ML12269A075

Attachment 5 - LaSalle County Station Engineering Change (EC) 389677, Revision 0, Evaluate UHS for 107 Degf Temperature

ML12269A075
Person / Time
Site:	LaSalle
Issue date:	09/17/2012
From:	Exelon Generation Co
To:	Office of Nuclear Reactor Regulation
References
RS-12-154
Download: ML12269A075 (3)

Text

ATTACHMENT 5 LaSalle County Station Engineering Change (EC) 389677, Revision 0, "Evaluate UHS for 107 DegF Temperature"

Engineering Change Print Date: 09/13/2012 EC Number 0000389677 000 Status/Date Facility CLOSED LAS 07/03/2012 Exetonv Type/Sub-type: EVAL STRU IIIIIIIIIIIIIII 1lIIIIIIIIIIIIIIIM IIIIIIIIIII 111lIIIIII lIIIIIIIIIII Page: 1 I.-.

EC

Title:

EVALUATE UHS FOR 107 DEGF TEMPERATURE Mod Nbr : KW1: SR KW2: KW3: KW4: KW5:

Master EC N Work Group : Temporary N Outage N Alert Group: DEM Aprd Reqd Date: 06/28/2012 WO Required Image Addr Exp Insvc Date:

Adv Wk Appvd: Alt Ref. Expires On Auto-Advance: Y Priority Auto-Asbuild N Caveat Outst: Department Discipline Resp Engr SEAN TANTON Location Milestone Date PassPort Name APPROVED 110-PREPARE EC 06/28/2012 TANTSX TANTON SEAN APPROVED 120-REVIEW EC 06/28/2012 ENGEGA ENGELS GREG I have performed a detailed, independent review.

My minor comments were editorial in nature and have been addressed satisfactorily. G. Engels 6/28/12.

APPROVED 300-APPROVE EC 06/28/2012 LSLLI SCHMIT DANIEL 800-ATTR CLOSED 07/03/2012 DRDWT TAYLOR WAYNE CLOSED Units Fac Unit Description LAS 00 COMMON UNIT Systems Fac System Description LAS ZZ SITE

EC 389677, Rev. 000 Evaluate the Ultimate Heat Sink (UHS) for 107 *F Temperature Reason for Evaluation/Scope:

Per Appendix B of the LaSalle UFSAR (Ref. 1), the UHS is designed in accordance with Reg. Guide 1.27, Rev. 1.

As such, the UHS is capable of providing sufficient cooling for at least 30 days based on the worst period of recorded weather conditions and to be capable of withstanding the following:

I) the most severe natural phenomena taken individually

2) the site-related events that historically have occurred or may occur

3) reasonably probable combinations of less severe natural phenomena and/or site-related events, and

4) a single failure of man-made structural features.

The purpose of this EC is to evaluate the UHS structure for a water temperature of 107 *F, which could occur during the design basis accident (DBA). The UHS analysis is contained within design analysis L-002457, Rev. 007 (Ref.

2). This EC will support a License Amendment Request to revise Technical Specification SR 3.7.3. 1, which specifies the temperature limit for the UHS.

Detailed Evaluation:

As documented in Reference I, the UHS is constructed of compacted clay materials. Several boring logs showing this are documented in Reference I. Clay materials can withstand temperatures well above 107 'F.

The structural integrity of the UHS is documented in Section 2.5.5 of Reference I. This evaluation is not dependent upon temperature. The slope stability of the UHS does not change with a change in UHS water temperature.

Additional failure analyses are documented in Subsection 2.5.5.2.5. The results of shad net failures concurrent with natural events such, seismic events, tornados, and other natural phenomena are documented. These are also not dependent upon UHS water temperature. The shad net has been constructed from materials (polyethylene net and steel mesh per Ref. 3) suitable for the conditions it will see.

Conclusions/Findings:

Based on the above, the UHS structure can withstand a water temperature of 107 *F. Reference 2 documents the temperature response of the UHS for the worst period of recorded weather conditions.

References:

I. LaSalle County Station UFSAR, Rev. 19

• Section 2.4, Hydrologic Engineering o 2.4.11, Low Water Considerations

• Section 2.5, Geology, Seismology, and Geotechnical Information o 2.5.4, Stability of Subsurface Materials and Foundations o 2.5.5, Stability of Slopes o 2.5.5.2.5, CSCS Pond Flume Failure Analysis o Figure 2.5-2 o Figure 2.5-19 o Figure 2.5-50 o Figure 2.5-59

• Section 3. 1, Conformance with NRC General Design Criteria o 3.1.2.4.15, Evaluation Against Criterion 44- Cooling Water

• Section 3.2, Classification of Structures, Components, and Systems

" Section 9.2, Water Systems o 9.2.6, Ultimate Heat Sink

• Appendix B, Conformance to Regulatory Guides o Regulatory Guide 1.27 - Rev. 1,Ultimate Heat Sink for Nuclear Power Plants

2. Design analysis L-002457, Rev. 007, LaSalle County Station Ultimate Heat Sink Analysis (See EC 389270)

3. Design analysis L-001417, Rev. 000, Hydraulic Evaluation of Shad Net Page I of I