Fukushima Response

1
Fukushima Response

• George Attarian
• 1/21/2013

2
Fukushima Response

• Timeline
• March 11 Event occurred
• March 18 INPO IER 11-1 issued (April 15)
• March 23 NRC TI 2515/183 issued (May 13)
• April 25 INPO IER 11-2 issued (September 20)
• April 19 NRC TI 2515/184 issued (June 30)
• May 11 NRC Bulletin 2011-01 issued (July 11)
• June 8 NEI The Way Forward issued
• July 12 NRC NTTF issued
• August 1 INPO IER 11-4 issued (January 28)
• August 1 INPO Equipment Survey issued (November
  4)

3
Fukushima Response

• Timeline
• September 1 INPO IER 11-1 Supplement issued
  (March)
• September 9 NRC SECY-11-0124 issued, SRM
  issued October 18
• October 3 NRC SECY-11-0137 issued, SRM
  issued November 8
• December 14 NRC holds first public, issue
  specific meetings on
  SECY-11-0137
• January 18-19NRC holds second public issue
  specific meetings and
  presents draft 50.54(f) letter with enclosures
• March 9 50.54(f) letter and enclosures
  and Orders issued to
  the Licensee for Tier I NTTFs

4
Fukushima Response

• NRC Near Term Task Force (NTTF) Recommendations
  (12)
• Clarifying The Regulatory Framework (1)
• Ensuring Protection (2)
• Enhancing Mitigation (5)
• Strengthening Emergency Preparedness (3)
• Improving the Efficiency of NRC Programs (1)

5
Fukushima Response

• NTTF Impact
• NTTF 2.1 Flood and Seismic
• 50.54(f) letter to licensee
• New flood analysis beyond design basis
• Seismic currently following GI 199
• NTTF 2.3 Walkdowns
• 50.54(f) letter to licensee
• Walk down the site for all external design basis
  events flood seismic, other external events
• NTTF 4.1 SBO
• Rule making

6
Fukushima Response

• NTTF Impact
• NTTF 4.2
• By order
• Additional pumps and related equipment
• FLEX approach
• NTTF 5.1 Harden Vents
• By order
• BWR Mark I II only
• Filtration system not in order
• NTTF 7.1 Spent Fuel Pool Instrumentation
• By order
• Level only
• Primary and backup
• Control Room or Alternate Shutdown monitoring
• Qualifications

7
Fukushima Response

• NTTF Impact
• NTTF 8 EDMG EOP SAMG integration
• Rule making
• NTTF 9.3 Emergency Preparedness Staffing
• 50.54(f) letter to licensee
• Extension of the EP Rule
• Staffing impact to multiple Unit plant sites
• Communication guidance

8
Station Blackout Definition

• 10CFR50.2 Definition
• The complete loss of alternating current (ac)
  electric power to the essential and nonessential
  switchgear buses in a nuclear power plant.
• Station blackout does not include the loss of
  available buses fed by station batteries through
  inverters or by alternate ac sources as defined,
  nor does it assume a concurrent single failure or
  design basis accident.

9
Alternate AC Sources

• An alternating current (ac) power source that is
  available to and located at or nearby a nuclear
  power plant and meets the following requirements
• Is connectable to but not normally connected to
  the offsite or onsite emergency ac power systems
• Has minimum potential for common mode failure
  with offsite power or the onsite emergency ac
  power sources
• Is available in a timely manner after the onset
  of station blackout and
• Has sufficient capacity and reliability for
  operation of all systems required for coping with
  station blackout and for the time required to
  bring and maintain the plant in safe shutdown
  (non-design basis accident)

10
Current NRC Rule

• 10CFR 50.63 Loss of all alternating current power
• (a) Requirements. (1) Each light-water-cooled
  nuclear power plant licensed to operate must be
  able to withstand for a specified duration and
  recover from a station blackout as defined in
  50.2. The specified station blackout duration
  shall be based on the following factors
• (i) The redundancy of the onsite emergency ac
  power sources
• (ii) The reliability of the onsite emergency ac
  power sources
• (iii) The expected frequency of loss of offsite
  power and
• (iv) The probable time needed to restore offsite
  power.

11
Current NRC Rule (contd)

• (2) The reactor core and associated coolant,
  control, and protection systems, including
  station batteries and any other necessary support
  systems, must provide sufficient capacity and
  capability to ensure that the core is cooled and
  appropriate containment integrity is maintained
  in the event of a station blackout for the
  specified duration.
• The capability for coping with a station blackout
  of specified duration shall be determined by an
  appropriate coping analysis. Licensees are
  expected to have the baseline assumptions,
  analyses, and related information used in their
  coping evaluations available for NRC review.

12
Regulatory Guide 1.155

• Reg. Guide 1.155, Station Blackout
• Specifies a method acceptable to the NRC staff
  for complying with 10CFR50.63
• Twenty four pages of detailed guidance
• EDG Target Reliability Levels
• Restoration of Offsite Power
• Ability to Cope with a Station Blackout
• Quality Assurance Guidance for Non-Safety Systems
  and Equipment

13
NUMARC 87-00

• Guidelines and Methodologies for Implementing the
  Nuclear Management an Resources Council (NUMARC)
  Station Blackout Initiatives
• Three Hundred Pages of Detailed Guidance,
  Examples, Topical Reports, and Questions
  Answers
• Endorsed by Reg. Guide 1.155 as Acceptable
  Guidance for Compliance to 10CFR50.63
• Contains Detail Beyond Reg. Guide 1.155

14
Typical Results

• Plant Specific SBO Coping Analyses Produced
• Specifies How Long You Have to Cope Without AC
  Power
• Typically 4 or 8 hours
• Specifies How Coping is Achieved
• Batteries, alternate ac power, RCS leak rates,
  water sources, pumps, instrumentation control,
  etc.
• Requires Containment Isolation
• Typically Addresses Pre- Hurricane Preparations
  for Coastal Plants
• Excludes Concurrent Design Basis Events
• Assumes Restoration of at Least One Source of
  Offsite or Onsite AC Power is Successful Before
  the Coping Period Ends

15
Typical Limitations Beyond SBO Coping

• Battery Depletion
• Water Sources Run Out CST Inventory
• RCS Inventory Losses - PWR RCP Seal Leakage
• BWR Suppression Pool Heat-up Saturation
• Emergency Lighting Battery Packs Deplete
• Increasing Manual Actions for Available Personnel
  as SBO Time Increases

16
Beyond SBO Coping Strategies

• Medium Size Generators to Re-Energize Battery
  Chargers
• Emergency Engine Driven Pumps to Replenish Water
  Sources CST Make-up
• Medium Size Generators and Pumps to Restore RCP
  Seal Injection
• RCP Shutdown Seal Package Designs to Limit
  Leakage
• BWR Hardened Wetwell Venting Systems and
  Suppression Pool Make-up with Cool Water
• Helmet Mounted LED Lights for Personnel or Longer
  Lasting LED Emergency Lights
• Pre-Plan and Pre-Stage More Emergency Equipment
  to Make Manual Actions Easier and Train More
  Personnel to Use it

17
What is FLEX?

• Response to NRC Mitigating Strategies Order (EA
  12-049)
• Provides a diverse and flexible means to prevent
  fuel damage while maintaining containment
  function in beyond design basis external event
  conditions resulting in an
• Extended Loss of AC Power, and
• Loss of Normal Access to the Ultimate Heat Sink
• Objective
• Establish an essentially indefinite coping
  capability by relying upon installed equipment,
  onsite portable equipment, and pre-staged offsite
  resources

18
Diverse Flexible Coping Capability (FLEX)
Emergency Plans
SAMGs
Emergency Plans
Emergency Response
Diverse Flexible CopingStrategy (FLEX)
SAMGs
Increased Defense-in-Depth
SBO Coping Capability
SBO Coping Capability
Prevention of Fuel Damage
Design Basis External Events
Design Basis External Events
Protection of Plant Equipment
Current
Current plus FLEX
19
Tier 1 FLEX Approach
20
FLEX Mitigation Strategies

• FLEX employs a three phase approach
• Phase 1 - Initially cope by relying on installed
  plant equipment,
• Phase 2 - Transition from installed plant
  equipment to onsite FLEX equipment,
• Phase 3 - Obtain additional capability and
  redundancy from offsite equipment until power,
  water, and coolant injection systems are restored
  or commissioned.
• Diverse and flexible to enable deployment of the
  strategies for a range of initiating events and
  plant conditions

21
Representative High-level Example (BWR)

• Phase 1 Initial Coping Capability
• Use RCIC for RPV makeup from suppression pool
• Rely on DC Power for key instrumentation and
  controls
• Phase 2/3 Extended Coping Capability
• Charge battery to maintain DC power
• Use Reliable Hardened Vent for containment heat
  removal
• Provide extended RPV makeup with portable pump

22
Representative High-level Example (PWR)

• Phase 1 Initial Coping Capability
• Turbine-driven AFW for SG makeup from Condensate
  Storage Tank
• Rely on DC Power for key instrumentation and
  controls
• Phase 2/3 Extended Coping Capability
• Charge battery to maintain DC power
• Provide extended SG makeup with portable pump
• Provide RCS makeup with portable pump, as needed

23
NRC Advance Notice of Rule Making

• Rule Making Objectives
• What specific objectives should the SBO rule be
  designed to achieve?
• How should actions taken in the NTTF 4.2 be used?
• What regulatory approach to SBO mitigation that
  follows the conceptual approach outlined in NTTF
  4.1?
• How can regulatory action in NTTF 8.0 be best
  integrated with SBO?
• How can regulatory action in NTTF 5.1 be best
  integrated with SBO?
• How can regulatory action in NTTF 7.1 be best
  integrated with SBO?

24
NRC Advance Notice of Rule Making

• Relationship between 10CFR 50.63 and the new SBO
  rule
• Keep existing rule and supplement with scenarios
  that go beyond the existing rule.
• Integrate existing rule with new requirements
  into a new rule for SBO.
• Supersede the existing SBO rule with an
  enveloping rule.
• Comments have been submitted, ACRS meeting to be
  held.
• Ball in NRC court.