Loss of Y-10

Question 1

How is AFAS affected by a loss of Y-10?

Answer 1

C-187A Channel is Lost

The channel goes to a tripped state. Logic = 1 out of 3 now.

Loss of power prevents the channel from being bypassed.

T.S. 3.3.3 Engineered Safety Features (ESF) Instrumentation

• Four ESF bistables and associated instrument channels for each Function in Table 3.3.3-1 shall be OPERABLE.

Question 2

How is CIAS impacted by the loss of Y-10?

Answer 2

Left channel CIAS is lost.

If actual CHR/CHP perform EOP Supplement 6 and isolate left channel valves for CHP or CHR.

Containment Spray on CHP requires left channel spray initiation.

SIAS initiation on CHP requires push button.

T.S. 3.3.3/3.3.4

3. 3.3 Engineered Safety Features (ESF) Instrumentation
   * Four ESF bistables and associated instrument channels for each Function in Table 3.3.3-1 shall be OPERABLE.
4. 3.4 Engineered Safety Features (ESF) Logic and Manual Initiation
   * Two ESF Manual Initiation and two ESF Actuation Logic channels and associated bypass removal channels shall be OPERABLE for each ESF Function specified in Table 3.3.4-1.

Question 3

How is CRHVAC impacted by the loss of Y-10?

Answer 3

Left ‘A’ Train can’t be operated in Emergency.

If Left ‘A’ Train running, swaps to recirculation mode.

If running, VC-11 trips and won’t restart.

T.S. 3.7.10/3.7.11

3.7.10 Control Room Ventilation (CRV) Filtration

• Two CRV Filtration trains shall be OPERABLE.
• MODES 1, 2, 3, 4,
• During CORE ALTERATIONS,
• During movement of irradiated fuel assemblies,
• During movement of a fuel cask in or over the Spent Fuel Pool (SFP).

3.7.11 Control Room Ventilation (CRV) Cooling

• Two CRV Cooling trains shall be OPERABLE
• MODES 1, 2, 3, 4,
• During CORE ALTERATIONS,
• During movement of irradiated fuel assemblies,
• During movement of a fuel cask in or over the Spent Fuel Pool (SFP).

Question 4

How does a loss of Y-10 impact the ADVs?

Answer 4

HIC-0780A, 0780B, 0781B Steam dump control at C-01 and C-33 no longer function.

Utilize TBV

T.S. 3.7.4 Atmospheric Dump Valves (ADVs)

One ADV per steam generator shall be OPERABLE.

MODES 1, 2, and 3,
MODE 4 when steam generator is being relied upon for heat removal

Question 5

How is ‘A’ Pressurizer Level Control impacted by a loss of Y-10?

Answer 5

Fails to max charging and no letdown with ‘A’ channel PLCS in service.