ML041340511

Corrective Action Program No. 020538 - Enclosure 2

ML041340511
Person / Time
Site:	Kewaunee
Issue date:	03/23/2004
From:	Nuclear Management Co
To:	Office of Nuclear Reactor Regulation
References
WCAP-10325
Download: ML041340511 (4)

Text

Nuclear Management Company Page I of 4

}J State Change History Initiate AR Pre-Screen Submit to Screening Team AR Screening Que 0 3/23/2004 4:33:10 PM 0 3/23/2004 4:48:40 PM by RISTE, GERALD _. Owner (None) by SMITH, TIMOTHY Owner KNPP CAP Admin

!3 Section 1 Activity Request Id: CAP020538 Activity Type: CAP Submit Date: 3/23/2004 4:33:10 PM i One Line

Description:

Applicability of WCAP-10325 to KNPP t Detailed

Description:

3/23/2004 4:33:10 PM - RISTE, GERALD:

During a review of the licensing basis for replacement of the steam generators at Prairie Island a question arose concerning the applicability of WCAP-10325 to Westinghouse 2 LOOP PWRs with upper plenum injection (UPI). WCAP 10325-P-A is a Westinghouse methodology for determining the mass and energy release into the containment structure following a large break loss-of-coolant accident (LBLOCA). Westinghouse states that the current licensed methodology in WCAP-1 0325-P-A for mass and energy releases for containment integrity does not model the specific flow split and alignment of UPI. The question raised is the acceptability of the use of WCAP-1 0325 at KNPP and did the NRC know that KNPP was an upper plenum injection plant.

This CAP is written to document the review of this issue.

Initiator: RISTE, GERALD CD Initiator Department: LK Licensing KE Z Date/Time of Discovery: 3/23/2004 4:25:38 PM Date/Time of Occurrence: 3/23/2004 4:25:38 PM Identified By: Site-identified System: (None)

Equipment # (1st): (None) Equipment Type (1st): (None)

Equipment # (2nd): (None) Equipment Type (2nd): (None)

Equipment # (3rd): (None) Equipment Type (3rd): (None)

Site/Unit: Kewaunee Why did this occur?: 3/23/2004 4:33:10 PM - RISTE, GERALD:

NMC is replacing the steam generators at Prairie Island. One of the engineers on the project was reviewing this WCAP and questioned the applicability to UPI plants Immediate Action Taken: 3/23/2004 4:33:10 PM - RISTE, GERALD:

Reviewed licensing basis, discussed with Westinghouse, Uprate personnel, and SGR personnel. See attached evaluation.

Recommendations: 3/23/2004 4:33:10 PM - RISTE, GERALD:

Close to actions taken i Notify Me During Eval?: N v SRO Review Required?: N 1l Section 2 Operability Status: NA v Compensatory Actions: N Basis for Operability: 3/23/2004 4:48:40 PM - SMITH, TIMOTHY:

CAP written to document response to questions raised by other NMC site. Evaluation addresses questions and acceptability of current design basis. No non-conforming condition identified. No affect on plant equipment, operation or security.

0 Unplanned TSAC Entry: N

• External Notification: N E3 Section 3 Screened?: N  : Significance Level: D INPO OE Reqd?: N Potential MRFF?: N C QA/Nuclear Oversight?: N v Licensing Review?: N Good Catch/Well Doc'd?: NA a Section 4 ENCLOSURE 2 httn- //Pnwvir9/tImtrqrk/tmtrnrek d19?T.RIwPn fre,&Temnlate=viewhndv&recordi d=589 138&ta... 3/25/2004

Nuclear Management Company Page 2 of 4 Inappropriate Action:

Process: (None) Activity: (None)

Human Error Type: (None) Human Perf Fail Mode: (None)

Equip Failure Mode: (None) Process Fail Mode: (None)

Org/Mgt Failure Mode: (None) i&Group Causing Prob: (None)

Hot Buttons: (None)

E Section 5 CAP Admin: KNPP CAP Admin 3 Prescreener: (None)

@Project: Corrective Action Process (CAP) 0 State: AR Screening Que i Active/inactive: Active i Submitter: RISTE, GERALD 0 Owner: KNPP CAP Admin Last Modified Date: 3/24/2004 3:37:01 PM i Last Modifier: HOLLY, JOHN

• Last State Change Date: 3/2312004 4:48:40 PM

- Last State Changer: SMITH, TIMOTHY D Close Date:

NUTRK ID:

1. of Children: 0

References:

Update:

Prescreen Comments: 3/24/2004 3:23:48 PM - VANVALKENBURG, TERRY:

Close to Actions Taken Import Memo Field:

OPR Completed?: N OLDACTIONNUM:

sub-tsid: 0 original-projectjid: 0 original-issueid:

Site: Kewaunee Cartridge and Frame:

El Notes/Comments Technical Evaluation of Applicablity of WCAP 10325 Methodology by HOLLY, JOHN (3/24/2004 3:36:38 PM)

WCAP 10325-P-A LOCA mass and energy release methods (see reference 1) are applicable and conservative for modeling the KNPP LOCA mass and energy release for containment analysis based on the following technical rationale. This technical argument has also been documented in a Westinghouse position paper (see reference 2).

1)The KNPP LOCA mass and energy release methodology, WCAP 10325 -P-A methodology, models a conservative release of all RCS and reactor core stored energy into the containment. This conservative modeling of the RCS and reactor core stored energy maximizes the containment pressure and temperature response to a LOCA.

2) Detailed core and upper plenum modeling, important to the LOCA core fuel heat up analysis, is not as significant for containment analysis. Upper Plenum Injection (UPI) is modeled for the KNPP LOCA core response analysis. It is conservative to not model or credit UPI for LOCA mass and energy release analysis.

3) Cross flow communication in the KNPP core open fuel lattice results in similar core flooding behavior between upper plenum injection (UPI) and cold leg injection (CLI). The KNPP core in both safety injection (SI) alignments is essentially flooded from the bottom up.

4) There is a greater amount of steam condensation with upper plenum injection (UPI) than with cold leg injection (CLI).

Greater steam condensation reduces the mass and energy release and the containment pressure and temperature response. The higher steam condensation with UPI was confirmed by the Upper Plenum Test Facility (UPTF) experiments (see reference 3).

5) WCAP 10325-P-A methodology models a 95%/5% flow split where 95% of the flow off of the top of the core goes to the RCS break and 5% of the flow passes through the intact RCS loop and is mixed with CLI. A UPI model would have a more efficient mixing of steam exiting the core with the UPI fluid at the upper core plate. More efficient mixing of steam exiting the core reduces the mass and energy release and the containment pressure and temperature response. In the WCAP 10325-P-A methodology only steam that exits thru the intact RCS loop piping (5% of the flow) near the CLI point is condensed.

6) The RCS water flow through the steam generators (SG's) that removes energy from the SG secondary side that can then httn://enws02/tmtrackltmtrack.dll ?IssuePare&Temnlate=viewbodv&recordid=58913 8&ta... 3/25/2004

Nuclear Management Company Paue 3 of 4 be released to containment, is high based on the WCAP 10325-P-A methods. The RCS mass flow thru the SG's was shown to be limited in the UPTF experiments due to de-entrainment of RCS fluid in the SG inlet plenum. This de-entrainment limits the water that passes through the steam generators, limiting the energy transferred from the steam generator secondary to the break water then out the break into containment.

Based on the above technical rationale the LOCA mass and energy release methodology in WCAP 10325-P-A is conservative for use in containment analysis for KNPP with UPI. Note this conclusion is consistent with the conclusion by Westinghouse documented in reference 2.

From a licensing perspective the WCAP 10325- P- A methodology is acceptable for use at KNPP since:

1) WCAP 10325-P-A methods were approved for use for the KNPP SGR safety analyses. They are documented in the DCR 2858 Mod. 1 Safety Review / Safety Evaluation.

2) WCAP 10325-P-A methods are consistent with the original KNPP licensing basis methods, which also did not model the UPI safety injection alignment for LOCA mass and energy release analyses.

3) WCAP 10325-P-A methods are the current KNPP licensing basis analysis methods and are documented in KNPP USAR section 14.3.4.

4) WCAP 10325-P-A methods are documented and approved in the stretch power uprate license amendment NRC safety evaluation dated 2-27-04. The LOCA mass and energy release methods were presented in section 6.4.1 of reference 4.

References:

1) WCAP 10325-P-A Westinghouse LOCA Mass and Energy Release Model for Containment Design" March 1979 Version.

2) Letter KEW-UPRATE-04-085 dated 3-24-04 from Roy Owoc (Westinghouse) to Harv Hanneman (NMC) submitting "Applicability of WCAP 10325 to Westinghouse PWR UPI Plants"

3) Summary of Results from the UPTF Upper Plenum Injection (UPI) Separate Effects Test, Comparison to Previous Scaled Test, and Application to U.S. Pressurized Water Reactors," MPR Associates, Inc., jointly prepared by Siemens Corp (UB KWU) Erlangen, FRG and MPR Associates Washington, D.C., December 1988.

4) License Amendment Request 195 attachment 4, submitted by KNPP to NRC May 22, 2003.

Technical Evaluation of Applicablity of WCAP 10325 Methodology by HOLLY, JOHN (3/24/2004 3:37:01 PM) ,

WCAP 10325-P-A LOCA mass and energy release methods (see reference 1) are applicable and conservative for modeling the KNPP LOCA mass and energy release for containment analysis based on the following technical rationale. This technical argument has also been documented in a Westinghouse position paper (see reference 2).

1) The KNPP LOCA mass and energy release methodology, WCAP 10325 -P-A methodology, models a conservative release of all RCS and reactor core stored energy into the containment. This conservative modeling of the RCS and reactor core stored energy maximizes the containment pressure and temperature response to a LOCA.

2) Detailed core and upper plenum modeling, important to the LOCA core fuel heat up analysis, is not as significant for containment analysis. Upper Plenum Injection (UPI) is modeled for the KNPP LOCA core response analysis. It is conservative to not model or credit UPI for LOCA mass and energy release analysis.

3) Cross flow communication in the KNPP core open fuel lattice results in similar core flooding behavior between upper plenum injection (UPI) and cold leg injection (CLI). The KNPP core in both safety injection (SI) alignments is essentially flooded from the bottom up.

4) There is a greater amount of steam condensation with upper plenum injection (UPI) than with cold leg injection (CLI).

Greater steam condensation reduces the mass and energy release and the containment pressure and temperature response. The higher steam condensation with UPI was confirmed by the Upper Plenum Test Facility (UPTF) experiments (see reference 3).

5) WCAP 10325-P-A methodology models a 95%/5% flow split where 95% of the flow off of the top of the core goes to the RCS break and 5% of the flow passes through the intact RCS loop and is mixed with CLI. A UPI model would have a more efficient mixing of steam exiting the core with the UPI fluid at the upper core plate. More efficient mixing of steam exiting the core reduces the mass and energy release and the containment pressure and temperature response. In the WCAP 10325-P-A methodology only steam that exits thru the intact RCS loop piping (5%of the flow) near the CLI point is condensed.

6) The RCS water flow through the steam generators (SG's) that removes energy from the SG secondary side that can then be released to containment, is high based on the WCAP 10325-P-A methods. The RCS mass flow thru the SG's was shown to be limited in the UPTF experiments due to de-entrainment of RCS fluid in the SG inlet plenum. This de-entrainment limits the water that passes through the steam generators, limiting the energy transferred from the steam generator secondary to the break water then out the break into containment.

Based on the above technical rationale the LOCA mass and energy release methodology in WCAP 10325-P-A is conservative for use in containment analysis for KNPP with UPI. Note this conclusion is consistent with the conclusion by Westinghouse documented in reference 2.

httn-//nwsO2/tmtrack/tmtrack.dll?IssuePare&Template=viewbodv&recordi d=5 8913 8&ta ... 3/25/2004

Nuclear Management Company Page 4 of 4 From a licensing perspective the WCAP 10325- P- A methodology is acceptable for use at KNPP since:

1) WCAP 10325-P-A methods were approved for use for the KNPP SGR safety analyses. They are documented in the DCR 2858 Mod. 1 Safety Review / Safety Evaluation.

2) WCAP 10325-P-A methods are consistent with the original KNPP licensing basis methods, which also did not model the UPI safety injection alignment for LOCA mass and energy release analyses.

3) WCAP 10325-P-A methods are the current KNPP licensing basis analysis methods and are documented in KNPP USAR section 14.3.4.

4) WCAP 10325-P-A methods are documented and approved in the stretch power uprate license amendment NRC safety evaluation dated 2-27-04. The LOCA mass and energy release methods were presented in section 6.4.1 of reference 4.

References:

1) WCAP 10325-P-A 'Westinghouse LOCA Mass and Energy Release Model for Containment Design" March 1979 Version.

2) Letter KEW-UPRATE-04-085 dated 3-24-04 from Roy Owoc (Westinghouse) to Harv Hanneman (NMC) submitting "Applicability of WCAP 10325 to Westinghouse PWR UPI Plants"

3) Summary of Results from the UPTF Upper Plenum Injection (UPI) Separate Effects Test, Comparison to Previous Scaled Test, and Application to U.S. Pressurized Water Reactors," MPR Associates, Inc., jointly prepared by Siemens Corp (UB KWU) Erlangen, FRG and MPR Associates Washington, D.C., December 1988.

4) License Amendment Request 195 attachment 4, submitted by KNPP to NRC May 22, 2003.

8 Attachments and Parent/Child Links Evaluation (34816 bytes) by RISTE, GERALD (3/23/2004 4:32:38 PM) . 9  ;

8 Change History 3/23/2004 4:32:38 PM by RISTE, GERALD Attachment Added: Evaluation 3/23/2004 4:48:40 PM by SMITH, TIMOTHY Operability Status Changed From (None) To NA Basis for Operability Changed From " To '[Appended:] CAP written to document response to questions raised by other NMC site.

Evaluation addresses questions and acceptability of current design basis. No non-conforming condition identified. No affect on plant equipment, operation or security.'

State Changed From AR Pre-Screen To AR Screening Que Via Transition: Submit to Screening Team Owner Changed From (None) To KNPP CAP Admin Last Modified Date Changed From 3/23/2004 4:33:10 PM To 3/23/2004 4:48:40 PM Last Modifier Changed From RISTE, GERALD To SMITH, TIMOTHY Last State Change Date Changed From 3123/2004 4:33:10 PM To 3123/2004 4:48:40 PM Last State Changer Changed From RISTE, GERALD To SMITH, TIMOTHY 3/24/2004 3:23:48 PM by VANVALKENBURG, TERRY Significance Level Changed From (None) To D Last Modified Date Changed From 3/23/2004 4:48:40 PM To 3/24/2004 3:23:48 PM Last Modifier Changed From SMITH, TIMOTHY To VANVALKENBURG, TERRY Prescreen Comments Changed From " To '[Appended:] Close to Actions Taken' 3/24/2004 3:36:38 PM by HOLLY, JOHN Last Modified Date Changed From 3/24/2004 3:23:48 PM To 3/24/2004 3:36:38 PM Last Modifier Changed From VANVALKENBURG, TERRY To HOLLY, JOHN Attachment Added: Technical Evaluation of Applicablity of WCAP 10325 Methodology 3/24/2004 3:37:01 PM by HOLLY, JOHN Last Modified Date Changed From 3/24/2004 3:36:38 PM To 3/24/2004 3:37:01 PM Attachment Added: Technical Evaluation of Applicablity of WCAP 10325 Methodology httn:/IenwsO02/tmtrack/tmtrack.dll ?IssuePaae&TemDlate=viewbodv&recordid=589138&ta ... 3/25/2004