NFM Board

• SM (Oversight)
• CRS (Command and Control)
• RM (Oversight and Direct Reactivity Manipulations)
• RO (Perform Manipulations)

• RE (Conrol Room Advisor)
• STA (Gives Engineering Advice to the Crew)

To prevent early criticality

• Start up channels (<2000cps)
• Log Channels - Safety channels A, B, C, D

1/m = CR0/CRx

• Phase 1: From reg group 1 @ 0 to PDIL
• Pull Doubbling
• Hold Points ~ 150 pcm

• Phase 2: From PDIL to -150 pcm
• Count Doubbling
• 1/2 distance to criticality

• Phase 3: from -150 to critical; trying to go to critical
• Pull 75-100 pcm
• SUR limit 1 DPM (target 0.3DPM)

Critical below the PDIL.

• PDIL is group 3 @ 60; do nt want to vilate the LAW!
• Since PDIL is the way we satisfy shutdown margin

The amount (pcm) by which the reactor can be made instantaneously subcritical assuming the most worthy rod is stuck full out. No credit is taken for partial strength.

If your counts double you have reached 1/2 the distance to criticality.

Count doubbling (pcm)

Estimated Critical Condition (based on prediction)

• Estimated Critical Boron Concentration (ECBC)
• Estimated Critical Rod Position (ECRP)

Determined from the rod worth curve

your overall doubbling must be <100 pcm.

the reactor will experience a continuous rise in power (counts) with no rod motion (which means the reactor is supercritical).

When two consecutive ACP's are below the PDIL or -500

• Power Dependent Insertion Limit
• Group 3 @ 60
• The LAW!

• Within  1 hour for < 96 hours
• Within 1 day for > 96 hours

• Fuel that causes fission at lower energies.
• U-235
• Pu-239
• Pu-241

The fractional change in neitron population per generation.

• Moderator Temperature Coefficient
• 
• Reactivity inserted into the core per degree of change in the mderator temperature

The MTC increases

• Negative; We want the reactor to be "inherently stable"
• 

• Xenon-135 and Samarium - 149
• They have extremely large microscopic cross sections that absorb thermal nuetrons

Xenon - a good poison

• 1. Directly from fission
• 2. Indirectly from radioactive decay of Iodine-15

• 1. From radiactive decay (beta minus)
• 2. From the neutron absorbing process (producing Xe-136) or burnout

Considered Xe free after 96 hours

Grappling a FFA initiates, ungrappling completes

• 1. Pre-planned: all details provided, changes require authorization
• 2. Field-directed: boundaries provided, details written in field

• 1. Availability: Shall
• 2. Eligibility: Shall
• 3. Security: Shall for recently discharged assemblies (n-1)
• 4. Strategic: optional
• *Always want to minimize fuel movement

the amount of reactivity beyond that required for criticality.

• 1. Control Rds (CEA's)
• 2. Soluble Poison (B-10)
• 3. Erbium part of fuel mix (Erbia pins)

• 1. Minimize control reacticity requirements at the BC
• 2. Able to use greater fuel load - allows fr a logner cycle
• 3. Limit "hot spots" when loaded in strategic locations.

• Local Power Density; power produced per foot of fuel rod
• Units of kW/ft.

Point of maximum heat transfer rate sustainable with nucleate boiling

1.34 (SAFDL)

• Decrease in Temperature
• Decrease in Pressure
• Decrease in Flow
• Decrease in Power Level

• critical heat flux/actual heat flux (can relate to the bioling water curve)
• Desireable to have a larger ratio; further away from nucleate boiling

DNB will result in fuel clad damage

• Reactor Core Safety limits (fuel Protection):
• 1. DNBR > 1.34; applies to MODES 1 & 2;
• 2. Fuel Peak Centerline Temperature <5080; applies to MODES 1 & 2
• RCS Pressure SL (RCS Integrity):
• 1. RCS Pressure <2750 psia; MODES 1-5

• Protects the fuel pellet
• PCT<5080F

• 1. Clad
• 2. RCS
• 3. Containment

• COLSS - Set point of 13.5 KW/ft. - Triggers alarm
• CPCS - Set point of 21 KW/ft - Triggers a Reactor Trip

• Core Operating Limit Supervisory System
• Assists operator in monitoring Tech Spec LCO's for DNBD and LHR for POL
• Uses Incores (61 strings, 5 levels per string spaced evenly)
• Not a safety system - will alarm but not trip the plant

• 1. Description of the Event
• 2. Licensing Bases
• 3. Analysis Methodology
• 4. NSSS Response to Event
• 5. Systems required to mitigate the event
• 6. Analysis History

SADBs are qualified documents that hekp engineers perform UFSAR ch. 15 Safety Analysis in accordance with the licensing bases.

PVAR --> Design Bases Change Package (DBCP) as according to 05DP-0NF22, Appendix B

Change mechs tab in SWMS

• A document for which the NRC has established requirements for content, reporting, and change control.
• Examples: UFSAR, Tech Specs, QA Plan, Security Plan, E-Plan, Fire Protection plan, COLR

No, they have never been submitted to the NRC for any type of approval.

an update of the safety analysis report submitted to the NRC to get an operating license

Yes, the NRC has established requirements for content, reporting, and change control

• 05DP-0NF22 - general design control requirements
• 04DP-0NF09 - more specific requirements for generating the analyses and SABDs

To determine whether prior NRC approval is needed prior to implementing a change.

Does not determine whether the activity is safe, it is the responsibility of the utility to determine safety.

Applicability Determination

Organized according to different events that have similiar effects.

• 1. Increase in heat removal by the secondary system
• 2. Decrease in heat removal by the secondary system
• 3. Decrease in reactor coolant flow rate
• 4. Reactivity and power distribution anomolies
• 5. Inrease in RCS inventories

• Moderate Frequent Events - May occur during a calendar year
• Infrequent Events - May occur during plant lifetime
• Limiting Fault Events - Low probability of occurance during a plant lifetime

Safety Analyses --> performed via AORs to demonstrate NRC requirements have been met --> Reviewed and approved by NRC --> become part of the UFSAR

SADBs were created to help NFM engineers understand how to perform Safety analyses according to licensing history.