ML22332A451

Attachment 3 - Markup of Technical Specification Bases Pages (for Information Only)

ML22332A451
Person / Time
Site:	LaSalle
Issue date:	11/10/2022
From:	Constellation Energy Generation
To:	Office of Nuclear Reactor Regulation
Shared Package
ML22332A448	List: ML22332A449 ML22332A450 ML22332A451 ML22332A453 ML22332A454 ML22332A455 ML22332A456 ML22332A457 RS-22-091, Attachment 4 - Transware Enterprises Inc. Affidavits
References
RS-22-091
Download: ML22332A451 (1)

Text

ATTACHMENT 3

Markup of Technical Specification Bases Pages (for information only)

RCS P/T Limits B 3.4.11

B 3.4 REACTOR COOLANT SYSTEM (RCS)

B 3.4.11 RCS Pressure and Temperature (P/T) Limits

BASES

BACKGROUND All components of the RCS are designed to withstand effects of cyclic loads due to system pressure and temperature changes. These loads are introduced by startup (heatup) and shutdown (cooldown) operations, power transients, and reactor trips. This LCO limits the pressure and temperature changes during RCS heatup and cooldown, within the design assumptions and the stress limits for cyclic operation.

The Specification contains P/T limit curves for heatup, cooldown, inservice leak and hydrostatic testing, and criticality and also limits the maximum rate of change of reactor coolant temperature. The P/T limit curves are applicable for 32 effective full power years.

Each P/T limit curve defines an acceptable region for normal operation. The usual use of the curves is operational guidance during heatup or cooldown maneuvering, when pressure and temperature indications are monitored and compared to the applicable curve to determine that operation is within the allowable region.

The LCO establishes operating limits that provide a margin to brittle failure of the reactor vessel and piping of the reactor coolant pressure boundary (RCPB). The vessel is the component most subject to brittle failure. Therefore, the LCO limits apply mainly to the vessel.

10 CFR 50, Appendix G (Ref. 1), requires the establishment of P/T limits for material fracture toughness requirements of the RCPB materials. Reference 1 requires an adequate margin to brittle failure during normal operation, anticipated operational occurrences, and system hydrostatic tests. It mandates the use of the American Society of Mechanical Engineers (ASME) Code,Section III, Appendix G (Ref. 2).

The actual shift in the RTNDT of the vessel material will be established periodically by removing and evaluating the irradiated reactor vessel material specimens, in accordance with ASTM E 185 (Ref. 3) and 10 CFR 50, Appendix H (continued)

LaSalle 1 and 2 B 3.4.11-1 Revision 50 RCS P/T Limits B 3.4.11

BASES

APPLICABLE P/T limits are not derived from any DBA, there are no SAFETY ANALYSES acceptance limits related to the P/T limits. Rather, the (continued) P/T limits are acceptance limits themselves since they preclude operation in an unanalyzed condition.

RCS P/T limits satisfy Criterion 2 of 10 CFR 50.36(c)(2)(ii).

LCO The elements of this LCO are:

a. RCS pressure and temperature are within the limits specified in Figures 3.4.11-1, 3.4.11-2, 3.4.11-3, 3.4.11-4, 3.4.11-5, and 3.4.11-6, heatup and cooldown rates are 100F in any 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> period during RCS heatup, cooldown, and inservice leak and hydrostatic testing, and the RCS temperature change during system leakage and hydrostatic testing is 20F in any 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> period when the RCS temperature and pressure are not within the limits of Figure 3.4.11-2 and 3.4.11-5 as applicable;

b. The temperature difference between the reactor vessel bottom head coolant and the reactor pressure vessel (RPV) coolant is 145F during recirculation pump startup in MODES 1, 2, 3, and 4;

c. The temperature difference between the reactor coolant in the respective recirculation loop and in the reactor vessel is 50F during recirculation pump startup in MODES 1, 2, 3, and 4;

d. RCS pressure and temperature are within the applicable criticality limits specified in Figures 3.4.11-3 and 3.4.11-6, prior to achieving criticality; and

e. The reactor vessel flange and the head flange temperatures are 72F for Unit 1 and 86F for Unit 2 when tensioning the reactor vessel head bolting studs and when the reactor head is tensioned.

These limits define allowable operating regions and permit a large number of operating cycles while also providing a wide margin to nonductile failure.

(continued)

LaSalle 1 and 2 B 3.4.11-3 Revision 13 RCS P/T Limits B 3.4.11

BASES

SURVEILLANCE SR 3.4.11.1 (continued)

REQUIREMENTS The limits of Figures 3.4.11-1, 3.4.11-2, 3.4.11-3, 3.4.11-4, 3.4.11-5, and 3.4.11-6 are met when operation is to the right of the applicable curve.

Surveillance for heatup, cooldown, or inservice leak and hydrostatic testing may be discontinued when the criteria given in the relevant plant procedure for ending the activity are satisfied.

This SR has been modified by a Note that requires this Surveillance to be performed only during system heatup and cooldown operations and inservice leak and hydrostatic testing.

SR 3.4.11.2

A separate limit is used when the reactor is approaching criticality. Consequently, the RCS pressure and temperature must be verified within the appropriate limits before withdrawing control rods that will make the reactor critical. The limits of Figures 3.4.11-3 and 3.4.11-6 are met when operation is to the right of the applicable curve.

Performing the Surveillance within 15 minutes before control rod withdrawal for the purpose of achieving criticality provides adequate assurance that the limits will not be exceeded between the time of the Surveillance and the time of the control rod withdrawal.

SR 3.4.11.3 and SR 3.4.11.4

Differential temperatures within the applicable limits ensure that thermal stresses resulting from the startup of an idle recirculation pump will not exceed design allowances. In addition, compliance with these limits ensures that the assumptions of the analysis for the startup of an idle recirculation loop (Ref. 8) are satisfied.

(continued)

LaSalle 1 and 2 B 3.4.11-7 Revision 51