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