US tornado risk map: This map features the US regions which are prone to strong winds, hurricanes and destructive twisters. Found on: blacksamcashinterestingthigs.blogspot.com
Right, these guys have tornado warnings all the time. Basically I bet you the history is they come and go harmlessly within a half an hour or so. Bet you the shift supervisor thought, I will lollygag around trying to shutdown…it will all clear away in minutes and I will save my company tons of money instead of scramming both plants.
This hasn't been covered in a inspection yet...these guys are so dangerous...the whole entergy fleet. They are dangerous for our nation!
Wiki: Overall, the tornado remained on the ground for an hour, from 7:06 p.m. to 8:06 p.m. (0006 – 0106 UTC), and traveled along a 41.3 miles (66.5 km) path. Sixteen people lost their lives due to the tornado,[16] making it the deadliest in Arkansas since an F4 killed 35 on May 15, 1968.
Tornado path
Tornado Path
This gives you an idea of how much planning time they got before a tornado hits.Russellville is about where ANO was.So the massive EF 4 tornado passed about 50 mile east of the plant. Why didn’t they just scram? If the tornadoes was directly heading right for them, would they bungle it by doing the normal shutdown. Right, the time frame in the LER is from 1912 to 2002. The EF 4 tornado was passing 50 miles to the east of them...between them and Little Rock. I bet you the whole front that passed directly over them had dire warnings of intense tornadoes. The tornado began at 7:25 pm and completed at 9:24 pm. You get it, the Tornado began at 7:25 pm on April 27, 2014, with the system operator saying we are in a grid emergency telling the ANO to come off the line as soon as possible at 7:34pm…
Man, have these plants been off the line so much for stupidity in the last few years...
Description. On April 23, 2010, Units 1 and 2 were notified of a severe thunderstorm warning at 1:50 p.m. Procedure OP-1203.025, "Natural Emergencies," Revision 30 was entered. At 3:25 p.m. the licensee received a tornado warning, transitioned into a tornado watch at 4:12 p.m. and exited the watch at 8:00 p.m. The resident inspectors observed entry into the procedures and subsequently performed a site walkdown to ensure all potential missile hazards were identified and controlled as directed in the natural emergencies procedure.>>>You got to the know the stimulator should have picked up the bum reactivity procedure...bet you the simulator modeled this inaccurately...
...to go over the high ponts of how they are going to shutdown or downpower the reactor and the issues near refueling.
... By the way, I doubt they could see real power level. They had no idea where power was…the power reading shown by the detectors and meters up in the control room were wildly are inaccurate. Don’t worry, this is normal…
Arkansas Nuclear One: Reactor Power Running Completely Out of Control
The NRC’s ROP’s is tolerating nuclear plants
running widely out of control and this government regime or oversight don’t
cause bad operator to change their bad ways.
This is the same event as 2010...they don't learn from earlier near misses. So Entergy has all this NRC activity concerning the stator yellow finding, killing of the one and injuring 8 others, the so called internal changes out of this...and these events happen over and over again as if the NRC has just the power of a gnat.
These guys are extremely dangerous and are a threat to the whole US nuclear industry, for that matter, nuclear power worldwide.
A review of the ANO corrective action program and Licensee Event Reports for the previous three years was performed. There was a similar condition relative to the effects of ASI found in 2010 at ANO-2. The ASI TS limit was exceeded during a planned down power. The cause was identified to be an inaccurate reactivity management plan which contributed to the crew not being aggressive enough with ASI control.
Unit 1: March 31, 2013,
Axial Shape Index Trip at the End-of-Life
During Rapid Plant Shutdown
ANO: 04 26 2014
During severe weather on April 27, 2014,
both units at Arkansas Nuclear One (ANO) were informed of a system-wide grid
emergency and were ordered to come off-line as soon as possible. Both units
commenced a rapid plant shutdown. ANO, Unit 2 (ANO-2) was at the end of the
core life. During the shutdown, the Axial Shape Index (ASI) became more
negative (power rising to the upper portion of the core) during the shutdown.
This led to one channel of the Plant
Protection System (PPS) to be actuated on an ASI auxiliary trip. At this time,
the direction to manually trip the reactor was given, but before the action could
be taken, an automatic reactor trip occurred due to the two-out-of-four PPS
logic being made up for the ASI conditions. The cause of this condition was not
effectively executing the reactivity management plan by delaying insertion of
Control Element Assemblies (CEAs) and not inserting CEAs deep enough to maintain
ASI within the desired control band.
2 July 2014A March 2013 crane accident at Entergy's Arkansas One nuclear power plant that killed one worker, injured eight others, damaged the plant and required days of backup emergency diesel power was judged to be of substantial safety significance by the US nuclear regulator.
Workers were moving the 525-ton main generator stator out of the plant's turbine building during maintenance when a temporary lifting assembly collapsed, causing the component to fall, damaging plant equipment, killing one person and injuring eight others.
Unit 1 was in a refuelling outage at the time, with all of the fuel still in the reactor vessel, safely cooled.
The stator fell on and extensively damaged portions of the Unit 1 turbine deck and subsequently fell over 30 feet into the train bay. The stator drop resulted in a Unit 1 loss of offsite power for 6 days and a Unit 2 reactor trip and loss of offsite power to one vital bus. The dropped stator ruptured a common fire main header in the train bay, which caused flooding in Unit 1 and water damage to the electrical switchgear for Unit 2. The alternate alternating current diesel generator (station blackout) electrical supply cables to both units were pulled out of the electrical switchgear and the diesel was therefore not available to either unit, according to a 24 March 2014 follow-up inspection report (NRC document ML14083A409).
Unit 2, which was operating at full power, automatically shut down when a reactor coolant pump tripped due to vibrationscaused by the heavy component hitting the turbine building floor when it fell. Unit 2 never completely lost off-site power, and means existed to provide emergency power using the diesel generators, said the regulator in a press release.
In September 2013, the US government's Occupational Safety and Health Administration cited Entergy and three contractors, Precision Surveillance Corp, Bigge Crane and Rigging and Siemens Power Generation for 26 safety violations.
The nuclear regulator blamed Entergy for approving a temporary gantry design not supported with adequate documentation, for failing to identify load deficiencies in the vendor's calculations, failing to identify a component of the wrong size in the north tower. It also said that the tower was not designed for 125% of the load, and inadequate load testing (including a 125% proof load test) was carried out before the lift.
Initially, the regulator assessed the risk significance of the event at the highest level, red, for unit 1, and at the next lower level, yellow, for unit 2, but reduced the unit 1 significance to yellow after Entergy gave evidence in a 9 May conference arguing that there was a high likelihood of success (90%) for recovering electrical power to cooling pumps before water in the core boiled away, exposing fuel.
An Entergy spokeswoman said: "Entergy is dedicated to the safe operation of Arkansas Nuclear One, and we take the NRC's findings very seriously. We are committed to learning from this tragic incident, sharing our knowledge with the industry, and ensuring that it never happens again."
As of early July, the nuclear regulator was still determining what its response to the incident would be.
Training material is being modified to
include details on the dynamic effects of ASI change that occurs at the end-of-cycle.
Additionally, improvements to the guidance in the reactivity plans that involve
rapid plant shutdowns are being made as are changes to the standards for use of
CEAs during transients.
During the shutdown, the operator performed
manual turbine load reductions, CEA insertions, and was responsible for the
boration. Multiple alarms were received throughout this event due to the continuous
storm activity (lightning strikes on the grid). In addition, there were
multiple phone calls from the SOC dispatcher concerning the state of the grid,
the down-power, and related issues. These distractions were determined to be a
contributing cause for the automatic reactor trip.
The reactivity management plan was not
effectively executed due to lack of specific training on understanding the magnitude and rate of ASI
shift that occurs at the end of a fuel cycle and the optimal approach to control ASI during the
performance of a rapid plant shutdown at the end of core life.
Not have adequate procedures or training issues is an excuse...
The approved
reactivity plan that was being used during this event included target CEA
positions that reflected CEA insertions of 17 to 19 inches being necessary to keep
ASI on target between each of the provided 15-minute intervals. Reactivity
plans are written to 15-minute intervals for timing the expected CEA insertions
and boration rates needed to maintain ASI on target through the prescribed maneuver.
The rate of CEA insertion needed was only evident in the numerical CEA position
targets provided in the plan. There was no additional guidance on rate of insertion
or size of insertion steps provided in the text of the plan. The operator
delayed CEA insertion over the initial interval because it was noted that ASI
was tracking closely with the target ESI early into the maneuver. This delay in
CEA insertions was found to be a direct contributor to the challenges
associated with maintaining ASI in the desired control band which ultimately
led to the automatic reactor trip.
In other words, when the moderator temperature coefficient heads towards the postive direction the safety feedback of the cofficient become much less...when the coefficient becomes positive, as the coolant temperature increases, this adds reactivity uncontrollably. This is the Chernobyl. This is the ABC's of nuclear professionalism.
Due to the negative moderator temperature
coefficient that exists at low boron concentrations, control of ASI in the
ANO-2 core, is challenging during end-of-cycle maneuvers. The magnitude of the temperature-driven
ASI shift requires aggressive insertion of CEAs during end-of-cycle power reductions.
The delay in the insertion of the CEAs and the smaller rate of insertion than
needed resulted in the TS limit being exceeded.
A review of
the ANO corrective action program and Licensee Event Reports for the previous
three years was performed. There was a similar condition relative to the effects
of ASI found in 2010 at ANO-2. The ASI TS limit was exceeded during a planned
down power. The cause was identified to be an inaccurate reactivity management
plan which contributed to the crew not being aggressive enough with ASI
control.
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