25th Annual Report, Volume II, Exhibit C, Diablo Canyon Nuclear Power Plant (DCPP) Operations

1.0 PG&E/DCPP Organizations

The DCPP organization chart is included as an attachment.

2.0 Summary of Diablo Canyon Operations

2.0.1 Capacity Factor

During the assessment period of July 1, 2014, through June 30, 2015, Diablo Canyon’s Combined “Capacity Factor” averaged 94.1% (Net Maximum Dependable Capacity). Capacity factor is the ratio of actual generation output during an operating period to its potential generation output during that period when operating continuously at Maximum Dependable Capacity.

Unit 1 Operating Summary

During the 12-month reporting period ending June 30, 2015 Unit 1’s Capacity Factor was 98.7% (Net Maximum Dependable Capacity). The table below includes descriptions of operating events that impacted Unit 1 generation.

Unit 1 Power Generation Events July 2014—June 2015

Date Type Reduced to Power Level Event
09/06/14–09/06/14 Outage    0% Manually-initiated outage to perform high-pressure spray-wash of electrical lightning arrestors.
12/05/14–12/09/14 Curtailment 52% Manually-initiated curtailment for ocean cooling water system tunnel cleaning.
12/05/14–12/06/14 Outage    0% Manually-initiated outage to perform high-pressure spray-wash of electrical lightning arrestors. Outage occurred during 12/05/14 to 12/09/14 tunnel cleaning curtailment.
12/18/14–12/31/14 Curtailment 93% Manually-initiated curtailment due to Feedwater Heater 1-5A tube leak.
12/31/14–01/04/15 Outage   0% Manually-initiated outage to repair Feedwater Heater 1-5A tube leak. Outage included emergent repair of Residual Heat Removal Valve 1-RV-8708 cracked socket weld.
05/29/14–05/29/15 Curtailment 87% Manually-initiated curtailment for STP M-21C Main Turbine Control Valve Test.

Unit 2 Operating Summary

During the 12-month reporting period ending June 30, 2015 Unit 2’s Capacity Factor was 89.5% (Net Maximum Dependable Capacity). This period included a refueling outage.

The table below includes descriptions of operating events that impacted Unit 2 generation.

Unit 2 Power Generation Events July 2014—June 2015

Date Type Reduced to Power Level Event
07/19/14–07/19/14 Outage   0% Manually-initiated maintenance outage to perform high-pressure spray-wash of electrical lightning arrestors.
08/14/14–08/18/14 Outage  0% Manually-initiated outage to repair Emergency Diesel Generator 2-3 broken bolt and Fuel Oil Booster Pump leak.
10/05/14–11/06/14 Refueling Outage  0% 2R18 refueling outage. Planned duration 33 days.
03/23/15–03/25/15 Curtailment 98% Manually-initiated curtailment to repair Feedwater 2-2B XS-2-LCV-32 controller.
05/08/15–05/08/15 Curtailment 88% Manually-initiated curtailment for STP M-21C Main Turbine Control Valve test.

2.0.2 Refueling Outages

The Unit 2 eighteenth refueling outage (2R18) was a significant outage, which included the following major work:

Outage 2R18 began on October 5, 2014 and ended on schedule on November 6, 2014. Outage goals and results were as follows:

Performance Category Goal Actual
Recordable & Disabling Injuries  0  0
Nuclear Safety Events  0  0
Human Performance Event Clock Resets  0  0
Outage Duration (Days) ≤33   33
Dose Goal (Rem) 30 30
Significant Foreign Material Events (FME)  0  0

2.0.3 Collective Radiation Dose Equivalent Exposures

The bulk of personnel radiation exposure occurs during refueling outages. For this reason, the total annual exposure is largely dependent upon the outage planning effectiveness, radiation levels, outage duration, number of outages conducted in the year and emergent maintenance activities. Collective radiation dose for Refueling Outage 2R18 was 30.3 person-Rem versus a goal of 31.0. Dose goals achieved can be attributed to radiation field reduction efforts and improved radiation workplace practices. Non-outage radiation doses typically amount to about eight person-Rem per year.

2.0.4 Unplanned Reactor Trips

PG&E’s goal is to have zero unplanned automatic reactor trips per unit per year while critical. Unnecessary reactor trips not only reduce plant capacity factor, but they also represent unnecessary challenges to safety systems and may indicate substandard operating or maintenance practices. Manual trips are not counted because PG&E believes that this may inhibit operator-initiated trips and actions to protect equipment. There were no unplanned automatic reactor trips in either unit during this reporting period.

2.0.5 Unplanned Safety System Actuations

This indicator is the sum of the number of unplanned emergency core cooling system (ECCS) actuations (whether the ECCS actuation set point has been reached or from a spurious or inadvertent ECCS signal) and the number of unplanned emergency AC power system actuations that result from the loss of power to a safeguards bus. For Diablo Canyon, ECCS actuations include actuations of the high-pressure injection system, the low-pressure injection system, or the accumulators. Such actuations should be avoided because the plant should be maintained in a safe configuration to preclude actuations, and unnecessary challenges to plant safety systems should be minimized. PG&E’s goal for this indicator continues to be no unplanned safety system actuations at DCPP. No actuations occurred during the reporting period.

2.0.6 Chemistry Effectiveness Indicator (CEI)

DCPP has adopted the industry Chemistry Effectiveness Indicator (CEI) to measure overall station chemistry effectiveness. The CEI includes metrics for the Primary Chemistry and the Secondary Chemistry and is a measure of chemical control as well as contaminant control. The CEI can range from 0 to 100 with a lower value demonstrating better chemistry control. Monthly CEI for Unit 1 for August 2015 was 0.000. Unit 1 18-month composite remains at 0.310 due to feedwater iron from 1R18 startup. This results in 2nd quartile performance (0.071 to 0.770) for all PWRs. DCPP expects this to drop to 0.000 in September 2015, returning to the 1st quartile. Monthly CEI for Unit 2 for August 2015 was 0.000. Unit 2 18-month composite remained at 0.000 keeping DCPP in the 1st quartile performance (≤0.070) for all PWRs.

2.0.7 Fuel Reliability

The purpose of the fuel reliability indicator is to monitor progress in achieving and maintaining high fuel integrity. Failed fuel represents a breach in the initial barrier for preventing offsite release of fission products. Such failure also has a detrimental effect on operations and increases the radiological hazards to plant workers.

Based on measurement of both steady-state reactor coolant activity and transient iodine spiking, PG&E determined that both Units 1 and 2 operated without any failed rods during the 12-month reporting period.  Unit 1 has operated without any failed rods since the beginning of Cycle 5. The Unit 2 radiochemistry data indicates that Unit 2 has been operating without fuel defects since starting up Cycle 17 (June 2011).

PG&E continues to follow its fuel reliability programs, including the aggressive preventive maintenance inspection of new and irradiated fuel, continued implementation of procedural guidelines to prevent fuel damage during both power and refueling operations, implementation of chemistry controls, fuel assembly reconstitution for identified rod failures, tracking and disposition of damaged fuel assemblies and strict controls to exclude foreign material from the reactor coolant system.

Organizational Charts

Senior Vice President Nuclear Generation and Chief Nuclear Officer

Senior Vice President Nuclear Generation and Chief Nuclear Officer

Vice President Nuclear Services

Vice President Nuclear Services

Vice President Nuclear Services

Vice President Nuclear Services

DCPP Station Director

DCPP Station Director


For more information contact:

Diablo Canyon Independent Safety Committee
Office of the Legal Counsel
857 Cass Street, Suite D, Monterey, California 93940
Telephone: in California call 800-439-4688; outside of California call 831-647-1044
Send E-mail to: dcsafety@dcisc.org.