ML13333A492
| ML13333A492 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 01/29/1980 |
| From: | Ziemann D Office of Nuclear Reactor Regulation |
| To: | James Drake Southern California Edison Co |
| References | |
| TASK-15-02, TASK-15-2, TASK-RR NUDOCS 8002140412 | |
| Download: ML13333A492 (7) | |
Text
Docket iRC PDR~
Docket No. 50-206 Local Pop, IR Reading 1M4RR READING Sisenhut Mr. James H. Drake Vice President Southern California Edison Company M
(3)
JAN 2 2244 Walnut Grove AvenueZie Post Office Box 300 KSmih Rosemead, California 91770
Dear Or. Drake:
TEA RE:
COIMPLETIOH OF SEP TOPIC XV-18 RadioloRA444944&s of i-ain steam Line Failure Outside Containoment Your letter dated December 7, 1979, indicated that you have exanined our draft evaluation of the subject topic dated November S, 1979. You suggested editorial or corrective changes to the assessment to make it more accurately reflect your facility design.
We have incorporated your suggested modifi cations in the enclosed assessment.
With these modifications our review of SEP Topic XV-18 is co,,,ylete and will be a basic input to the integrated assessment of your facility.
The subject assessment compares your facility design with the criteria currently used by the staff in licensing new facilities. This assessment may need to be re-examined if you modify your facility or if the criteria are changed before we complete our integrated assessment.
Si ncerely, Original Signed by:
Dennis L. Ziemann Dennis L. Zlemann, Chief Operating Reactors Branch #2 Division of Operating Reactors
Enclosure:
Completed SEP Topic XV-18 cc w/enclosure:
See next page OFFICE
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....T E R NRC FORM 318 (9-76) NRC 0O NT PRINTING OFFICE: 1979-289 369 Lin Faiur Outid U.S CoRntanen January 29, 1980 cc Charles R. Kocher, Assistant Director, Technical Assessment General Co.unsel Division Southern California Edison Company Office of Radiation Programs Post Office Box 800 (AW-459)
Rosemead, California 91770 U. S. Environmental Protection
- Agency, David R. Pigott CrystalMall f2 Samuel B. Casey Arlington, Virginia 20460 Chickering & Gregory Three Embarcadero Center U. S. Environmental Protection Twenty-Third Floor Agency San Francisco, California 94111 Region IX Office ATTN: EIS COORDINATOR Jack E. Thomas 215 Freemont Street Harry B. Stoehr San Francisco, California 94111 San Diego Gas & Electric Company P. 0. Box 1831 K M C, Inc.
San Diego, California 92112 ATTN:
Richard E. Schaffstall 1747 Pennsylvania Avenue, N. W.
Resident Inspector Suite 1050 c/o U. S. NRC Washington, D. C. 20006 P. 0. Box 3550 San Onofre, California 92672 Mission Viejo Branch Library 24851 Chrisanta Drive Mission Viejo, California 92676 Mayor City of San Clemente San Clemente, California 92672 Chairman Board of Supervisors County of San Diego San Diego, California 92101 California Department of Health ATTN:
Chief, Environmental Radiation Control Unit Radiological Health Section 714 P Street, Room 498 Sacramento, California 9EA14
Complete -
ised - December 31, 1979 San Onofre Unit 1 Topic XV-18 Radiological Consequences of Main Steam Line Failure Outside Containment The safety objective of this topic is to assure that the releases from this postulated event will not result in exposures in excess of the established guidelines.
The rupture of a main steam line.is considered a limiting fault not expected to take place during the lifetime of the plant.
Nevertheless, it is postulated because its consequences could include the release of significant amounts of radioactive material.
In particular, the failure of a steam line outside containment would result in the release of activity contained within the secondary system, in addition to opening a potential, albeit small path for the release of reactor coolant to the environment via postulated steam generator leaks.
An analysis of the radiological consequences of a main steam line failure at the San Onofre 1 plant has been performed following the assumptions and procedures indicated in the Appendix to S.R.P. 15.1.5, "Radiological Consequences of Main Steam Line Failures Outside Containment (PWR)." The specific assumptions made regarding the plant conditions prior to the postulated accident and the expected responses are listed in Table XV-1.
In particular, it has been assumed that the three steam generators are blown dry immediately following the accident, and that 1 gpm of reactor coolant is released directly to. the environment during the first two hours. This is in accordance with Technical Specification 3.1.4 which limits the allowable steam generator primary to secondary leakage to 0.3 gpm in any one steam generator.
In addition, it has been assumed that prior to the accident the primary and secondary coolant activities were at the maximum levels allowed by the Technical Specifications 3.1.1 and 3.4.2. An evaluation of this.
accident for the Cycle 6 Reload in March 1977 concluded that no addition al fuel clad failures would occur. The estimated site boundary doses resulting from this postulated accident (see Table XV-2) have been found to be within the 10 CFR Part 100 guidelines as specified in the Acceptance Criteria for S.R.P. 15.1.5.
On the basis of these results, we conclude that operation of the San Onofre Unit 1 Generating Station is safe with regard to a possible main steam line failure, and that the risk presented by this postulated accident is similar to that of plants licensed under current criteria.
Since the plant design conforms to current licensing criteria, this completes the evaluation of this SEP topic.
TABLE XV-1 Assumptions Made in Analysis of the Radiological Consequences of Postulated Tube Failure, Main. Steam Line Failure and Rod Ejection Accident
- 1. 103% of rated reactor power a 1387 Mwth,
- 2. Loss of offsite power following the accident.
- 3. Primary coolant activity prior to the accident of l.uCi/g of Dose Equivalent 1-131 and 100/E uCi/g of noble gases.
- 4. Iodine spiking factor of 500 after the accident.
- 5. Primary coolant activity of 60.uCi/g of Dose Equivalent 1-131 at time of accident for cases assuming a previous iodine spike.
- 6. Secondary coolant activity prior to the accident of 0.1 uCi/g Dose Equivalent 1-131.
- 7. Iodine decontamination factor of 10 between water and steam.
- 8. Meteorological conditions corresponding to a 30 meter elevated release with fumigation and 1 alsec wind speed at a distance of 282 meters (X/Q = 9.5 x 10-4 sec/m 3).
- 9. No additional fuel clad failures as a result of any of the accidents.
For the Steam Generator Tube Failure Accident
- 1. Failed steam generator is not isolated following the accident.
- 2. 50,000 lb. of primary coolant leak to the secondary side of the failed steam generator through the failed tube during the first 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> (one half during the first 30 minutes).
- 3. All releases through the secondary side safety and relief valves.
For the Main Steam Line Failure Accident
- 1. Total primary to secondary leak rateof 1. gpm.
For the Control Rod Ejection Accident
- 1. All releases through the secondary side safety and relief valves.
- 2. Total primary to secondary leak rate of 1. gpm.
TABLE XV-2 ACCIDENT DOSES AT NEAREST SITE BOUNDARY 2-hour Dose 2-hour Whole to the Thyroid Body Dose (rem)
(rem)
Tube Failure Accident 47.5 0.5 Tube Failure Accident with 129.5 0.5 Previous Iodine Spike*
Steam Line Failure Accident 13.0 0.01 Steam Line Failure Accident 22.5 0.01 with Previous Iodine Spike*
Rod Ejection Accident 1.2 0.01 Rod Ejection Accident with 2.1 0.01 Previous Iodine Spike*
- For this accident sequence it is assumed that an iodine spike was initiated some time before the accident resulting in the highest coolant activity allowed by the Technical Specifications.