Shared Flashcard Set

Details

Salem 2013 SRO CERT
PZR Pressure and Level Control
19
Other
Professional
08/10/2013

Additional Other Flashcards

 


 

Cards

Term

PZR Pressure Instrumentation Purpose:

Definition

 

Pressurizer Pressure Control System
§Maintain Reactor Coolant System pressure
§Limit pressure changes during transients
§Prevent RCS from exceeding design pressure of 2485 psig
Term
PZR Pressure Design Basis:
Definition

 

Pressure Control System Design Criteria:
§The pressure control system is designed to prevent Rx trips under the following conditions:
§Ramp load change at +/- 5%/min, assuming automatic rod control
§Step load change of +/- 10%, between 15% and 100% power, assuming automatic rod control
§50% load rejection, assuming automatic rod control (10%) and steam dumps (40%)
 
Term
PZR Pressure Instrumentation Outputs:
Definition

 

Outputs:
§OT/DT (4) (122% minus penalty)
§PZR Low Press SI (3) (1765)
§PZR Low Press SI Block / Unblock (3) (P-11) (1915)
§High Press Rx Trip (4) (2385)
§Low Press Rx Trip (4) (1865*)
    * Rate Sensitive
 
Term

Components, Purpose and Setpoints:

PZR Heaters

Definition

Establish and maintain saturation temperature

§
§Variable – 415 KW , PWR GP 460 AC
§#21 BU – 415 KW , GP 460AV, emergency C VB
§#22 BU – 969 KW, EP 460 AC, emergency A VB
Variable:
Controlled by Master Pressure Controller 
<17% PZR level cutoff and OH E-36 “PZR HTR OFF LVL LO”
MPC 16% (2220psig) heaters- full on, start to modulate as pressure rises.
MPC 34% (2250psig) heaters off.
Back Up:
§MPC Output 9% (2210psig), breakers for 21 and 22 group will close in Auto.
OHA “PZR HTR ON PRESS LO” also energizes
§MPC Output of 14% (2218psig) the breakers will open if in Auto.
17% PZR Level will trip heaters off (same as Variable Group and same OHA)
Low Level Trip is bypassed when on Emergency Power
Heaters also energize on a PZR level increase 5% above programmed level.
OHA E-20 PZR HTR ON LVL HI
 
Term

Components, Purpose and Setpoints:

PZR Spray

Definition

 

Reduce pressure by spraying water from cold legs into the PZR vapor space.
400 gpm each
Bypass lines minimize thermal shock and maintain PZR/ RCS B-conc.
Bypass flow is set by adjusting the valves until PZR spray line temperature is stable between 495 – 505oF.
320oF DT limit between spray line temp and PZR Vapor Temp. 
Automatic:
Controlled from Master Pressure Controller
Start to open: 41% (2260psig)
Fully open:  72% (2310psig)
Manual Control is available

 
 
 
 
 
Term

Components, Purpose and Setpoints:

PORVS

Definition

PR1 and PR2

210,000 lbm/hr @ 2335 psig full open (always available even with POPs I/S, close 2315 psig
  • Limit system pressure to prevent high pressure reactor trip (2385 psig) and prevent undesirable safety valve operation by relieving at 2335 psig.
  • Opening setpoint lowered to 375 psig when POPS is armed to provide Brittle Fracture relief protection when RCS is  < 312oF
Channels II & IV – PR2 (Logic 2/2 to prevent inadvertent opening of PORV)
Channels I & III – PR1  (Logic 2/2 to prevent inadvertent opening of PORV)
Limits pressure to prevent high pressure trip for up to a 50% load rejection (auto rods and steam dumps) 
Each PORV has an associated Block Valve used for isolation in
case of leakage past the PORV
PR-6 powered from 230V MCC A
PR-7 powered from 230V MCC B
Block valves will auto open when POPs is i/s
 
 
Term

Components Purpose and Setpoints:

Safety Valves

Definition

Safety Valves (PR3, PR4 & PR5)

Max Flow is 420,000 lbm/hr each
Setpoint:  2485 psig
Designed to prevent RCS from exceeding 110% of design pressure limit (2735 psig)

Term

PZR Pressure Instrument Failures

CONTROLLING PT FAILS HIGH: 

Definition

RC PRESS DEVIATION HI Bezel Alarm

OHA D-8, RC PRESS HI
OHA E-42, PR1 1/2 TRIP
PZR Heaters Off
Sprays Full Open
Actual PZR Pressure Dropping
Rx Trip on Low PZR Press before 1865 psig (since Sprays still open) OR OT∆T if >70% RTP
SI at 1765 psig
OHA E-12, PZR PRESS LO
 
 
 
Term

PZR Pressure Instrument Failures

 

CONTROLLING PT FAILS LOW:
Definition

OHA D-16, RC PRESS LO

OHA E-28, PZR HTR ON PRESS LO
PZR Heaters all on
Actual PZR pressure Rising
Pressure will cycle 2315-2335 psig on PR2 only
Prevents AUTO opening of PR1. 
 
Term

PZR Pressure Instrument Failures:

 

ALARM CHANNEL PT FAILS HIGH:
Definition

RC PRESS  HI Bezel Alarm

OHA D-8, RC PRESS HI
OHA E-43, PR2 1/2 TRIP
 
Term

PZR Pressure Instrument Failure:

 

ALARM CHANNEL PT FAILS LOW:
 
Definition

OHA E-12, PZR PRESS LO

OHA D-16, RC PRESS LO
Interlock prevents AUTO opening of PR2 
 
Term
PZR Level Instrumentation Purpose:
Definition
  1. Provides a means of maintaining a constant mass during temperature changes, thus reducing the load on the Chemical and Volume Control system and the Waste Disposal system
  2. Controls charging pump or valves to maintain program level
  3. Provides protection for: PZR heaters and Isolation of Letdown
 
Term
PZR Level Instrumentation Design Basis:
Definition
  •  Liquid and vapor volumes are sufficient to provide smooth pressure response to programmed RCS volume change
  • Liquid volume is sufficient to prevent the heaters from being uncovered during a step load increase of 10 percent power
  • Steam volume is large enough to accommodate the surge resulting from a 50% reduction of load, utilizing automatic rod control and steam dump, without the water level reaching the high–level reactor trip setpoint (92%)
  • Sufficient steam volume to prevent water relief through the PZR Safety valves, in the event of a complete loss of load, assuming the increasing water level initiates a high PZR level reactor trip (92%) 
  • The PZR will not empty following a reactor trip, assuming a Reactor Trip causes a turbine trip
  • A safety injection signal will not be activated following a reactor trip, assuming a Reactor Trip causes a turbine trip 
Term
PZR level setpoints
Definition
  • 92% Lvl, Rx Trip >P7
  • 70% Hi Lvl Alarm
  • 57.8%, 100% Power Reference Lvl
  • 22.3%, 0% Power Reference Lvl
  • 17% Lo Lvl (causes LTDN Isoln Vlvs Close (CV2/277, Orafice vlvs CV3,4,5 close, PZR Htrs Off)
  • +5% Deviation BU Htrs Full On, and OHA E-20
  • -5% Deviation Bezel Alarm

 

Term
Scenarios and Indicated PZR Levels
Definition
  1. Containment Temp Increases- PZR Lvl Increases
  2. Reference Leg Leaks- PZR Lvl Increases
  3. DP Cell Failure- PZR Lvl Increases
  4. Variable Leg Loss (actual RCS Leak)- PZR Lvl Decreases

NOTE: If leak in vapor space-actual level will increase due to RCS voids

Term

PZR Level Instrument Failures:

 

CONTROLLING LT FAILS HIGH:
Definition

 

OHA E-20, PZR HTR ON LVL HI
Charging Flow Demand goes to Minimum
PZR Heaters come on (+5% Dev)
Actual PZR Level is Dropping, at 17%:
  • Orifice Isol Vlvs Close(CV3, 4, 5)
  • All PZR Heaters off
  • CV277 Closes
Actual Level now rises (min Chg, No L/D)
PZR LVL HI Bezel Alarm
OHA E-4, PZR LVL HI
Rx Trip at 92% (if > P-7)
 
Term

PZR Level Instrument Failure

 

CONTROLLING  LT FAILS LOW:
Definition

 

PZR LVL LO Bezel alarm
Chg Flow Demand Rises
Letdown Isolates (CV 2, 3, 4, 5)
All PZR Heaters Off
Actual level is Rising
OHA E-4, PZR LVL HI
Rx Trip at 92% (if > P-7)
 
Term

PZR Level Instrument Failures:

 

ALARM CHANNEL LT FAILS HIGH:
 
Definition

 

PZR LVL HI Bezel Alarm
OHA E-4, PZR LVL HI
 
Term

PZR Level Instrument Failures:

 

ALARM CHANNEL LT FAILS LOW:
 
Definition

 

Letdown Isolates (CV277, 3, 4, 5)
PZR Heaters Off
OHA E-36, PZR HTR OFF LVL LO
PZR Pressure Dropping (Htrs Off)
Actual PZR Level Rising (Min Chg, No L/D)
OHA E-4, PZR LVL HI
Rx Trip at 92% (if > P-7) ** Only Alarm Channel which will yield a Rx Trip**
Supporting users have an ad free experience!