Alarms

Alarms

Table of Contents

1. Unit Alarms
   1. TIMELY Alarms
      1. RCS Transient Conditions
   2. URGENT Alarms
   3. EMERGENCY Alarms
   4. CRITICAL Alarms
2. Alarm Panel
3. Alarm Sounder
   1. Tones
   2. Tone Assignments
   3. Preemption

Unit Alarms

TIMELY Alarms

Timely alarms should be looked at (they are alarms of course), but as their name implies are not as urgent as the others.

• Reactor Lost: In isolation this generally isn't a big deal (probably a timeout, or something got turned off), but it could be bad, so it's up to operator discretion. If the reactor was at high damage, then Containment Breach will be tripped as well, which is a CRITICAL alarm.
• Reactor High Temp: Reactor temperature at or exceeded 1150K.
• RPS Transient: An RPS trip has occurred that was not due to manual operator SCRAM or a timeout.
• RCS Transient: RCS transient conditions have been met (see below).

RCS Transient Conditions

An RCS transient is caused by any of the following per the Annunciator

• Reactor coolant level low
• Boiler water level low
• Turbine over speed
• Reactor coolant related RPS trip (coolant low, excess heated coolant)
• RCS flow low
• Max water return feed
• If "flow stability delay" has elapsed (15 seconds since last burn rate change), then
  • Boil rate mismatch
  • Coolant feed mismatch
  • Steam feed mismatch

URGENT Alarms

Urgent alarms demand operator attention, but are not immediate threats unless ignored.

• Reactor Over Temp: Reactor is over-temperature (≥1200K) and is now starting to take damage, but will not meltdown until ≥100% damage. A timer will be shown on the status to estimate how much time until 100% damage is reached.
• Reactor High Waste: Reactor waste has exceeded 85% full. At 100%, excess waste will vent and release significant amounts of radiation.

EMERGENCY Alarms

Emergency alarms represent a safety threat and may warrant evacuation after a facility SCRAM due to threat of a meltdown and/or radiation leaks.

• Reactor Damage: The reactor containment is taking damage, and a meltdown will occur at some point at or after 100% damage.
• Reactor Waste Leak: The reactor waste tank is full and radiation is now leaking.

CRITICAL Alarms

Remaining in the facility (if near the reactors) is very much not recommended at this point. Evacuation is encouraged.

• Containment Breach: The reactor melted down (guessed by reactor not being formed, not being connected, and having previously been >90% damage).
• Containment Radiation: Radiation has been detected at the unit radiation monitor (if configured).
• Critical Damage: The reactor has met or exceeded critical levels of damage and may meltdown at any point.

Alarm Panel

Tip

The alarm panel utilizes red vs green and yellow vs green indicators. If you have a colorblindness, please set that when configuring your device. Details on this can be found here. The ring-back status color (green) will be blue in any colorblind mode.

The orange button can be used to acknowledge (mute) individual alarms. The green button will Reset alarms in the "ring-back" state (alarm condition has been resolved). A green light indicates the alarm is in the ring-back state, meaning that the triggering conditions are no longer met, but the alarm had tripped since last reset. This allows the operator to know if something had happened that they missed.

The cyan tag next to the RPS transient indicates it is tied RPS data (which is in the cyan-bordered annunciator panel).

The blue tag next to RCS transient and turbine trip indicates those are tied to RCS data (which is in the blue-bordered annunciator panel).

• Containment Breach → red @ 4Hz light
• Containment Radiation → red @ 4Hz light
• Critical Damage → red @ 4Hz light
• Reactor Lost → red @ 4Hz light
• Reactor Damage → red @ 4Hz light
• Reactor Over Temp → red @ 4Hz light
• Reactor High Temp → yellow @ 2Hz light
• Reactor Waste Leak → red @ 4Hz light
• Reactor High Waste → yellow @ 2Hz light
• RPS Transient → yellow @ 2Hz light
• RCS High Waste → yellow @ 2Hz light
• Turbine Trip → red @ 4Hz light

Alarm Sounder

A speaker is used to play auditory alarms to accompany the alarm lights. For the sake of everyone's ears, alarms do not stack up. Multiple different sine waves start sounding really bad if you add them all together, so that is minimized by only playing alarms in combination that sound okay together.

Tones

• T_340Hz_Int_2Hz → 340Hz @ 2Hz Intermittent
• T_544Hz_440Hz_Alt → 544Hz 100ms / 440Hz 400ms Alternating
• T_660Hz_Int_125ms → 660Hz @ 125ms On 125ms Off
• T_745Hz_Int_1Hz → 745Hz @ 1Hz Intermittent
• T_800Hz_Int → 800Hz @ 0.25s On 1.75s Off
• T_800Hz_1000Hz_Alt → 800/1000Hz @ 0.25s Alternating
• T_1000Hz_Int → 1KHz 1s on, 1s off Intermittent
• T_1800Hz_Int_4Hz → 1.8KHz @ 4Hz Intermittent

Tone Assignments

• Containment Breach → 1.8KHz @ 4Hz Intermittent
• Containment Radiation → 800/1000Hz @ 0.25s Alternating
• Critical Damage → 660Hz @ 125ms On 125ms Off
• Reactor Lost → 340Hz @ 2Hz Intermittent
• Reactor Damage → 544Hz 100ms / 440Hz 400ms Alternating
• Reactor Over Temp → 544Hz 100ms / 440Hz 400ms Alternating
• Reactor High Temp → 800Hz @ 0.25s On 1.75s Off
• Reactor Waste Leak → 544Hz 100ms / 440Hz 400ms Alternating
• Reactor High Waste → 800Hz @ 0.25s On 1.75s Off
• RPS Transient → 1KHz 1s on, 1s off Intermittent
• RCS High Waste → 800Hz @ 0.25s On 1.75s Off
• Turbine Trip → 745Hz @ 1Hz Intermittent

Preemption

A concept of preemption is used to avoid playing too many alarms at once. In addition to that distorting the audio, certain alarms in combination are very uncomfortable to listen to, beyond what one usually would expect from an alarm. Preemption here ensures higher priority tones are always played and conflicting tones are disabled.

• Containment Breach takes priority and will play instead of any other alarms.
• Otherwise:
  • Critical Damage
  • RPS Transient (which will disable T_340Hz_Int_2Hz)
  • If not critical damage:
    1. Reactor Damage or Reactor Over Temp or Reactor Waste Leak
    2. Turbine Trip
    3. Reactor Lost
    4. Reactor High Temp or Reactor High Waste or RCS Transient

Containment Radiation will always play in synchrony with any other alarms, including Containment Breach. In order to avoid painful audio combinations it will:

• Disable RPS Transient alarm if active due to conflict
• Re-enable Reactor Lost alarm due to no longer conflicting with RPS Transient (if alarm is active)
• Also disable T_745Hz_Int_1Hz, T_800Hz_Int, T_1000Hz_Int