ML110050079

Technical Specifications and Tech Spec Bases Manual Holders

ML110050079
Person / Time
Site:	Mcguire, McGuire
Issue date:	12/28/2010
From:	Beaver B Duke Energy Carolinas
To:	Office of Nuclear Reactor Regulation
References
DUK103620020
Download: ML110050079 (5)

Text

DISPOSITION OF THE ORIGINAL DOCUMENT WILL BE TO 1w Iw Normal THE TRANSMITTAL SIGNATURE UNLESS RECIPIENT IS Date: 12128/10 PRIORITY OTHERWISE IDENTIFIED BELOW Document Transmittal #: DUK103620020

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• DATE DISTR CODE 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 TOTAL MEMO NA - 12/14/10 MADM-04B vi V1 V1 V1 x V1 Vi V3 V1 V1 V1 V2 V1 V1 V1 35 TSB 2.1.2 NA 109 12/14/10

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R IT___REPKO I ___ .I* -~--~ ___ - ___ -~___ _______

REMARKS: PLEASE UPDATE ACCORDINGLY REMARKS: ACCORDINGLY R T REPKO VICE PRESIDENT MCGUIRE NUCLEAR STATION BY:

BONNIE C BEAVER MGO1RC BCB/TLC

December 14, 2010 MEMORANDUM To: All McGuire Nuclear Station Technical Specification (TS) and Tech Spec Bases (TSB) Manual Holders

Subject:

McGuire TS and TSB Updates REMOVE INSERT TS Bases Manual TSB 2.1.2 (entire document) TSB 2.1.2 (Rev 109)

Bases 2.1.2 was inadvertently left out of the original package containing Bases Revision 109. Please file per instruction above.

Revision numbers may skip numbers due to Regulatory Compliance Filing System.

Please call me if you have questions.

Bonnie Beaver Regulatory Compliance 875-4180

RCS Pressure SL B 2.1.2 B 2.0 SAFETY LIMITS (SLs)

B 2.1.2 Reactor Coolant System (RCS) Pressure SL BASES BACKGROUND The SL on RCS pressure protects the integrity of the RCS against overpressurization. In the event of fuel cladding failure, fission products are released into the reactor coolant. The RCS then serves as the primary barrier in preventing the release of fission products into the atmosphere. By establishing an upper limit on RCS pressure, the continued integrity of the RCS is ensured. According to 10 CFR 50, Appendix A, GDC 14, "Reactor Coolant Pressure Boundary," and GDC 15, "Reactor Coolant System Design" (Ref. 1), the reactor coolant pressure boundary (RCPB) design conditions are not to be exceeded during normal operation and anticipated operational occurrences (AOOs).

Also, in accordance with GDC 28, "Reactivity Limits" (Ref. 1), reactivity accidents, including rod ejection, do not result in damage to the RCPB greater than limited local yielding.

The design pressure of the RCS is 2500 psia. During normal operation and AOOs, RCS pressure is limited from exceeding the design pressure by more than 10%, in accordance with Section III of the ASME Code (Ref. 2). To ensure system integrity, all RCS components are hydrostatically tested at 125% of design pressure, according to the ASME Code requirements prior to initial operation when there is no fuel in the core. Following inception of unit operation, RCS components shall be pressure tested, in accordance with the requirements of the ASME OM Code (Ref. 3).

Overpressurization of the RCS could result in a breach of the RCPB. If such a breach occurs in conjunction with a fuel cladding failure, fission productscould enter the containment atmosphere, raising concerns relative to limits on radioactive releases specified in 10 CFR 50.67, "Accident Source Term" (Ref. 4).

APPLICABLE The RCS pressurizer safety valves, the main steam safety valves SAFETY ANALYSES (MSSVs), and the reactor high pressure trip have settings established to ensure that the RCS pressure SL will not be exceeded.

The.RCS pressurizer safety valves are sized to prevent system pressure from exceeding the design pressure by more than 10%, as specified in Section III of the ASME Code for Nuclear Power Plant Components McGuire Units 1 and 2 B 21.2-1 Revision No. 109

RCS Pressure SL B 2.1.2 BASES 'I APPLICABLE SAFETY ANALYSES (continued)

(Ref. 2), for anticipated operational occurrences. During the transient, no control actions are assumed, except that the safety valves on the secondary plant are assumed to open when the steam pressure reaches the secondary plant safety valve settings, and nominal feedwater supply is maintained.

The Reactor Trip System setpoints (Ref. 5), together with the settings of the MSSVs, provide pressure protection for normal operation and AOOs.

The reactor high pressure trip setpoint is specifically set to provide protection against overpressurization (Ref. 5). The safety analyses for both the high pressure trip and the RCS pressurizer safety valves are performed using conservative assumptions relative to pressure control devices.

More specifically, no credit is taken for operation of the following:

a. Pressurizer power operated relief valves (PORVs);

b. Steam Generator (SG) PORVs;

c. Steam Dump System;

d. Rod Control System; e.' Pressurizer Level Control System; or

f. Pressurizer spray valves.

SAFETY LIMITS The maximum transient pressure allowed in the RCS pressure vessel under the ASME Code,Section III, is 110% of design pressure. The maximum transient pressure allowed in the RCS piping, valves, and fittings under ASME Code Section III (Ref. 2) is 120% of design pressure.

The most limiting of these two allowances is the 110% of design pressure; therefore, the SL on maximum allowable RCS pressure is 2735 psig.

APPLICABILITY SL 2.1.2 applies in MODES 1, 2, 3, 4, and 5 because this SL could be approached or exceeded in these MODES due to overpressurization events. The SL is not applicable in MODE 6 because the reactor vessel head closure bolts are not fully tightened, making it unlikely that the RCS can be pressurized.

McGuire Units 1 and 2 B 2.1.2-2 Revision No.. 109

I RCS Pressure SL B 2.1.2 BASES SAFETY LIMIT If the RCS pressure SL is violated when the reactor is in MODE 1 or 2, VIOLATIONS the requirement is to restore compliance and be in MODE 3 within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />.

Exceeding the RCS pressure SL may cause immediate RCS failure and create a potential for radioactive releases in excess of 10 CFR 50.67, "Accident Source Term," limits (Ref. 4).

The allowable Completion Time of 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> recognizes the importance of reducing power level to a MODE of operation where the potential for challenges to safety systems is minimized.

If the RCS pressure SL is exceeded in MODE 3, 4, or 5, RCS pressure must be restored to within the SL value within 5 minutes. Exceeding the RCS pressure SL in MODE 3, 4, or 5 is more severe than exceeding this SL in MODE 1 or 2, since the reactor vessel temperature may be lower and the vessel material, consequently, less ductile. As such, pressure must be reduced to less than the SL within 5 minutes. The action does not require reducing MODES, since this would require reducing temperature, which would compound the problem by adding thermal gradient stresses to the existing pressure stress.

REFERENCES 1.. 10 CFR 50, Appendix A, GDC 14, GDC 15, and GDC 28.

2. ASME, Boiler and Pressure Vessel Code,Section III, 1971 Edition, Winter 1971 Addenda.

3. ASME Code for Operation and Maintenance of Nuclear Power Plants.

4. 10 CFR 50.67, "Accident Source Term."

5. UFSAR, Section 7.2.

McGuire Units 1 and 2 B 2.1.2-3 Revision No. 109