05000275/FIN-2010006-02

Finding

Title

Failure to Maintain Proficiency of Operators to Meet the Time Critical Operator Actions

Description

The team identified a noncited violation of 10 CFR Part 50, Appendix B, Criterion III, Design Control, involving the failure to ensure that operators are able to implement specified actions in response to operational events and accidents. Specifically, operators could not achieve actions within the analysis time estimates for the cold leg recirculation phase of a loss of coolant accident response and the steam generator tube rupture response as described in the licensees safety analysis report. The finding is more than minor because it affected the Mitigating Systems Cornerstone objective of ensuring the availability, reliability, and capability of systems that respond to initiating events to prevent undesirable consequences. The finding represented a potential loss of a safety function requiring a Phase 2 analysis. Because the probability of human error is not effectively addressed by a Phase 2 analysis, a Phase 3 analysis was performed. The senior reactor analyst reviewed the actual timing of the walkdowns associated with the steam generator tube rupture time critical actions. The analyst determined that, while the licensee failed to meet the specific cooldown timing documented in the Final Safety Analysis Report, the total time to start cooling the reactor was well within the total critical timing of the event. The analyst found no impact on safety in delaying the cooldown of the reactor for one minute given that the other time critical actions were performed more quickly than required. Therefore, the analyst determined that this portion of the finding was of very low safety significance because it does not represent an actual loss of safety function (Green). The senior reactor analyst reviewed the issue related to the assumed action times associated with switching over to containment sump recirculation lineup for their emergency core cooling system pumps during a large break loss of coolant accident. The analyst noted that this time critical action was only required if a large-break loss of coolant accident occurred simultaneously with the failure of an residual heat removal pump to stop automatically, requiring local isolation of the pump. Given that the frequency of the initial conditions for the time critical action are below the Green/White threshold, the change in core damage frequency associated with this finding must be of very low safety significance (Green). The team determined that the finding was reflective of current plant performance because the licensee participated in a recent industrywide study on time critical operator actions, but did not implement any of the groups recommendations. The finding had a crosscutting aspect in the area of human performance, decision making, because the licensee did not use conservative assumptions in the decision making process related to verifying the validity of the underlying assumptions used to evaluate the feasibility of operators implementing time critical operator actions

02
Site:	Diablo Canyon
Report	IR 05000275/2010006 Section 4OA2
Date counted	Sep 30, 2010 (2010Q3)
Type:	NCV: Green
cornerstone	Mitigating Systems
Identified by:	NRC identified
Inspection Procedure:	IP 71152
Inspectors (proximate)	R Taylor T Brown M Hay A Fairbanks S Hedger
CCA	H.14, Conservative Bias
INPO aspect	DM.2
'
v • d • e

Finding - Diablo Canyon - IR 05000275/2010006

1(0)2(6)3(4)4(5)5(12)6(5)7(11)8(0)201(7)301(0)402(2)403(2)501(0)28(0)

IR 05000275/2010006: 1 2 3 4 5

Finding List (Diablo Canyon) @ 2010Q3

CCA Matrix: 2010Q3

	Q	CCA	Title
05000275/FIN-2009005-04	2009Q4	P.1 P.1(a)	Less than Adequate Replacement Reactor Head Modification Design Control
05000275/FIN-2009005-01	2009Q4	H.4 H.9	Less Than Adequate Work Planning Resulted in the Release of Two Gas Decay Tanks
05000275/FIN-2009005-03	2009Q4	P.2	Inadequate 50.59 Evaluation for Steam Generator Tube Rupture Analysis
05000275/FIN-2009005-05	2009Q4	P.2	Less than Adequate Change Evaluation to the Facility as Described in the Final Safety Analysis Report Update
05000275/FIN-2009005-02	2009Q4	H.5	Failure to Properly Plan a Maintenance Activity
05000275/FIN-2010002-04	2010Q1	P.2	Less Than Adequate Evaluation Following a Failure of Both Motor Driven Auxiliary Feedwater Trains
05000275/FIN-2010402-02	2010Q1		Security
05000275/FIN-2010402-01	2010Q1		Security
05000275/FIN-2010002-01	2010Q1	P.3	Failure to Effectively Implement the Seismically-Induced Systems Interaction Program
05000275/FIN-2010002-05	2010Q1	P.2	Failure to Submit a LERE for a Common-Cause Inoperability of Independent Trains or Channels
05000275/FIN-2010002-03	2010Q1		Failure to Report a Condition That Could Have Prevented the Fulfillment of a Safety Function
05000323/FIN-2009009-03	2010Q1	P.2	Failure to Evaluate a Change to the Facility as Described in the Final Safety Analysis Report Update Associated with the Addition of Manual Actions in the Safety Analysis
05000275/FIN-2010002-02	2010Q1	P.2	Failure to Update the Final Safety Analysis Report with the Current Plant Design Bases
05000323/FIN-2009009-02	2010Q1	P.2 P.1(a)	Failure to Conduct an Adequate Post-Modification Test
05000323/FIN-2009009-01	2010Q1	P.2	Failure to Follow Design and Configuration Control Requirements
05000275/FIN-2010003-03	2010Q2	P.2	Failure to Report a Condition that Could Have Prevented the Fulfillment of a Safety Function
05000275/FIN-2010007-03	2010Q2	H.14	Non-Conservative Decision Making resulted in a Violation of Technical Specification
05000275/FIN-2010007-05	2010Q2	P.2	Inadequate Operability Determination Associated With the Offsite Degraded Voltage Protection Scheme
05000275/FIN-2010007-06	2010Q2		Second Level Undervoltage Relay Time Delay to Initiate Load Shed and Sequencing Upon the Diesel Generator is Adequate to Assure Plant Safety
05000275/FIN-2010007-08	2010Q2	P.2	Inadequate Drawings and Procedures to Align Emergency Makeup Water Supply from Diablo Canyon Creek to Support the Auxiliary Feedwater System
05000275/FIN-2010003-01	2010Q2	P.2	Failure to Perform Unit 1 Containment Concrete Inspections
05000275/FIN-2010003-02	2010Q2		Inadequate Corrective Actions Following Identification of a Nonconservative Technical Specification
05000275/FIN-2010007-07	2010Q2		Nonconservative Inputs into Motor Operated Valve Calculation
05000275/FIN-2010007-10	2010Q2		Failure to Update Text to Reflect Credited Design Class I Makeup Flowpath to Component Cooling Water Expansion Tank in the Final Safety Analysis Report Update
05000275/FIN-2010007-09	2010Q2		Failure to Update Feedwater Rupture Accident Analysis in the Final Safety Analysis Report Update
05000275/FIN-2010007-04	2010Q2	P.2	Failure to Update the Final Safety Analysis Report Update with the Current Plant Design Bases Section
05000275/FIN-2010007-02	2010Q2	P.2	Failure to Adequately Evaluate Changes to the Diesel Testing as Described in the Final Safety Analysis Report Update
05000275/FIN-2010007-01	2010Q2	H.14	Less than Adequate Change Evaluation to the Facility as Described in the Final Safety Analysis Report Update
05000275/FIN-2010201-03	2010Q3	P.6	Security
05000275/FIN-2010201-02	2010Q3	H.12	Security
05000275/FIN-2010004-05	2010Q3		Inadequate Design Control for the Auxiliary Saltwater System
05000275/FIN-2010004-04	2010Q3	P.2	Inadequate Operability Determination
05000275/FIN-2010004-03	2010Q3	H.8	Inadequate Risk Assessment during Planned Maintenance Activities
05000275/FIN-2010004-02	2010Q3	P.3	Inadequate Risk Management during a Planned Auxiliary Saltwater Pump Outage
05000275/FIN-2010004-01	2010Q3	P.1	Failure to Identify a Degraded Fire Barrier
05000275/FIN-2010201-07	2010Q3		Security
05000275/FIN-2010201-06	2010Q3		Security
05000275/FIN-2010201-05	2010Q3		Security
05000275/FIN-2010403-02	2010Q3		Security
05000275/FIN-2010403-01	2010Q3	P.1	Security
05000275/FIN-2010201-04	2010Q3		Security
05000275/FIN-2010006-05	2010Q3	P.2	Failure to Appropriately Evaluate Failed Residual Heat Removal Surveillance Test
05000275/FIN-2010201-01	2010Q3	H.14	Security
05000275/FIN-2010006-04	2010Q3	H.14	Untimely and Inadequate Corrective Actions for the Emergency Diesel Generators
05000275/FIN-2010006-02	2010Q3	H.14	Failure to Maintain Proficiency of Operators to Meet the Time Critical Operator Actions
05000275/FIN-2010006-01	2010Q3	H.14	Inadequate Design Control for the Emergency Diesel Generator
05000275/FIN-2010006-03	2010Q3	P.2	Failure to Submit Complete and Accurate Information for a Requested License Amendment

Self-Identified List (Diablo Canyon)

	Q	Title
05000275/FIN-2009403-01	2009Q4	Licensee-Identified Violation
05000275/FIN-2009005-06	2009Q4	Licensee-Identified Violation
05000275/FIN-2010002-06	2010Q1	Licensee-Identified Violation
05000275/FIN-2010007-11	2010Q2	Licensee-Identified Violation
05000275/FIN-2010003-04	2010Q2	Licensee-Identified Violation

[Diablo Canyon Findings full list]

05000275/FIN-2010006-02

Navigation menu

Search