250vdc

Question 1

What is the purpose of 250VDC?

Answer 1

Provide power to large DC loads in RB & TB.

Question 2

What is the Design condition for the 250vdc battery?

Answer 2

Designed to start and carry normal DC loads requried for safe shutdown on one unit and operations required to limit the consequencyes of design basis event on the other unit for a period of 4 hours following loss of all AC sources (no power to chargers).

Question 3

What is the construction of the 250vdc battery?

Answer 3

120 cells in series with one dedicated charger and one swing charger.

Question 4

What is the TS limit for the 250vdc battery?

Answer 4

210vDC

Question 5

What is the power source for the Unit 2 250 vdc charger?

Answer 5

MCC 28-3

Question 6

What is the power source for the Unit 3 250vdc charger?

Answer 6

MCC 38-2

Question 7

What is the power source for the Unit 2/3 250vdc charger?

Answer 7

MCC 29-2 or 39-2

Question 8

What interlock exists on the U2/3 250vdc power source?

Answer 8

Key lock on supply breakers to prevent paralleling power source

Question 9

What is the normal configuration of the 250vdc battery system?

Answer 9

Unit charger supplies power to Unit TB MCC and Opposite Unit RB MCC A&B (U2 Charger supplies TB MCC 2 which supplies RB MCC 3A & 3B)

Question 10

What interlocks and limitations exist for the 250vdc battery?

Answer 10

Distribution panels have overcurrent protection
Grounding limitations (A+B+C)
Level 2: >183.6v with no buttons or > 215.5v w/either buttons
Level 3: >229.4 v w/no buttons or >244.1v w/either button
(A+B = C : Positive button + negative button = no button)

Question 11

What is the impact of a loss of 250VDC Bus?

Answer 11

Loss of associated MCCs for Unit TB and Opp Unit RB

Can put both units in a 2 hour TS LCO for shutdown

Question 12

What happens on loss of U2 250 VDC TB MCC 2?

Answer 12

Loss of Emergency H2 SOP
Loss of H2 and SWC Service Water Supply
Loss of TBCCW Hx Service Water Outlet Valves
Loss of ESS UPS

Question 13

What happens on loss of 250 vdc RB buses?

Answer 13

Loss of HPCI Aux Oil Pump and EBOP
Loss of HPCI Turning Gear and Steam Supply Valves
Loss of HPCI Suction and Discharge Valves
Loss of HPCI GSLO Condenser Exhauster and Hotwell Drain Pump
Loss of Isco Outboard steam and condensate vales and shell side make up vavles
Loss of all SDC Pump Suction Valves and Hx Isolation valves
Loss of RWCU Aux Pump Sustion and Bypass Valves

Question 14

What is purpose of NSR 250VDC BOP?

Answer 14

Provides power to non-safety related TB Loads.

Question 15

What is the only load on NSR 250vdc BOP?

Answer 15

Main Turbine EBOP

Question 16

Where is the 250vdc BOP system?

Answer 16

UNit 3 - It was modified to only have 1 system providing to both units

Question 17

What type of protection is provided to the 250vdc BOP system?

Answer 17

Dist Panels breakers have overcurrent protection only.

MCC 1A has Volt Meter and UV on it

Question 18

What chargers supply the 250vdc BOP system?

Answer 18

3A and 3B chargers

Question 19

What is the normal power source to the 250vdc BOP Battery system?

Answer 19

Bus 35 feeds charger 3A (same breaker as MCC 35-1)

Bus 36 feeds charger 3B (same breaker as MCC 36-1)