ML22081A320
| ML22081A320 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 03/22/2022 |
| From: | Ameren Missouri, Union Electric Co |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML22081A318 | List: |
| References | |
| ULNRC-06725 | |
| Download: ML22081A320 (6) | |
Text
Attachment 1 to ULNRC-06725 Page 1 of 3 1
ATTACHMENT 1 CHANGES TO THE WESTINGHOUSE ECCS EVALUATION MODEL AND PCT PENALTY ASSESSMENTS to ULNRC-06725 Page 2 of 3 2
TABLE OF CONTENTS
- 1.
GENERAL CODE MAINTENANCE
- 2.
REDUCTION IN FLOW AREA TO THE BOTTOM OF THE BARREL/BAFFLE REGION to ULNRC-06725 Page 3 of 3 3
- 1.
GENERAL CODE MAINTENANCE Various changes have been made to enhance the usability of codes and to streamline future analyses.
Examples of these changes include improving the input diagnostic checks; enhancing the code output; optimizing active coding; and eliminating inactive coding. These changes represent Discretionary Changes that will be implemented on a forward-fit basis in accordance with Section 4.1.1 of WCAP-13451.
Estimated Effect Westinghouse has judged this issue to have an estimated PCT impact of 0°F on existing Small Break LOCA analysis results.
- 2.
REDUCTION IN FLOW AREA TO THE BOTTOM OF THE BARREL/BAFFLE REGION
=
Background===
For plants without holes in the edge of the lower core plate, the flow area from the bottom of the core to the barrel/baffle region has historically been modeled as the gap between the baffle plate and the lower core plate, and this flow area did not consider the reduced flow area due to the presence of the bottom nozzle flow skirt. The impact of reducing the flow area between the core and barrel baffle region due to including the bottom nozzle flow skirt has been qualitatively evaluated. This item represents a Non-Discretionary Change in accordance with Section 4.1.2 of WCAP-13451.
Estimated Effect The evaluation determined that considering a reduced flow area from the bottom of the core to the barrel/baffle region when considering the bottom nozzle flow skirt has a negligible effect on the SBLOCA analysis results, leading to an estimated peak cladding temperature (PCT) impact of 0°F.
to ULNRC-06725 Page 1 of 3 1
ATTACHMENT 2 ECCS EVALUATION MODEL MARGIN ASSESSMENT FOR CALLAWAY to ULNRC-06725 Page 2 of 3 2
LARGE BREAK LOCA A.
ANALYSIS OF RECORD (AOR)
PCT = 1939°F B.
PRIOR ECCS MODEL ASSESSMENTS
+ 58°F C.
CURRENT LOCA MODEL ASSESSMENTS -
+ 0°F March 2022 LICENSING BASIS PCT + MARGIN ALLOCATIONS 1997°F ABSOLUTE MAGNITUDE OF MARGIN ALLOCATIONS 58°F SINCE LAST ANALYSIS OF RECORD OR LBLOCA 30-DAY REPORT to ULNRC-06725 Page 3 of 3 3
SMALL BREAK LOCA A.
ANALYSIS OF RECORD (AOR)
PCT = 1043°F B.
PRIOR ECCS MODEL ASSESSMENTS
+ 0°F C.
CURRENT ECCS MODEL ASSESSMENTS -
+ 0ºF March 2022 LICENSING BASIS PCT + MARGIN ALLOCATIONS 1043°F ABSOLUTE MAGNITUDE OF MARGIN ALLOCATIONS 0°F SINCE LAST ANALYSIS OF RECORD OR SBLOCA 30-DAY REPORT