Mexico

INES-event
INES 1

Non Usual Event declared due to loss of outside power at Laguna Verde NPP U1

On December 02, 2010, Laguna Verde NPP Unit 1 was operating at 87.5 % rated power, when a loss of outside power event ocurred, and a Non Usual Event was declared by the operator. All safety systems worked as required, including all three diesel generators; and the reactor was taken to a safe shutdown condition.

Category: Power Reactor Mexico »

INES-event
INES 2

Engineering Safety Feature Inoperative at Laguna Verde NPP-1

On July 12, 2002 while the reactor was increasing power following inspection and repairing of small leaks in the main steam tunnel, there was an automatic shutdown. The cause was human failure of the main control personnel to control reactor pressure. During recovery actions, it was found that the Reactor Core Isolation Cooling system (RCIC) was inoperative.

Category: Power Reactor Mexico »

INES-event
INES 2

Internal contamination of workers in a Medical Center

On November 28, 2002 a technician of the Nuclear Medicine Department of the Medical Center “Centro Médico Siglo XXI” reported to the National Commission on Nuclear Safety and Safeguards - CNSNS (Mexico’s nuclear regulatory body) that he and eight of his co-workers were contaminated with I-131. The technician became aware of the problem because radiation alarms activated while his co-workers were around. The nine workers were checked with a whole body counter at the regulatory body’s laboratory, and the results verified the internal contamination of the workers.

Category: Other Mexico »

INES-event
INES 2

Fuel assembly drop during refuelling

On November 21, 1998 while performing refuelling, at the time of unloading the core and lifting a spent fuel assembly, a failure occurred affecting the refuelling machine which caused the spent fuel assembly to slump to the reactor core. The fuel assembly was taken to a safe condition. Reactor vessel water and refuelling floor atmosphere were monitored without finding any abnormal changes.

Category: Power Reactor Mexico »

INES-event
INES 1

AN IMPORTANT LOSS OF COMMUNICATIONS IN MAIN CONTROL ROOM

On January 18 at 10:30 hrs. the communications system failed to work from the main control room to other areas of the plant at the time of establishing contact. This emergency was declared as a 'non usual event'. At 10:45 hrs the emergency notifier was given notice by the loud speakers and CNSNS was also informed by phone, extension 300, of pere at Cat (Technical Support Center). At 12:45 hrs. phone extension 243 was back in operative condition, therefore ending the event.

Category: Power Reactor Mexico »

INES-event
INES 1

RECIRCULATION TRANSIENT WITH A SUDDEN INCREASE IN POWER OVER 100%

Valve RRC-FCV-8830B opens, the HPU-B subloop 2 trips and subloop 1 does not start in its auto mode producing a peak in the neutronic flux: APRM A 108%, APRM C 109%, APRM D 115% and the flow through the core is 29.4 KT/hr. Power can be lowered with the recirculation loop A: loop "A" 1550 LPS; Loop "B" 1890 LPS and power is at 1915 MWT.
Initiator event: recirculation transient with a sudden increase in power frequency: expected.

Category: Power Reactor Mexico »

INES-event
INES 1

A NON USUAL EVENT DUE TO THE LIBERATION OF GASES INSIDE THE PLANT

A non usual event was declared due to the detection of domestic gas odor. The cause of the event was the activation of the relief valve of the stationary tank of gas placed at the roof of the control building. The gas was suctioned by the HVAC system. This event took place during the task to fill the tank.

Category: Power Reactor Mexico »

INES-event
INES 1

LOSS OF INTERNAL POWER DUE TO THE TRIP OF THE MAIN TRANSFORMER (T-1)

Loss of internal power due to the trip of transfromer T1 because of the activation of relay 286/GT, when the down side touch ground producing scram and isolation, with the plant being in condition 5, the GD-II started and delivered the loads in a sequential form, with the back up transformer (T-5). Bus - 1A1 was fed. Recovering scram and isolation. The event lasted 13 seconds.
Initiator event: None; frequency: possible; availability: adequate. Original classification "1" (from Table 1 column 2C from the INES users manual).

Category: Power Reactor Mexico »

INES-event
INES 1

REACTOR SHUTDOWN BY TECHNICAL SPECIFICATIONS APPLICATION (UNUSUAL EVENT)

This event was intitated at 6:10 p.m. on May 9, 1992 when technicians, while performing the functional testing of pressure instruments of reactor recirculation pumps trip for ATWS, put one out of four switch selectors on "testing position" to verify the functional instrumentation operation and due to a mistake in the procedure application and communication deficiency between technicians, the trip logic was completed and a recirculation pump trip occurred. The operators reduced power to about 35% power according to technical specifications and following the abnormal procedures.

Category: Power Reactor Mexico »