View source for DCL-16-105, 10 CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for Peak Cladding Temperature for 2015

{{Adams
| number = ML16292A889
| issue date = 10/18/2016
| title = 10 CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for Peak Cladding Temperature for 2015
| author name = Welsch J
| author affiliation = Pacific Gas &amp; Electric Co
| addressee name = 
| addressee affiliation = NRC/Document Control Desk, NRC/NRR
| docket = 05000275, 05000323
| license number = DPR-080, DPR-082
| contact person = 
| case reference number = DCL-16-105
| document type = Annual Operating Report, Letter type:DCL
| page count = 7
}}

=Text=
{{#Wiki_filter:m     Pacific Gas and
~ ~*. Electric Company                                       James M. Welsch                    Diablo Canyon Power Plant Vice President, Nuclear Generation Mail Code 104/6 P. 0. Box 56 Avila Beach, CA 93424 805.545.3242 Internal: 691.3242 October 18, 2016                                                                              Fax: 805.545.4884 PG&E Letter DCL-16-1 05 U.S. Nuclear Regulatory Commission                                           10 CFR 50.46 ATIN: Document Control Desk Washington, DC 20555-0001 Docket No. 50-275, OL-DPR-80 Docket No. 50-323, OL-DPR-82 Diablo Canyon Units 1 and 2 10 CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for Peak Cladding Temperature for 2015

==Reference:==
: 1. PG&E Letter DCL-15-093, "1 0 CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for Peak Cladding Temperature for 2014," dated August 6, 2015.
(ADAMS Accession No. ML15218A626)

==Dear Commissioners and Staff:==

Pursuant to 10 CFR 50.46, the enclosure to this letter is the annual report of changes in the Westinghouse emergency core cooling system evaluation models that affect peak cladding temperature (PCT) calculations for Pacific Gas and Electric Company's (PG&E's) Diablo Canyon Power Plant, Units 1 and 2. The attachments to the enclosure prov~de a summary of the PCT margin allocations and their bases.
The PCT values remain within the 2200&deg;F limit specified in 10 CFR 50.46. Because the Unit 1 and Unit 2 best-estimate, large-break loss-of-coolant accident analyses each have a total PCT margin allocation that is currently greater than 50&deg;F, PG&E has already proposed to complete a reanalysis of both units using the Westinghouse FULL SPECTRUM' LOCA (FSLOCA') methodology and will provide the updated PCT results to the NRC by December 2018, per PG&E Letter DCL-15-093 (Reference 1). The FSLOCA' will include code methodology changes that address fuel thermal conductivity degradation.
PG&E makes no new or revised regulatory commitments (as defined by NEI 99-04) in this letter.
If you have questions regarding this submittal please contact Mr. Mark Sharp at 805-545-3031.
A member of the STARS Alliance Callaway
* Diablo Canyon
* Palo Verde
* Wolf Creek

Document Control Desk                                            PG&E Letter DCL-16-105 October 18, 2016 Page 2
: S72ely, Jam~~w~6~
Vice President, Nuclear Generation bnsm/4540 Enclosure cc/enc: Kriss M. Kennedy, NRC Region IV Administrator Christopher W. Newport, NRC Senior Resident Inspector Balwant K. Singal, NRC Senior Project Manager Diablo Distribution A member of the STARS Alliance Callaway
* Diablo Canyon
* Palo Verde
* Wolf Creek

Enclosure PG&E Letter DCL-16-1 05 10 CFR 50.46 ANNUAL REPORT OF EMERGENCY CORE COOLING SYSTEM EVALUATION MODEL CHANGES FOR PEAK CLADDING TEMPERATURE FOR 2015 Pursuant to 10 CFR 50.46, this enclosure provides an annual report of changes in the Westinghouse emergency core cooling system evaluation models that affect peak cladding temperature (PCT) calculations for Pacific Gas and Electric Company's (PG&E's) Diablo Canyon Power Plant, Units 1 and 2. This report is based on changes described in Westinghouse Letter LTR-LIS-16-29, "Diablo Canyon Units 1 and 2 10 CFR 50.46 Annual Notification and Reporting for 2015,"
dated February 18, 2016.
Attachment A contains Unit 1 small-break loss-of-coolant accident (SBLOCA) and best-estimate, large-break loss-of-coolant accident (BELOCA) PCT Margin Utilization sheets. Attachment 8 contains the corresponding Unit 2 data. There have been no changes in the SBLOCA PCT results or BELOCA PCT results for either Unit 1 or Unit 2 since the last annual update. The last annual update was provided in PG&E Letter DCL-15-093, "10 CFR 50.46 Annual Report of Emergency Core Cooling System Evaluation Model Changes for Peak Cladding Temperature for 2014," dated August 6, 2015.
The final net PCT values are listed below for each unit. Two PCT values are reported for the Unit 1 BELOCA results. The two BELOCA PCT values are labeled Reflood 1 and Reflood 2, as they represent the two distinctive PCT peaks that occur during the reflood phase for the Unit 1 BELOCA Code Qualification Document methodology. The Unit 2 BELOCA reports only one PCT value consistent with the BELOCA ASTRUM methodology.
SBLOCA                                             BELOCA Reflood 1             Reflood 2 Unit 1:   1391 oF (no change)           2049&deg;F (no change)     2124&deg;F (no change)
Unit 2:   1288&deg;F (no change)                         2125&deg;F (no change)
The PCT values remain within the 2200&deg;F limit specified in 10 CFR 50.46.
However, because the Unit 1 and Unit 2 BELOCA analyses each have a total PCT margin allocation that is currently greater than 50&deg;F, PG&E has already proposed to complete a reanalysis of both Units using the Westinghouse FULL SPECTRUMTM LOCA (FSLOCA') methodology and provide the updated PCT results to the NRC by December 2018, per PG&E Letter DCL-15-093. The FSLOCATM will include code methodology changes that address fuel thermal conductivity degradation.
1

Attachment A PG&E Letter DCL-16-105 DCPP UNIT 1 PEAK CLADDING TEMPERATURE MARGIN UTILIZATION SMALL-BREAK Loss-of-Coolant Accident                                     PG&E Letter1 Peak Cladding A. ANALYSIS OF RECORD                                        1391&deg;F       DCL-09-057 Temperature (PCT) =
B. PRIOR 10 CFR 50.46 EMERGENCY CORE COOLING SYSTEM(ECCS)MODEL ASSESSMENTS 2
: 1. None
                                               ~PCT=                ooF C. 10 CFR 50.46 ECCS MODEL ASSESSMENTS THIS YEAR
: 1. None                                                    OoF
                                               ~PCT=
D. SUM OF 10 CFR 50.46 CHANGES
      ,/
: 1. Net Sum of 10 CFR 50.46 PCT Changes                        ~PCT=                OoF
: 2. Absolute Sum of 10 CFR 50.46 PCT Changes           ~PCT=                ooF E. Analysis of Record PCT (Line A) +
Line D.1 Net Sum of                                         1391 &deg;F 10 CFR 50.46 PCT Changes The sum of the PCT from the most recent analysis of record using an acceptable evaluation model and the estimates of the net PCT effect for changes and errors identified since this analysis remains less than 2200&deg;F.
For those issues that have been previously reported under 10 CFR 50.46, a PG&E letter number is listed .
2 Only permanent assessments of PCT margin are included. Temporary PCT allocations that address current LOCA model issues are not considered with respect to 10 CFR 50.46 reporting requirements.
A-1

Attachment A PG&E Letter DCL-16-105 DCPP UNIT 1 PEAK CLADDING TEMPERATURE MARGIN UTILIZATION Best Estimate, Large Break Loss-of-Coolant Accident                               PG&E Letter1 Reflood 1     Reflood 2 A. ANALYSIS OF RECORD                            1900&deg;F          1860&deg;F         DCL-05-146 ilPCT          ilPCT B. PRIOR 10 CFR 50.46 EMERGENCY CORE COOLING SYSTEM (ECCS)
MODELASSESSMENTS 2
: 1. Revised blowdown heatup                       5&deg;F            5&deg;F          DCL-05-086 uncertainty distribution.
: 2. HOTSPOT Fuel Relocation                       10&deg;F           OoF          DCL-07-071 Error.
: 3. Replacement Steam                            75&deg;F           71oF          DCL-09-057 Generators
: 4. 230 kV Degraded Voltage Event                 ooF
* 39&deg;F         DCL-11-082
: 5. Performance and Design (PAD)                -118&deg;F         -118&deg;F         DCL-12-102 4.0 Implementation
: 6. Fuel Thermal Conductivity                    133&deg;F          238&deg;F         DCL-12-102 Degradation (TCD) and Peaking Factor Burndown
: 7. Revised Heat Transfer Multiplier              5&deg;F           -35&deg;F         DCL-13-111 Distributions
: 8. Changes to Grid Blockage and                 24&deg;F            24&deg;F         DCL-13-111 Porosity
: 9. Error in Burst Strain Application             15&deg;F          40&deg;F          DCL-14-070 C. 10 CFR 50.46 ECCS MODEL ASSESSMENTS THIS YEAR
: 1. None D. SUM OF 10 CFR 50.46 CHANGES
: 1. Net Sum of PCT Changes                      149&deg;F          264&deg;F
: 2. Absolute Sum of PCT Changes                  385&deg;F          570&deg;F E. Analysis of Record PCT (Line A) +
Line D.1 Net Sum of 10 CFR 50.46              2049&deg;F          2124&deg;F PCT Changes The sum of the PCT from the most recent analysis of record using an acceptable evaluation model and the estimates of the net PCT effect for changes and errors identified since this analysis remains less than 2200&deg;F.
For those issues that have been previously reported under 10 CFR 50.46, a PG&E letter number is listed.                                                  '
2 Only permanent assessments of PCT margin are included. Temporary PCT allocations that address current LOCA model issues are not considered with respect to 10 CFR 50.46 reporting requirements.
A-2

Attachment B PG&E Letter DCL-16-105 DCPP UNIT 2 PEAK CLADDING TEMPERATURE MARGIN UTILIZATION Small Break Loss-of-Coolant Accident                                      PG&E Letter1 Peak Cladding A. ANALYSIS OF RECORD Temperature (PCT) =           1288&deg;F    DCL-08-061 B. PRIOR 10 CFR 50.46 EMERGENCY CORE COOLING SYSTEM (ECCS)
MODEL ASSESSMENTS 2
: 1. None                                   LlPCT =             ooF C. 10 CFR 50.46 ECCS MODEL ASSESSMENTS THIS YEAR
: 1. None                                                       ooF LlPCT =
D. SUM OF 10 CFR 50.46 CHANGES
: 1. Net Sum of 10 CFR 50.46 PCT Changes                               LlPCT =             ooF
: 2. Absolute Sum of 10 CFR 50.46 PCT Changes                           LlPCT =             0&deg;F E. Analysis of Record PCT (Line A)
      + Line 0.1 Net Sum of                                       1288&deg;F 10 CFR 50.46 PCT Changes The sum of the PCT from the most recent analysis of record using an acceptable evaluation model and the estimates of the net PCT effect for changes and errors identified since this analysis remains less than 2200&deg;F.
For those issues that have been previously reported under 10 CFR 50.46, a PG&E Letter number is listed.
2 Only permanent assessments of PCT margin are included. Temporary PCT allocations that address current LOCA model issues are not considered with respect to 10 CFR 50.46 reporting requirements.
B-1

Attachment 8 PG&E Letter DCL-16-105 DCPP UNIT 2 PEAK CLADDING TEMPERATURE MARGIN UTILIZATION BELOCA                                                                         PG&E Letter1 A. ANALYSIS OF RECORD                                PCT=         1872&deg;F      DCL-07-071 B. PRIOR 10 CFR 50.46 ECCS MODEL ASSESSMENTS 2
: 1. HOTSPOT Fuel Relocation Error.              ~PCT=             ooF      DCL-07-071
: 2. 230 kV Degraded Voltage Event.               ~PCT=            16&deg;F      DCL-11-082
: 3. Fuel Thermal Conductivity                   ~PCT=          209&deg;F       DCL-12-102 Degradation (TCD) and Peaking Factor Burndown
: 4. Revised Heat Transfer Multiplier             ~PCT=           -17oF      DCL-13-111 Distribution
: 5. Changes to Grid Blockage and                ~PCT=            24&deg;F      DCL-13-111 Porosity
: 6. Error in Burst Strain Application           i\PCT=           21oF      DCL-14-070 C. 10 CFR 50.46 ECCS MODEL ASSESSMENTS THIS YEAR
: 1. None                                        ~PCT=
D. SUM OF 10 CFR 50.46 CHANGES
: 1. Net Sum of 10 CFR 50.46 PCT                 ~PCT=          253&deg;F Changes
: 2. Absolute Sum of 10 CFR 50.46                ~PCT=          287oF PCT Changes E. Analysis of Record PCT (Line A) +                             2125&deg;F Line D.1 Net Sum of 10 CFR 50.46 PCT Changes The sum of the PCT from the most recent analysis of record using an acceptable evaluation model and the estimates of the net PCT effect for changes and errors identified since this analysis remains less than 2200&deg;F.
For those issues that have been previously reported under 10 CFR 50.46, a PG&E letter number is listed.
2 Only permanent assessments of PCT margin are included. Temporary PCT allocations that address current LOCA model issues are not considered with respect to 10 CFR 50.46 reporting requirements.
* 8-2}}