05000323/FIN-2018001-01

Finding

Title

Improper Troubleshooting Results in Reactor Trip Signal and Loss of Source Range Nuclear Instrument Power

Description

The inspectors reviewed a Green,self-revealed non-cited violation of Technical Specification 5.4.1.a Procedures, because PG&E personnel failed to follow the requirements of MA1.DC54, Conduct of Maintenance, Revision 15. Specifically, on March 20, 2018, with the reactor in Mode 3 during informal troubleshooting of high background count rate on source range nuclear instrument (NI) NI-32, PG&E personnel caused a short in NI cabinet B resulting in a blown fuse and the loss of power to the cabinet. This resulted in the loss of power to power range NI-42, intermediate range NI-36, source range NI-32, a reactor trip signal, a turbine trip signal, and all associated reactor protection interlocks. Power was automatically removed from the remaining source range NI due to reactor protection interlock P-10, resulting in no safety-related source range NI indication being available for control room operators.

01
Site:	Diablo Canyon
Report	IR 05000323/2018001 Section 1R20
Date counted	Mar 31, 2018 (2018Q1)
Type:	NCV: Green
cornerstone	Mitigating Systems
Identified by:	NRC identified
Inspection Procedure:	IP 71111.2
Inspectors (proximate)	C Newgent J Reynoso W Sifre L Brookhart N Greene J O'Donnell M Haire
Violation of:	Technical Specification - Procedures
INPO aspect	WP.1
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v • d • e

Finding - Diablo Canyon - IR 05000323/2018001

1(2)2(0)3(2)4(0)5(0)6(0)7(0)8(6)10(1)301(0)401(0)403(0)404(3)

IR 05000323/2018001: 1 2

Finding List (Diablo Canyon) @ 2018Q1

CCA Matrix: 2018Q1

	Q	CCA	Title
05000323/FIN-2017003-01	2017Q3	H.13	Inadequate Corrective Actions resulted in a Failure to Comply with Technical Specification 3.4.11 and an Emergency Declaration
05000323/FIN-2018001-02	2018Q1		Failure to Follow Operating Experience Procedures Results in Inadequate Screen of Operating Experience Report
05000323/FIN-2018001-01	2018Q1		Improper Troubleshooting Results in Reactor Trip Signal and Loss of Source Range Nuclear Instrument Power

Self-Identified List (Diablo Canyon)

[Diablo Canyon Findings full list]

05000323/FIN-2018001-01

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