15 février 2018
Le réacteur connaît ce problème pour la troisième fois depuis le 5 décembre 2017 !... Cette perte de données entraine l’impossibilité d’action d’urgence en cas de survenue de rupture de tube de générateur de vapeur... et pour la troisième fois ce sont des mesures locales au compteur Geiger qui assurent le contrôle de la radioactivité de la ligne de vapeur principale.
Alors que les générateurs de vapeur ont 25 ans de fonctionnement et que la fragilité de ce composant lourd est bien documenté, la NRC rassure en écrivant qu’il y a intégrité des gaines de combustible et des tubes des générateurs de vapeur (Comanche Peak Nuclear Power Plant [CPNPP] has assurance of steam generator integrity and fuel cladding integrity and there is a negligible safety significance to the current condition from a public health and safety perspective.)
Type : PWR - Puissance : n° 1 : 3 612 MWth - n°2 : 3 458 MWth - Première divergence n°1 : 4 / 1990 - n° 2 : 3 / 1993 -
Available in english only
Event Number : 53212
Facility : COMANCHE PEAK - State : TX
Unit : [2] - RX Type : [2] W-4-LP
Event Date : 02/15/2018 - Event Time : 03:06 [CST]
Emergency Class : NON EMERGENCY 10 CFR Section : 50.72(b)(3)(xiii) - LOSS COMM/ASMT/RESPONSE
Initial PWR : 100 % Current PWR : 100 %
Event Text
MAIN STEAM LINE RADIATION MONITOR DETERMINED TO BE NON FUNCTIONAL
"At time 0306 [CST], Main Steamline Radiation Monitor 2-RE-2326 (Main Steamline 2-02) reading spiked and declared non-functional.
"With this radiation monitor non-functional, all of the emergency action levels for a steam generator tube rupture in steam generator 2-02 could neither be evaluated nor monitored. This unplanned condition is reportable as a loss of assessment capability per 10CFR50.72(b)(3)(xiii).
"Comanche Peak Nuclear Power Plant [CPNPP] has assurance of steam generator integrity and fuel cladding integrity and there is a negligible safety significance to the current condition from a public health and safety perspective.
"Additionally, compensatory measures are in place to assure adequate monitoring capability is available to implement the CPNPP emergency plan in the unlikely event of challenges to the steam generator or fuel cladding. The N16 radiation monitor serves as a backup with alarm function and Radiation Protection technicians have been briefed on taking local readings with a Geiger-Mueller tube on MSL 2-02.
"Corrective actions are being pursued to restore 2-RE-2326 to functional status.
"The NRC Resident Inspector has been notified."
https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2018/20180216en.html