ML111290179

Facility Overview, 03-22-11

ML111290179
Person / Time
Site:	Diablo Canyon
Issue date:	03/22/2011
From:	PG&E Corp
To:	Office of Nuclear Security and Incident Response
Mroz, Sara, NSIR/DPR, 301-415-1692
References
Download: ML111290179 (18)

Text

1 Diablo Canyon Power Plant Facility Overview March 22, 2011

2 Fukushima Daiichi Sequence of Events

• Large Earthquake caused automatic reactor shutdown and loss of offsite power

• Emergency diesel generators and other safety systems actuated

• Large tsunami wave (~1 hour later) disabled nearly all plant electrical and safety systems

• Remaining systems provided adequate core cooling for several hours, eventually became exhausted leading to core becoming uncovered and containment over pressurization

• Additionally, spent fuel pools heated up

3 Seismic/Tsunami Information Fukushima Daiichi License/Design Basis Fukushima Daiichi Reported DCPP License/Design Basis Ground Acceleration:

0.18 - 0.45 g Ground Acceleration:

0.2 - 0.51 g Ground Acceleration:

0.75 g Tsunami Wave Height:

6.5 m (~21 ft)

Tsunami Wave Height:

7 - 10 m (~23 - 33 ft)

Tsunami Wave Height:

~35 ft

4

• Auxiliary saltwater pump snorkels: ~45 ft

• Remaining equipment protected by 85 ft bluff

- Diesel Generators, Emergency Core Cooling, Electrical Switchgear

• Fresh water reservoirs: 310 ft

- Two 2.5 million gallon reservoirs

- Provide gravity-fed cooling water

• Steam Driven Auxiliary Feed Water Pumps

• Containment structures and spent fuel pools anchored to bedrock

• Six Diesel Generators; three per unit

- Generators designed with cross-ties to allow one generator to serve both units

• Two Underground diesel fuel storage tanks

- Minimum seven days of fuel for diesel generators

• On-site fire department, fire engines and equipment DCPP Critical Design and Safety Features

5

6 85 Power Block; Diesel Generators 310 Dry Cask Storage and Fresh Water Reservoirs

~45 Auxiliary Saltwater Snorkels 140 Surface of Spent Fuel Pools DCPP Elevations

7 115 Water Storage Tanks

8 Dry storage containers artists rendering

9 Used Fuel Storage Approximately 2,600 used fuel assemblies are stored on site Spent Fuel Pool

• Reinforced concrete structure

• Stainless steel plate liner

• Minimum of 23 ft of borated water over used fuel assemblies

• Emergency replacement water capability; including reservoir and water tanks

• Bottom of pool 16 ft below grade Dry Cask Storage

• Used fuel assemblies are stored in stainless steel Multi-Purpose Canister (MPC)

• Within a 20 ft tall Storage Overpack

10

11

12 Severe and Extreme Accident Response - Beyond Design Basis Severe and Extreme Accident Response - Beyond Design Basis Severe Accident Management Guidelines (SAMG)

• Controlling Reactor Coolant System (RCS) pressure and temperature

• Injecting into Steam Generators

• Controlling containment pressure and hydrogen concentration

• Flooding containment Extreme Damage Mitigation Guidelines (EDMG) - Actions taken to address extensive plant damage

• Spent Fuel Pool (SFP) water replacement and spray via fire water and portable pump (fire truck)

• Depressurization of steam generators using atmospheric dump valves

• Ability to reduce containment pressure even with no power or air available

• Start emergency diesel generators with no power available Severe Accident Management Guidelines (SAMG)

• Controlling Reactor Coolant System (RCS) pressure and temperature

• Injecting into Steam Generators

• Controlling containment pressure and hydrogen concentration

• Flooding containment Extreme Damage Mitigation Guidelines (EDMG) - Actions taken to address extensive plant damage

• Spent Fuel Pool (SFP) water replacement and spray via fire water and portable pump (fire truck)

• Depressurization of steam generators using atmospheric dump valves

• Ability to reduce containment pressure even with no power or air available

• Start emergency diesel generators with no power available

13 Additional Organizational Capabilities Additional Organizational Capabilities Long Term Seismic Program

• Dedicated geosciences department

• Ongoing seismic studies and analysis Onsite Fire Department

• Minimum of five personnel on site 24/7

• Two fire engines Recurring Emergency Preparedness Training

• Four Emergency Response Organization (ERO) teams

• Dedicated on-site and off-site emergency response facilities

• Periodic table-top and full-scope drills (minimum of four annually)

Long Term Seismic Program

• Dedicated geosciences department

• Ongoing seismic studies and analysis Onsite Fire Department

• Minimum of five personnel on site 24/7

• Two fire engines Recurring Emergency Preparedness Training

• Four Emergency Response Organization (ERO) teams

• Dedicated on-site and off-site emergency response facilities

• Periodic table-top and full-scope drills (minimum of four annually)

14 Prompt Industry Response INPO Event Report Actions provide near-term assurance that each station is in a high state of readiness to respond to both design basis and beyond design basis events. INPO 2011

• DCPP is verifying the capability to respond to:

- Beyond design basis events - due March 23

• Security threats

• Severe action management scenarios

- Station blackout (loss of AC power) - due March 30

- Internal and external flooding - due April 6

- Respond to a fire or flood with a seismic event - due April 13

• The Chief Nuclear Officers (CNO), working with INPO, formed a working group to look at additional short-term items, including station blackout equipment and Spent Fuel Pool equipment and contingencies

15 Conclusion

• DCPPs critical equipment is protected from flooding by elevations far above the maximum postulated tsunami wave height

• DCPP has robust and redundant emergency back up power capabilities

• DCPP stores five million gallons of water that constitutes a unique source of replacement cooling water supplied by gravity and does not rely on AC power

• Fault structures offshore in the vicinity of DCPP are not a significant tsunami source

• DCPP is reconfirming capability of equipment, procedures, training and contracts to respond to beyond design basis

• DCPP is committed to learning from the Fukushima Daiichi accident

16 Diablo Canyon Power Plant Additional Background Information

17 Diablo Canyon Power Plant Key Facts

• 2,300 MW of generating capacity -

approximately 18,000 GWh of electricity annually

• Two Pressurized Water Reactors (PWR)

• Located on approximately 12,000 acres of land, much of it preserved in its natural state

• Provides approximately 24% of the electricity to serve PG&Es customers

• Largest private employer in the county with over 1,300 jobs

• Largest taxpayer in San Luis Obispo County in 2009 - Approx. $24 million with

$15 million going to educational institutions

• In 2009, DCPP contributed $966.8 million of economic impact to the local economy Diablo Canyon provides clean, affordable and reliable electricity for more than three million northern and central California homes and businesses -

with almost zero greenhouse gas emissions

18 Significant Upgrades at Diablo Canyon PG&E has invested over $1 billion in improvements since it began operating in the mid 1980s. Some of these changes include:

• Added 6th on-site diesel generator and increased volume of diesel gas fuel tanks to seven day supply

• Added capacitor banks to the 230 kV offsite power source to improve reliability

• Replaced 500 kV offsite power source circuit breakers to increase earthquake resistance

• Replaced offsite power source transformers

• Replaced reactor heads and steam generators with new designs that are more resistant to corrosion

• Replaced plant process computer

• Upgraded residual heat removal system piping to reduce potential flow induced erosion following an accident

• Replaced emergency core cooling system flow orifices

• Developed additional procedures to address potential natural and manmade disasters

• Implemented significant site changes to improve plant security

• Implemented procedures and training to improve human performance