Junk Plant Columbia:More Coponents Fail During Lastest Hard Scram

Why wasn't this picked up during normal testing and inspections?

Power Reactor	Event Number: 52443
Facility: COLUMBIA GENERATING STATION Region: 4 State: WA Unit: [2] [ ] [ ] RX Type: [2] GE-5 NRC Notified By: DAVID PORTER HQ OPS Officer: BETHANY CECERE	Notification Date: 12/19/2016 Notification Time: 07:39 [ET] Event Date: 12/18/2016 Event Time: 23:20 [PST] Last Update Date: 12/19/2016
Emergency Class: NON EMERGENCY 10 CFR Section: 50.72(b)(3)(v)(D) - ACCIDENT MITIGATION 50.72(b)(3)(ii)(A) - DEGRADED CONDITION	Person (Organization): RAY KELLAR (R4DO)

Unit	SCRAM Code	RX CRIT	Initial PWR	Initial RX Mode	Current PWR	Current RX Mode
2	N	N	0	Hot Shutdown	0	Hot Shutdown

Event Text

UNISOLABLE LEAK ON HIGH PRESSURE CORE SPRAY "On December 18, 2016 at 2320 [PST], a leak was discovered on the High Pressure Core Spray (HPCS) system minimum flow line. The leak is located at a bolted flange downstream of the manual isolation valve HPCS-V-53. The location of the leak is not isolable from the suppression pool. This provides a direct path from inside the Primary Containment to the Reactor Building. "High Pressure Core Spray system is a single train Emergency Core Cooling System (ECCS) system, therefore inoperability is reportable per 10 CFR 50.72(b)(3)(v)(D). "Based on the location of the leak, Primary Containment integrity is compromised. Primary Containment was declared inoperable and is reportable per 10 CFR 50.72(b)(3)(ii)(A). "The cause of the leak is under investigation. Actions are underway to cool down and enter MODE 4." The licensee has notified the NRC Resident Inspector.