ML060590027

Technical Specifications, Eliminate Power Range Neutron High-Flux Negative Rate Reactor Trip Function. Enclosure 2

ML060590027
Person / Time
Site:	Farley
Issue date:	02/27/2006
From:	Martin R Plant Licensing Branch III-2
To:	Stinson L Southern Nuclear Operating Co
Martin R, NRR/DORL, 415-1493
Shared Package
ML053200004	List: ML053190381 ML060590027
References
TAC MC8524
Download: ML060590027 (3)

Text

RTS Instrumentation 3.3.1 Table 3.3.1-1 (page 1of 8)

Reactor Trip System Inshumentation APPLICABLE MODES OR OTHER SPECIFIED REQUIRED SURVEILLANCE ALLOWABLE TRIP FUNCTION CONDITIONS CHANNELS CONDITIONS REQUIREMENTS VALUE SETPOINT

1. Manual Reactor 1.2 2 B SR 3.3.1.12 14A NA Trip 3 (a),4(a), 5 (a) 2 C SR 3.3.1.12 WA NA

2. Power Range Neutron Flux

a. High 1,2 4 D SR 3.3.1.1 5 109.4% RTP S5109%

SR 3.3.12 RTP SR 3.3.1.7 SR 3.3.1.10 SR 3.3.1.14

b. Low 1 (b),2 4 E SR 3.3.1.1 5 25.4% RTP 5 25% RTP SR 3.3.1.8 SR 3.3.1.10 SR 3.3.1-14

3. Power Range Neutron Flux Rate

a. High Positive 1,2 4 D SR 3.3.1.7 5 5.4% RTP 5 5%RTP Rate SR 3.3.1.10 with time with time corstant constant

Ž2 sec 2 2 sec

b. [Unit I only) 1,2 4 D SR 3.3.1.7 S 5.4% RTP 5 5% RTP I High Negative SR 3.3.1.10 with time with time Rate corstant constant i2 sec Ž2 sec

4. Intermediate 1 (b), 2 (c) 2 F,G SR 3.3.1.1 S 40'YO RTP 5 35% RTP Range Neutron SR 3.3.1.8 Flux SR 3.3.1.10 2 (d) 2 H SR 3.3.1.1 s 40%K RTP 5 35% RTP SR 3.3.1.8 SR 3.3.1.10 (a) With Reactor Trip Breakers (RTBs) closed and Rod Control System capable cffad wnthdrawal.

(b) Below the P-10 (Power Range Neutron Flux) interlocks.

(c) Above the P-6 (Intermediate Range Neutron Flux) Interlocks.

(d) Below the P-6 (Intermediate Range Neutron Flux) interlocks.

Farley Units 1 and 2 3.3.1-14 Amendment No. 146 (Unit 1)

Amendment No. 164 (Unit 2)

RTS Instrumentation B 3.3.1 BASES APPLICABLE a. Power Range Neutron Flux-High Positive Rate (continued)

SAFETY ANALYSES, LCO, and Power Range Neutron Flux -High and Low Setpoint trip APPLICABILITY Functions to ensure that the criteria are met for a rod ejection event.

The LCO requires all four of the Power Range Neutron Flux -

High Positive Rate channels to be OPERABLE. The channels are combined in a 2-out-of-4 trip Logic.

In MODE 1 or 2, when there is a potential to add a large amount of positive reactivity from a rod ejection accident (REA),

the Power Range Neutron Flux- High Positive Rate trip must be OPERABLE. In MODE 3, 4, 5, or 6, the Power Range Neutron Flux-High Positive Rate trip Function does not have to be OPERABLE because other RTS trip Functions and administrative controls will provide protection against positive reactivity additions. Also, since only the shutdown banks may be withdrawn in MODE 3, 4, or 5, the remaining complement of control bank worth ensures a sufficient degree of SDM in the event of an REA. In MODE 6, no rods are withdrawn and the SDM is increased during refueling operations. The reactor vessel head is also removed or the closure bolts are detensioned preventing any pressure buildup.

b. IUnit 1 orily] Power Range Neutron Flux-High Negative Rate The Power Range Neutron Flux -High Negative Rate trip Function ensures that protection is provided for multiple rod drop accidents.

The LCO requires all four Power Range Neutron Flux-High Negative Rate channels to be OPERABLE. The channels are combined in a 2-out-of-4 trip Logic.

(continued)

Farley Units 1 and 2 B 3.3.1-1 1 Revision

RTS Instrumentation B 3.3.1 BASES APPLICABLE b. rUnit 1 orilvi Power Ranae Neutron Flux-High Negative Rate SAFETY ANALYSES, (continued)

LCO, and APPLICABILITY In MODE 1 or 2, when there is potential for a multiple rod drop accident to occur, the Power Range Neutron Flux -High Negative Rate trip must be OPERABLE. In MODE 3, 4, 5, or 6, the Poweir Range Neutron Flux-High Negative Rate trip Function does not have to be OPERABLE because the core is not critical and DNB is not a concern.

4. Intermediate Range Neutron Flux The Intermediate Range Neutron Flux trip Function ensures that protection is provided against an uncontrolled RCCA bank rod withdrawal accident from a subcritical condition during startup. This trip Function provides diverse protection to the Power Range Neutron Flux--Low Setpoint trip Function. The NIS intermediate range detectors are located external to the reactor vessel and measure neutrons leaking from the core. The NIS intermediate range channels also provide a control interlock signal to prevent automatic and manual rod withdrawal prior to initiating a reactor trip.

Limiting further rod withdrawal may terminate the transient and eliminate the need to trip the reactor. No credit is taken in the safety analyses for this trip function.

The LCO requires two channels of Intermediate Range Neutron Flux to be OPERABLE. Two OPERABLE channels are sLfficient to ensure no single random failure will disable this trip Function. The trip function is accomplished by a 1-out-of-2 trip Logic.

Because this trip Function is important only during startup, there is generally no need to disable channels for on-line testing while the Function is required to be OPERABLE. Therefore, a third channel is unnecessary.

In MODE 1 below the P-10 setpoint, and in MODE 2, when there is a potential for an uncontrolled RCCA bank rod withdrawal accident during reactor startup, the Intermediate Range Neutron Flux trip must be OPERABLE. Above the P-10 setpoint, the Power Range Neutron Flux-- High Setpoint trip and the Power Range Neutron Flux -High Positive Rate trip provide core protection for a rod (continued)

Farley Units 1 and 2 13 3.3.1-12 Revision