ML18163A386
| ML18163A386 | |
| Person / Time | |
|---|---|
| Issue date: | 06/13/2018 |
| From: | NRC/NRR/DLP/PLPB |
| To: | |
| Golla J | |
| References | |
| Download: ML18163A386 (3) | |
Text
NRC ISG-06 Revision 2 Tabletop Material June 13-14, 2018 The examples provided from a Safety Function Summary Table, below, illustrate how the plant and I&C system safety analysis design basis information can be summarized to support vendor design, V&V, oversight, and regulatory review activities. The summary information serves to:
- facilitate interdisciplinary technical reviews by the licensee (e.g., safety analysis and I&C departments) to ensure plant safety analyses are correctly implemented in the I&C design,
- facilitate communication of key design basis information to the I&C vendor and support vendor oversight activities,
- support V&V activities to ensure key design basis requirements are correctly implemented, and
- facilitate regulatory reviews of the plant modification.
The example table also illustrates how the information can be presented to support the regulatory review of the modification. Four examples are presented show how change information can be presented for easy identification.
The first example presents a case where no changes are made to the BWR design basis as part of the plant I&C modernization modification. The new I&C equipment would simply implement the existing design-basis requirements on new equipment.
The second example illustrates a similar case where the design basis is based on engineering judgement rather than explicitly linked to a FSAR AOO or PA analysis.
The third example presents a case where limited changes are made to the design basis as part of the plant I&C modernization modification. Examples might be a change to an analytical limit or response time. The third example shown in the table illustrates a case where an architecture change was made to the ESFAS design to add a redundant 2-out-of-three-3 logic structure to the I&C system design. The change to the design basis information is shown in bold italics for easy identification. This change is similar to a change made for the Oconee design.
The fourth example presents a case where a new safety function is added to the design as part of a plant I&C modernization modification. The changes to the design basis information are shown in bold italics for easy identification. This change is similar to a change made for the Hope Creek Power Range Neutron Monitoring System design. The example only shows the new function added (item f) for brevity.
NRC ISG-06 Revision 2 Tabletop Material June 13-14, 2018 Examples from the Safety Function Summary Table for Section 4.2.1.1 Automated Protection Interlock/Permissive/
Condition for Nominal (100% RTP) Number of Channels Response Time Analytical Limit Actuation Logic Credited Interlock/Permissive/
Assumed in FSAR FSAR Event Variable(s) Function Override Trip/Actuation Event Analysis (AOO/PA) Signals Range Override Function (seconds)
EXAMPLE 1 Rod Nuclear Power 0 - 125% 100% 109% RTP 4 2oo4 Reactor Power 2oo4 Automatically 2 Withdrawal Overpower - Range RTP Trip Range switch to Accident, High Neutron Flux Linear bypass the Rod Setpoint Power Nuclear Ejection Permissive Overpower -
Accident, High Setpoint and the and enable Steam Line Nuclear Break Overpower -
Accident Low Setpoint EXAMPLE 2 None Nuclear Power 0 - 125% 100% 15% RTP 4 2oo4 Reactor Power 3oo4 Automatically None Overpower - Range RTP Trip Range enable Low Neutron Flux Linear Nuclear Setpoint Power Overpower -
Permissive High Setpoint and allow manual bypass of Nuclear Overpower -
Low Setpoint
NRC ISG-06 Revision 2 Tabletop Material June 13-14, 2018 Automated Protection Interlock/Permissive/
Condition for Nominal (100% RTP) Number of Channels Response Time Analytical Limit Actuation Logic Credited Interlock/Permissive/
Assumed in FSAR FSAR Event Variable(s) Function Override Trip/Actuation Event Analysis (AOO/PA) Signals Range Override Function (seconds)
EXAMPLE 3 Loss of RCS RCS 0 - 2500 2250 psi 1800 psi 3 Redundant ECCS RCS 2oo4 Allow manual 25 Coolant Pressure - Pressure psi 2oo3 Initiation Pressure bypass of Accident Low Permissive RCS Pressure Setpoint - Low Setpoint 3oo4 Automatically enable RCS Pressure -
Low Setpoint EXAMPLE 4 Anticipated Average LPRMs and 0 - 125% N/A See COLR 4 2oo4 Reactor OPRM 2oo4 Automatically 2 Thermal- Power Reactor RTP Trip Armed enable OPRM Hydraulic Range Recirculation Permissive Power Monitor Flow Oscillations f. OPRM Upscale Note: Changes associated with license amendment request shown in bold italics