DCPP Performance Based on NRC Performance Indicators January 2016 - June 2016 Hossein Hamzehee Manager, Regulatory Services PG&E June 22, 2016

DCPP Performance Overview Diablo Canyon is rigorously inspected by the Nuclear Regulatory Commission (NRC). PG&E is committed to the highest safety standards and we continually re-evaluate our operations and emergency plans. We never stop examining our plans and take actions to ensure that we are ready to meet our mission to protect public health and safety.

DCPP Performance Summary January 2016 – June 2016 Summary: This presentation covers approximately 5 months of NRC inspections involving ~3000 hours of inspection time. DCPP met “Green” performance expectations for all NRC performance indicators. Eight very low-safety significant violations were identified since the last DCISC meeting in February 2016.

NRC Performance Indicators Unit 1 Unit 2 G Unplanned Scrams per 7000 Critical Hrs Unplanned Power Changes per 7000 Critical Hrs Unplanned Scrams with Complications Safety System Functional Failures Mitigating Systems Performance Index, Emergency AC Power System Mitigating Systems Performance Index, High Pressure Injection System Mitigating Systems Performance Index, Heat Removal System Mitigating Systems Performance Index, Residual Heat Removal System G Mitigating Systems Performance Index, Cooling Water Systems Reactor Coolant System Activity Reactor Coolant System Leakage Drill/Exercise Performance ERO Drill Participation Alert & Notification System Occupational Exposure Control Effectiveness RETS/ODCM Radiological Effluent

Licensee Event Reports No new Licensee Event Reports (LER) were issued during January 2016 through June 2016. Supplemental information was provided to the NRC in February 2016 regarding a 2014 LER related to a Residual Heat Removal socket weld issue.

Safety Significance: What do colors mean? Safety significance characterizations are either Green (very low), White (low to moderate) Yellow (substantial) or Red (high). Green non-cited violations indicate very low safety significance, with no impact to public health and safety.

NRC Violations January 2016– June 2016 Eight non-cited violations since last DCISC public meeting All are Green – Very low safety significance with no impact to public health & safety Examples: Failure to evaluate the extent of condition of a nonsafety-related breaker, which was procured as safety-related, in accordance with plant procedure. (Cross-Cutting Aspect H.14 Conservative Bias) Failure to correct the lack of design verification of 460 Volt motors at maximum allowed frequency when powered from Emergency Diesel Generator. (Cross-Cutting Aspect P.2 Evaluation) Procedure Inadequacy identified in Emergency Operating Procedure for isolating a faulted steam generator. (Cross-Cutting Aspect H.1 Resources) DCPP overall performance is Green with respect to NRC Cross-Cutting aspects, except H.6 (Design Margins) which is White with 3 CCAs identified during recent Component Design Basis Inspection. 1. Non-Cited Violation (NCV) (Green) – Failure to verify design operational parameters associated with 125 VAC and 480 VAC equipment room ventilation systems. (No Cross-Cutting Aspect) Very low safety significance with no impact to public health & safety 2. NCV (Green) – Failure to evaluate the extent of condition of a nonsafety-related breaker, which was procured as safety-related, in accordance with plant procedure. (Cross-Cutting Aspect H.14 Conservative Bias) 3. NCV (Green) – Failure to ensure DC components acceptable up to max battery equalizing voltage. (Cross-Cutting Aspect H.6 Design Margins) 4. NCV (Green) – Failure to verify the design of the 230 kV preferred offsite power source bounds postulated events. (Cross-Cutting Aspect H.6 Design Margins) 5. NCV (Green) – Failure to include appropriate quantitative acceptance criteria to ensure that the load tap changer speed for standby startup transformer was adequate to restore vital bus voltages to the required level during design basis events. (Cross-Cutting Aspect H.6 Design Margins) 6. NCV (Green) – Failure to comply with manufacturers instruction for maximum trip current settings of instantaneous mag trip circuit breakers and motor control center motor starter cubicles. (No Cross-Cutting Aspect) 7. NCV (Green) – Failure to correct the lack of design verification of 460 Volt motors at maximum allowed frequency when powered from Emergency Diesel Generator. (Cross-Cutting Aspect P.2 Evaluation) 8. NCV (Green) – Procedure Inadequacy identified in Emergency Operating Procedure for isolating a faulted steam generator. (Cross-Cutting Aspect H.1 Resources )

DCPP Performance Summary January 2016- June 2016 The following Inspection Reports were Issued: 1st Quarter Integrated Inspection Report (2016-001, 4/26/16) Component Design Basis Inspection Report (2016-007, 4/21/16) NRC Licensed Operator Examination Report (2016-301, 6/7/16) DCPP performance was Green based on NRC performance indicators.

Thank You Hossein Hamzehee