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IN-99/06
On May 11, in accordance with the test
program established after Cycle XI refueling,
the 50% load rejection test was performed. 24
seconds after load rejection began, the reactor
tripped due to actuation of over-temperature
protection ∆T, as a result of anomalous
behavior of the condenser discharge bypass
valves in conjunction with a delay in reactor
control rod insertion. Once the causes were
analyzed, and after the valves were repaired
and the false contact of the reactor control
system speed board was rectified, testing was
performed on May 15.
Propietario-Operador:
Owner-Operator:
NSSS:
INFORMACIÓN GENERAL - GENERAL INFORMATION
Central Nuclear Vandellós II A.I.E.
72% Endesa, 28% Iberdrola
Westinghouse 3-Lazos PWR Loops
T - G: Mitsubishi TC6F - 49
Westinghouse TC6F - 44 (*)
Arquitectura/Ingeniería:
Architecture/Engineering:
Initec - Bechtel
IN-99/07
On July 1, while the compressed air system
service of the main switch was systematically
being changed to the redundant service, the
switch suddenly opened and caused a 100%
load rejection, and the resulting transient
resulted in very low level in Steam Generators
and reactor scram.
After analyzing the event, it was concluded
that a human error during maneuvers was the
cause of the incident.
IN-99/11
In conformance with monitoring requirement
4.3.2.1 of the Operating Specifications and GL-
96-01 “Testing of Safety Related Circuits”,
testing of the Engineered Safeguard Feature
slave relays began on August 13. On
performing the part corresponding to “main
steam isolation”, the purpose of which was to
test slave relay K627, isolation valve HV-AB26B
actuated unexpectedly. Partial closure of this
valve caused a steam flow reduction, the
resulting run-back order due to overpower ∆T,
and a major transient without reaching scram.
The appropriate modification of the
Operating Specifications has been requested to
prevent undesired transients in operation at
power.
The other reportable events, though
important, were not as relevant as the ones
mentioned above. All of them led to the
necessary technical and administrative actions to
prevent recurrence. In any event, nuclear safety was
not affected in any of the cases.
REFUELING
The 10th refueling outage of Vandellós II NPP
began on March 14. Prior to that date, the cycle was
extended for 24 days and the plant was disconnected
from the grid after 520 days of continued operation
(a record for our plant).
In addition to normal refueling activities, this
particular refueling marked the end of the first inservice
inspection period, which involved an
additional workload of inspections and tests to
complete the required scope. In addition, major
improvements and technological upgrades had been
scheduled, and power was uprated from 2,775 to
2,900 MWt.
The following activities are noteworthy due to
their magnitude, impact or atypical nature:
• Replacement of the three low-pressure turbines
and the high-pressure turbine; execution was
excellent and completed in a record time of 39 days.
• Modifications in Main Alternator (stator coil
rigidification, magnetic packet retightening, and
Operación Comercial: 8 de Marzo de 1988
Commercial Operation: March 8, 1988
Datos Técnicos Principales:
Main Technical Data:
- Potencia Térmica del Reactor: 2.900 MWt. 2.785 MWt. (*)
- Reactor Thermal Power:
- Electricidad Bruta Nominal: 1.082 MWe. 1.009 MWe., origen 982 MWe. (*)
- Rated Gross Electricity: 1,082 MWe. 1,009 MWe, at source 982 MWe. (*)
- Nº de Elementos Combustibles: 157 (17x17)
- Nº of Fuel Assemblies:
- Edificio de contención:
- Containment Building:
- Tipo: Hormigón Pretensado Atmosférico.
- Type: Atmospheric Prestressed Concrete
- Presión de Diseño: 3,78 kg/cm 2
- Design Pressure: 3.78 kg/cm 2
- Diámetro Interior: 40 m.
- Inside Diameter: 40 m.
- Altura Interior: 62,8 m.
- Inside Height: 62.8 m.
(*) Antes del aumento de potencia
RECARGA
El día 14 de marzo se inició la
10ª parada de Recarga de CN
Vandellós II, previamente se había
realizado un alargamiento de ciclo
de 24 días y la desconexión de la
red se produjo después de 520 días
de operación continuada (récord en
nuestra planta).
Además de las actividades propias
de cada Recarga, en ésta cabe
destacar que era la que marcaba el
final del primer intervalo de inspección
en servicio lo que implicó una
carga adicional de inspecciones y
pruebas para completar los alcances
requeridos, además se habían programado
importantes modificaciones
y mejoras tecnológicas, y se llevó
a cabo el aumento de potencia
desde 2.775 hasta 2.900 MWt.
Por su magnitud, impacto o por
ser atípicas podría destacar las siguientes:
• Cambio de las tres turbinas de
baja presión y la de alta presión,
trabajo realizado de manera excelente
y en un tiempo récord de 39
días (virador a virador).
• Modificaciones en Alternador
Principal (Rigidización bobinas estator,
reapriete paquete magnético y
sustitución bornas por otras refrigeradas
por agua) 29 días.
• Modificación de los Transformadores
Principales para adaptarlos
a la nueva potencia.
• Modificación del sistema de refrigeración
del estator.
• Sustitución del sistema de
Control Electrohidraúlico de Turbina
(DEH).
• Modificación entradas de vapor
al condensador para evitar erosiones
en el haz tubular.
• Cambio del colector de agua
alimentación principal como consecuencia
de seguimiento por erosión-corrosión.
A b r i l 2 0 0 0
R e v i s t a S N E