ML13312A665
| ML13312A665 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 03/01/1993 |
| From: | Marsh W SOUTHERN CALIFORNIA EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9303090434 | |
| Download: ML13312A665 (8) | |
Text
Southern California Edison Company 23 PARKER STREET IRVINE, CALIFORNIA 92718 WALTER C. MARSH March 1, 1993 TELEPHONE ASSISTANT MANAGER.
(714) 454-4403 NUCLEAR REGULATORY AFFAIRS U. S. Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555 Gentlemen:
Subject:
Docket Nos. 50-206, 50-361, and 50-362 Annual RCS Specific Activity Report - 1992 San Onofre Nuclear Generating Station, Units 1, 2, and 3 This submittal provides the Annual Reactor Coolant System (RCS)
Specific Activity Report for calendar year 1992.
This report is required by Technical Specifications (TS) 6.9.1.5 to Facility Operating License Nos.
DPR-13, NPF-10, and NPF-15 for San Onofre Units 1, 2, and 3, respectively.
This letter reports two instances in which RCS specific activity exceeded the limits of Technical Specifications 3.1.1 and 3.4.7 for Units 1 and 3 respectively. Also included is information concerning a Unit 1 sample result which indicated elevated iodine levels during mode 5 operations.
There were no instances in 1992 in which Unit 2 RCS specific activity exceeded TS limits.
If you require additional information, please let me know.
Sincerely, Enclosures cc: J. B. Martin, Regional Administrator, NRC Region V S. W. Brown, NRC Project Manager, San Onofre Unit 1 M. B. Fields, NRC Project Manager, San Onofre Units 2 & 3 C. W. Caldwell, NRC Senior Resident Inspector, San Onofre Units 1,2,& 3 R. F. Dudley, Section Chief, Non-Power, Decommissioning, and Environmental Project, Directorate of Reactor Project 3,4,& 5 9303090434 930301 PDR ADOCK 05000206 R
1992 RCS Specific Activity Report Southern California Edison Company San Onofre Nuclear Generating Station, Units 1, 2, and 3 Docket Nos. 50-0206, 50-361, and 50-362 On September 17, 1992, at 0420 with Unit 3 in Mode 3, following a planned reactor shutdown, analysis of a Reactor Coolant System (RCS) sample indicated that RCS specific activity exceeded 1.0 microcurie/gram Dose Equivalent (DE) 1-131 due to iodine spiking. A combination of purification system operation and iodine isotope decay resulted in reducing the RCS specific activity below 1.0 microcurie/gram DE 1-131 on September 17, 1992 at 1118. The RCS specific activity exceeded the DE 1-131 limit for approximately 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and 58 minutes.
On November 30, 1992, at 1017 with Unit 1 in Mode 3, following a planned shutdown at the end of fuel cycle 11, analysis of a RCS sample indicated that RCS specific activity exceeded 1.0 microcurie/gram DE 1-131 due to iodine spiking. Between the approximate times of 1440 and 1810 the RCS was depressurized from normal operating pressure to approximately 550 psig as part of normal plant shutdown to Mode 5. This depressurization caused iodine levels, which were still above 1.0 microcurie/gram but decreasing, to increase substantially. A combination of purification system operation and iodine isotope decay resulted in reducing the RCS specific activity below 1.0 microcurie/gram DE 1-131 on December 2, 1992 at 0135. The RCS specific activity exceeded the DE 1-131 limit for approximately 39 hours4.513889e-4 days <br />0.0108 hours <br />6.448413e-5 weeks <br />1.48395e-5 months <br /> and 18 minutes.
On December 6, 1992 at 0335 with Unit 1 in Mode 5, an RCS sample was taken to determine effectiveness of a crud burst clean-up in progress. Although sampling for iodine is not required during mode 5 operations, iodine is counted as part of any RCS sample that is collected for activity analysis.
The results of this sample analysis indicated that DE 1-131 was above 1.0 microcurie per gram. The increase in iodine activity was a result of depressurization of the RCS from a solid plant condition at approximately 350 psig to a condition with the pressurizer at 70% level and vented to the pressurizer relief tank. A combination of purification system operation and iodine isotope decay resulted in reducing the RCS specific activity below 1.0 microcurie/gram DE 1-131 on December 6, 1992 at 1232. The RCS specific activity exceeded the DE 1-131 limit for approximately 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> and 57 minutes.
Enclosed for each occurrence are summary pages which include specific activity, power, and purification flow rate histories.
Also included are graphs of iodine concentrations during the covered periods.
1992 RCS Specific Activity Report Southern California Edison Company San Onofre Nuclear Generating Station, Units 1, 2, and 3 Docket Nos. 50-206, 50-361, and 50-362 Unit 1 Reactor Coolant System Specific Activity (uCi/gram)
Date/Time of Sample DE 1-131 1-131 1-133 11/29/92, 0828 0.130 0.082 0.120 11/30/92, 1017 2.950 2.350 1.920 11/30/92, 1415 2.190 1.790 1.280 11/30/92, 1810 7.200 6.080 3.760 11/30/92, 2200 7.210 6.210 3.440 12/01/92, 0025 6.950 6.060 3.100 12/01/92, 0425 4.890 4.340 1.970 12/01/92, 0820 3.100 2.790 1.120 12/01/92, 1215 2.320 2.110 0.750 12/01/92, 1615 1.660 1.520 0.495 12/01/92, 2015 1.370 1.270 0.361 12/01/92, 2128 1.290 1.190 0.331 12/02/92, 0135 0.932 0.870 0.211 Reactor Power History 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> prior to exceeding 1 uCi/gram DE 1-131 Time Period Reactor Power 11/28/92, 1000 to 11/28/92, 1900 91%
11/28/92, 1900 to 11/29/92, 0245 91% decreasing to 72.5%
11/29/92, 0245 to 11/29/92, 0437 72.5%
11/29/92, 0437 to 11/30/92, 0501 72.5% decreasing to 0%
11/30/92, 0501 to 12/02/92, 0135 0%
Purification Flow History 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> prior to to exceeding 1 uCi/gram DE 1-131 Time Period Purification Flow Rate 11/28/92, 1000 to 11/30/92, 0601 90 GPM 11/30/92, 0601 to 11/30/92, 2015 90 GPM decreasing to 55 GPM*
11/30/92, 2015 to 12/02/92, 0135 90 GPM
- Purification flow rate decreased as RCS pressure was lowered during cooldown to mode 5, until RHR was placed inservice at 2015 on 11/30/92 at which time flow rate was increased to approximately 90 GPM. Flow rates are based on known plant conditions and observed readings.
1992 RCS Specific Activity Report Southern California Edison Company San Onofre Nuclear Generating Station, Units 1, 2, and 3 Docket Nos. 50-206, 50-361, and 50-362 Unit 1 Reactor Coolant System Specific Activity (uCi/gram)
Date/Time of Sample DE 1-131 1-131 1-133 12/05/92, 1757 0.731 0.731 0.013 12/06/92, 0325 1.580 1.580 0.019 12/06/92, 1232 0.775 0.773 0.007 Reactor Power History 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> prior to exceeding 1 uCi/gram DE 1-131 Time Period Reactor Power 12/04/92, 0200 to 12/06/92, 1232 0%
Purification Flow History 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> prior to to exceeding 1 uCi/gram DE 1-131 Time Period Purification Flow Rate 12/04/92, 0200 to 12/06/92, 1232 55 GPM*
Purification flow rate is an approximate value.
1992 RCS Specific Activity Report Southern California Edison Company San Onofre Nuclear Generating Station, Units 1, 2, and 3 Docket Nos. 50-206, 50-361, and 50-362 Unit 3 Reactor Coolant System Specific Activity (uCi/gram)
Date/Time of Sample DE 1-131 1-131 1-133 09/16/92, 1000 0.368 0.031 0.014 09/17/92, 0420 1.244 0.988 0.818 09/17/92, 0810 1.003 0.819 0.616 09/17/92, 1118 0.796 0.662 0.455 Reactor Power History 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> prior to exceeding 1 uCi/gram DE 1-131 Time Period Reactor Power 09/15/92, 0400 to 09/16/92, 1800 99%
09/16/92, 1819 to 09/17/92, 0051 99% decreasing to 15%
09/16/92, 0051 to 09/17/92, 1118 0%*
- Reactor manually tripped per procedure.
Purification Flow History 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> prior to to exceeding 1 uCi/gram DE 1-131 Time Period Purification Flow Rate**
09/15/92, 0400 to 9/17/92, 0200 36 GPM 09/17/92, 0200 to 9/17/92, 1200 70 GPM
- Average flow rates over time periods listed. Data obtained from the Plant Monitoring System computer.
Unit 1 RCS Specific Activity 8.000 7.000 RCS Dpapressurized
_+L 6.000 5.0 0 0.-...........
E 5.000 0
4
/000 S3.000 2.000 -
1.000 -- -
0.000 1
00:00 12:00 00:00 12:00 00:00 12:00 00:00 12:00 11/29/92 11/30/92 12/01/92 12/02/92 El DE 1-131..-
+--
1-131 e-1-133
Unit 1 RCS Specific Activity 2.000 1.8 0 0 - ---------
1.600 1.400 1200 01000r 0
.8 0 0 -
0.600-0.4 0 0 -
O.200E O.000 '
12:00 18:00 00:00 06:00 12:00 18:00 00:00 06:00 12:00 12/05/92 12/06/92 12/07/92
-E-DE 1-131.- +-.
1-131 1-133
Unit 3 RCS Specific Activity 1.400I 1.200 1.000 --
E 0.800 0.600 0.400 K
0.200 0.000 00:00 06:00 12:00 18:00 00:00 06:00 12:00 18:00 00:00 09/16/92 09/17/92
-E-DE 1-131 -+-
1-131
-+-
1-133