ML12026A459

EDG Ifr

ML12026A459
Person / Time
Site:	Seabrook
Issue date:	01/26/2012
From:	Robert Wolfgang Component Performance and Testing Branch
To:
Wolfgang R, NRR/DE/EPTB, 415-1624
References
Download: ML12026A459 (14)

Text

EDG Activities Bob Wolfgang Division of Engineering Component Performance and Testing Branch NOT NRC POLICY OR POSITION

Regulatory Guide 1.137, Fuel Oil Systems for Emergency Power Supplies

• Reg. Guide being revised by Office of New Reactors

• Adding gas turbine generators

• Adding information on ULSD

• Adding information on biodiesel

• Updating referenced standards

Preliminary OpE Insights for 2011

• Increase in EDG issues related to inadequate bolt torquing 3

Voltage and Frequency

• The Standard Technical Specifications contain Surveillance Requirements that verifyy diesel generator g voltageg and frequency. Specifically, SR 3.8.1.7 has the following:

- Frequency is allowed to vary + 2%

• 58.8 Hz - 61.2 Hz

- Voltage is allowed to vary up to + 10% (rounded to the nearest 10 volts)

• 3740 V - 4580 V (for a 4160 V system)

PWROG Proposal

• Account for the capability of the control systems, i.e., governor and voltage regulator to control around those nominal values.

• Treat the tolerance as an uncertainty, similar to an instrument setpoint, and perform an uncertainty calculation which considers the specified tolerance, measurement and test instrument uncertainties, and setting tolerances.

PWROG Proposal Changes to IST Requirements to Address DG Voltage/Frequency Variations Original Maximum Allowable Pump Head Adjusted Maximum Allowable Pump Head Pump Head Original Minimum Allowable Pump Head Adjusted Minimum Allowable Pump Head Pump Flow

Issues

• Establish basis for minimum and maximum acceptable voltage

• Ensure valve stroke time and torque are acceptable

• Ensure pumps can start, run and have adequate capability (Safety Analyses)

• Loads that are not disconnected continue to operate after voltage drop during large motor start

Technical Specification Task Force TSTF 501

• Relocate stored fuel oil and lube oil volume values to licensee control

• Minor changes in volume requirements (e.g. ULSD) without NRC approval

SBO Background

• The NRC SBO rule (10 CFR 50.63) requires that each nuclear power plant must be able to cool the reactor core and maintain containment integrity for a specified duration of SBO

• RG 1.155, 1 155 Station Station Blackout Blackout, describes an acceptable means to comply with 10 CFR 50.63

• The method described in RG 1.155 results in a minimum acceptable SBO duration capability ranging from 2 to 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br />

• The result for all operating plants was a coping duration of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> max. ( Refer NUMARC 87-00)

• EDG Reliability was a factor to attain 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> coping duration

Fukushima Actions

• Recommendation 4

• The Task Force recommends that the NRCC strengthen S SBOO mitigation capability at all operating and new reactors for design-basis and beyond-design-basis external events

Task Force Recommendations

• Initiate rulemaking to revise 10 CFR 50.63 to require each operating and new reactor licensee to:

( ) establish a minimum coping (1) p g time of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> for a loss of all ac power- may entail small AC source (2) establish the equipment, procedures, and training necessary to implement an extended loss of all AC coping time of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> for core and spent fuel pool cooling and for reactor coolant system and primary containment integrity as needed (3) preplan and pre-stage offsite resources to support uninterrupted core and spent fuel pool cooling

License Amendment Requests For Allowed Outage Time

• LCO 3.8.1 requires:

- b. Two diesel generators capable of supplying the onsite Class 1E power distribution subsystem(s)

- ACTION: Restore DG to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />

• Staff extending the LCO to maximum 14 days with compensatory actions and AAC power source

• Need PRA and deterministic submittal

EDG Testing Survey Temporary Instruction 2515/176, Emergency Diesel Generator Technical Specification Surveillance Requirements Regarding Endurance and Margin Testing Testing (ML080420064)

• Staff Evaluating:

1) Consistency in testing requirements

2) Test Load to envelope postulated accident load

3) R.G. 1.9 allows 90% of continuous rating

Q Questions ti 14