren at 2nd and Hanover streets in Hummelstown inadvertently sounded at 1:19 p.m. It lasted for fewer than 30 seconds, according to Stephen Libhart, Director of the Dauphin County EMA.
  Libhart says Exelon will repair or replace any components of the siren if necessary. (WGAL)

 To read the NRC memo related to the TMI operators license exam, open pdf: 

The following is the full content of a report that an "event" at

the Three Mile Island nuclear power plant's Unit 1 reactor had been retracted.

In this case, the "event" refers to three safety relief valves not opening as

they were set to do. "Retraction" does not mean the situation described did not

occur, it means that it will no longer be categorized as an "event."

!!!!! THIS EVENT HAS BEEN RETRACTED. THIS EVENT HAS BEEN RETRACTED !!!!!

Power Reactor Event Number: 45464

Facility: THREE MILE ISLAND

Two former spokesmen for the nuclear plant say they're surprised Exelon waited more than 5 hours to announce a radiation leak.

By Jan Murphy 

The Three Mile Island nuclear station's former operators learned from the 1979 partial reactor meltdown that there's no such thing as overcommunication about TMI.

Two former spokesmen for GPU Nuclear Corp., which operated the facility after the 1979 accident, said that based on lessons learned from that incident, they subsequently alerted local officials about every minor event at the plant, such as when an ambulance was called or a steam release was loud.

They issued so many notifications that officials receiving them complained.

"The operation of a nuclear power plant is based on trust, and communication is an exercise in trust," said Douglas Bedell of Cornwall, who was a communication manager for GPU Nuclear.

Fallout focuses on Exelon’s decision to wait 5 hours before calling local and state officials.

EFMR downloaded data from its real-time gamma monitors around 

Three Mile Island on Sunday, Nov. 22, 2009.

There were no unusual off-site readings for Saturday, Nov. 21 through 4 p.m.  

EFMR Monitoring, Inc. (efmr.org) is  a nonpartisan community based 

organization established in 1992. EFMR monitors radiation levels at 

Peach Bottom and Three Mile Island nuclear generating stations, 

invests in community development, and  sponsors remote robotics

research.  

Posted on Mon., Nov. 23, 2009

By Jan Hefler

Philadelphia Inquirer Staff Writer

Investigators with the U.S. Nuclear Regulatory Commission yesterday found that a minimal amount of radiation had leaked inside a reactor at the Three Mile Island nuclear power plant Saturday afternoon but did not pose any health threats to the public.

However, some state and local officials, including Gov. Rendell, said they were upset that notifications were not made in a timely way to authorities.

Diane Screnci, NRC spokesperson, said that the leak had "no effect on public health or safety" because it was confined to a reactor building at the central Pennsylvania plant, about 10 miles south of Harrisburg. She also said about 20 of the 151 workers inside the building either inhaled radiation or touched contaminated surfaces, but said the amount was not harmful.

New sirens to include battery back-up power  

LONDONDERRY TOWNSHIP, PA  (Nov.19, 2009)

Exelon Nuclear will begin a project next week to 

replace all 96 emergency sirens in the 10 miles around Three Mile Island Generating Station with sirens that 

include battery back up.  The first phase of the project will have contractors visit and identify certain features 

of each existing siren.