22 août 2013
Mise à l’arrêt du réacteur suite à l’apparition d’une fuite de liquide réfrigérant du circuit primaire supérieure à 230 litres par heure.
Type : PWR - Première divergence : 12 1976 - Puissance : 3459 MWTh -
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La fuite localisée de façon imprécise dans la zone du pressuriseur a évolué à 909 litres par heure.
La pression interne a dépassé les critères prescrits avec une pointe supérieure de 10 % au maximum autorisé : cette pression a été rétablie dans les limites prescrites après 1 heure et 37 minutes.
La vanne défectueuse à l’origine du problème avait été remplacée 4 mois plus tôt...
Event Number : 49300 - Facility : SALEM - State : NJ - Unit : [1] - RX Type : [1] - Event Date : 08/22/2013 - Event Time : 16:26
Emergency Class : NON EMERGENCY 10 CFR Section : 50.72(b)(2)(i) - PLANT S/D REQD BY TS
Initial PWR : 100 % Current PWR : 81 % Availa Event Text
UNIT 1 COMMENCED A TS REQUIRED SHUTDOWN DUE TO UNIDENTIFIED RCS LEAKAGE
"Salem Unit 1 has initiated a unit shutdown in accordance with TS (Technical Specification) Action Statement 3.4.6.2(b) for unidentified leakage greater than 1 gpm [gallon per minute] (Entered on 8/22/13 at 1029 EDT). TS 3.4.6.2 Action Statement (b) requires a reduction of leakage rate to within limits within 4 hrs. or be in at least Hot Standby within the following 6 hours. Initial investigation has indicated that the leakage source is from packing on Pressurizer Spray Valve 1PS1 located in the RCS [Reactor Coolant System] Pressurizer shroud area inside Containment. Unidentified leakage is currently indicating 4 gpm. NRC Resident [Inspector] has been notified. Manual isolation is in progress.
"Additionally, TS Action Statement 3.6.1.4 Primary Containment Internal Pressure was entered at 1510 [EDT] for exceeding 0.3 psig. Action requires restoration of containment pressure to within specification in 1 hour or be in hot standby within the next 6 hours. Containment pressure was restored to less than 0.3 psig at 1647 [EDT] and TS 3.6.1.4 was exited. Peak containment pressure reached [was] 0.33 psig.
"Location of leak : Unit 1 RCS (containment), Pressurizer, 1PS1 Pressurizer Spray Valve Packing "Time & date leak started : 1019 [EDT] on 08/22/2013 "Leak rate : 4 gpm, T/S leak limits : 1 gpm "Last known coolant activity : Primary (DEI [Dose Equivalent Iodine]-microCuries/cc) 5.973E-5 microCuries/cc "Secondary (gbg [Gross Beta Gamma]-microcuries/cc) < LLD [Lower Limit of Detectability] "Was this leak a sudden or long-term development ? Sudden"
The licensee is reducing power at 30%/hour and anticipates entering Mode 3 in approximately 3 hours. The 1PS1 Pressurizer Spray Valve was replaced and the air operator rebuilt during the last refueling outage in April/May of 2013.
The licensee informed the State of New Jersey and will 9inform the Lower Alloways Creek [LAC] Township.
Source : https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2013/20130823en.html
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