Plant Process Computer (C95)

Question 1

What is the power supply for Plant Process Computers?

Answer 1

Equipment - SECURITY INVERTER with separate batter backup for HAL/SAL (primary/secondary computers)

Displays - Vital AC for both units

Question 2

What is the purpose of the Plant Process Computer?

Answer 2

Calculate CTP every 15 seconds and verify compliance with thermal limits

Question 3

What are the outputs for Power/Flow log, specifically UNITS?

Answer 3

Don’t forget pressure is measured in PSIA

PSIG = PSIA – 14.7

Don’t forget some measurements are in BTU/lbm

Question 4

What are the Thermal Limits displayed on the Process Computer?

Answer 4

MFLCPR – Should < 1.000
MFLPD – Should < 1.000
MAPRAT – Should < 1.00
PCRAT – Can > 1.00 with approval of RE

Question 5

What are the major thermal limits and their bases?

Answer 5

LHGR - LIMITS fuel pellet expansion to 1% plastic strain in a transient
Maximum Fraction of Limiting Power Density
MFLPD = LHGR/LHGRlim >1.0=violation

APLHGR - PREVENTS PCT from exceeding 2200F in a DBA LOCA
Maximum Average Planar Ratio
MAPRAT = APLHGR/APLHGRlim >1.0 = violation

MCPR - Ensures Transition Boiling is avoided in 99.9% of fuel bundles (0.1% may still have fuel damage)
Maximum Fraction Limiting Critical Power Ratio
MFLCPR = MCPRlim/ MCPR <1.0= violation

Question 6

When is the Crossflow correction factor enforced/not?

Answer 6

The Crossflow System shall be functional at thermal power >2777 MWt

If INOP - 72 hours to restore or <2777 MWt

Cannot put crossflow in service until >80% RTP. Automatically goes to CF of 1.0 if <80%.

Question 7

What are the 34GO-OPS-022, “Maintaining Rated Thermal Power” limits?

Answer 7

Applicable only >2690 MWt

Maximum licensed power level is 2804 MWt

Limited to 2777MWt if CROSSFLOW is out of service