ML19317G950
| ML19317G950 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 03/21/1977 |
| From: | Matstimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | Reid R Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8004020609 | |
| Download: ML19317G950 (3) | |
Text
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U.s. NUCLEAD I;ECULATCOY Cy 'HS8loN OoCKET NUM ben.
NRCp RM G.
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5;-312
/NRC DISTRIBUTION con PART 50 DOCKET MATERIAL TO:
FROM:
oATE oF DOCUMENT Sacramento Municipal Utility Dist'.
3/21/77 Sacramento, California
$/77 Mr. Robert W. Reid J. J. Mattimoe gETTE R ONOTORIZED PROP INPUTPoRM NUMSER oF COPIES RECElVED J
DCmGINAL JRUNCLASSW E D OCopy One signed DESCf:lPTioN ENCLOSURE
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Ltr. re our 1/17/77 ler..trans the following:
Evaluation of a fuel handling accident
- DO NOT REM 0YB.
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PLANT NAME-f p Rancho Seco Unit No. 1 RJL SAFETY FOR ACTION /INFORMATION pytrTon ASSIGNED AD:
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/ BRANCH CHIEF?
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PROJECT MANAGER:
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SYSTEMS SAFETY PLANT SYSTEMS SITE SAFETY &*
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$SMUD SACRAMENTO MUNICIPAL UTILITY DISTRICT O 6201 S street, Box 15830, Sacramento, California 95813; (916) 452-3211 EM1DXIBGCETLLC0g Director of Nuclear Reactor Regulation
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Attention: Mr. Robert W. Reid, Chief d/(i.
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U. S. Nuclear Regulatory Commission 1'
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20555 s., -
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Docket No. 50-312 hci",.
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Rancho Seco Nuclear Generating C/
Station, Unit No.1
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Dear Mr. Reid:
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Your letter of January 17, 1977 requested an analysis of a fuel handling accident inside the reactor containment building to show that radiation exposures due to such an a'ccident would be within the exposure guidelines of 10 CFR Part 100.
The enclosure to this letter provides this analysis based on an earlier analysis provided in the Rancho Seco Unit No.1 Environmental Impact Report, Section 8.5.6.
Several changes have been made to this earlier analysis so that the assumptions are com-parable to those given in Regulatory Guide 1.25, " Assumptions Used for Evaluating the Potential Radiological Consequences of a Fuel Handling Accident in a Fuel Handling and Storage Facility for Boiling and Pressur-ized Water Reactors."
On February 3,1977, the Sacramento Municipal Utility District proposed an Amendment No. 32, Revision 2, to its operating license, DPR-54, to bring the facility ventilation system Technical Specifications into agreement wherever possible with the latest Standard Technical Specifica-tions. These proposed Technical Specifications eliminated any requirement for testing the reactor building purge filtering system.
The enclosed analysis shows that reactor building purge filters are not required to keep radiation exposures resulting from a fuel handling accident inside the containment within the guidelines of 10 CFR Part 100. Therefore, the District does not propose any additional changes to the Rancho Seco Unit No.1 Technical Specifications at this time.
Sincerely yours,
.MNh J.
. Mattimoe Assistant General Manager and Chief Engineer Enclosure
/
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EVALUATION OF A FUEL HANDLING ACCIDENT INSIDE THE REACTOR CONTAINMENT BUILDING I.
INTRODUCTION:
A fuel handling accident is highly improbable in either the reactor containment building or the fuel storage building. This type of accident for the fuel storage building was analyzed in the Final Safety Analysis Report and Safety Evaluation for Rancho Seco Unit No. 1.
The resulting offsite radiation exposures were shown to be well within the guidelines of 10 CFR Part 100.
The Environmental Impact Report for Rancho Seco Unit No.1 presented analyses for fuel handling accidents as a Class 6 event (inside the containment building) and as a Class 7 event (outside the containment building). The assumptions used for the analyses in the Environmental Impact Report are more realistic than the conservative assumptions required by Regulatory Guide 1.25.
The analysis outlined below is based upon the analysis contained in the Rancho Seco Unit No.1 Environmental Impact Report with changes made to the assumptions utilized so they are comparable to those in Regulatory Guide 1.25.
II.
DESCRIPTION:
The following assumptions were utilized in this analysis to evaluate irradiation exposures at the site boundary and at the low population zone distance resulting from a fuel handling accident inside the reactor containment building:
A.
An entire fuel assembly is damaged such that the cladding on all 208 fuel pins is ruptured.
B.
The accident occurs 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> after reactor shutdown.
This is the minimum time allowed before fuel handling by the Rancho Seco Unit No.1 Technical Specifications.
C.
The fission product inventories are based on full power operation at the end of core life immediately proceeding shutdown with a radial peaking factor of 1.7.
D.
All gap activity is released from the ruptured fuel pins giving the following source strength:
Kr-85 7,143 Ci Xe-131m 488 Ci Xe-133 39,603 Ci I-131 7,037 Ci i
E.
Ninety-nine percent (99%) of the total iodine released from the damaged rods is retained by the pool water.