ML20035G094
| ML20035G094 | |
| Person / Time | |
|---|---|
| Site: | 05200001 |
| Issue date: | 04/22/1993 |
| From: | Fox J GENERAL ELECTRIC CO. |
| To: | Poslusny C Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9304260147 | |
| Download: ML20035G094 (2) | |
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l GENuclear Energy 4s
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Genera!Dewa Ccrww
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nb Cu::nw Avvoue. M Jux CA 95125
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l April 22,1993 Docket No. STN 52-001 l
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Chet Poslusny, Senior Project Manager Standardization Project Directorate Associate Directorate for Advanced Reactors
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and License Renewal Office of the Nuclear Reactor Regulation -
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Subject:
Submittal Supporting Accelerated.ABWR Review Schedule - DFSER Open Item 16-3
Dear Chet:
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Enclosed is the justification of three independent ECCS subsystems which addresses DFSER Open Item 16-3.
Please provide copies of this transmittal to Tim Polich.
l Sincerely, h
Jack Fox 1
Advanced Reactor Programs l
cc: Alan Beard Norman Fletcher (DOE)
CalTang (GE) 260083 7 fg 2
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l 9304260147 930422 PDR ADOCK 05200001
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ABWR CDF SENSITIVITV TO ESF DIVISIONS OUT OF SERVICE Attached are results of studies which evaluated the impa 4 on the estimated core damage frequency (CDF) for the GE Advanced Boiling Water Reactor (ABWR) of removing Engineered Safety Feature (ESF) divisions from senice duiing full power. Analyses were performed by modifying and reevaluating the ABWR Level 1 PRA fault and event tree models documented in the SSAR. Results are based on and reflect the impact of complete removal of each division of engineered safety equipment from senice, including all power, instrumentation, and senice water.
The tabulation which follows summarizes the impact on caiculated CDF for the complete removal of a division from senice for 30 days per year. Additionally, the tabulation l
shows the effect on calculated CDF for remosing a complete division from senice for the entire year. The base line CDF in the PRA is 1.56E-07 per year which assumes ECCS l
trains (RCIC, HPCF B&C, RHR A B&C) are out of senice (OOS) 2% per year (i e., I week) but not concurrently. The effect of out of senice times other than 30 days can be l
l obtained by linear interpolation between the ABWR base case value and that for each configuration ofinterest taken completely out of senice.
Although the percentage impact on CDF is significant, the estimated absolute value is still extremely low. The bounding case, i. e., Division I taken completely out of senice, yields an estimated CDF of only 2.09E-06 per year. This is a factor of five lower than the NRC safety goal.
Division I out of service prevents the initiation of RCIC and RHRA. It has the greatest i
impact on the CDF since RCIC is essential for core cooling success in the event of station blackout. Next in imponance is Disision 11 which initiates HPCFB and RHRB. The HPCFB incorporates a hard wired manual initiation feature diverse from the multiplexing network. This increases the safety importance of Division II. The least impact is seen when Division III is removed from senice, preventing the initiation of HPCFC and RHRC.
CASE DIVISION OOS 30 DAYS 7ER DIV. COMPLETELY REMOVED YEAR FROM SERVICE CDF PER YEAR % INCREASE CDF PER YEAR % INCREASE ABWR BASE CASE FROM SSAR 1.SSE-07 N/A N/A N/A
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DIVISION I OUT OF SERVICE 315E-07 102 2.09E-06 1240 DIVISION 11 OUT OF SERVICE 2.41E-07 54 1.19E-06 660 DIVISION til OUT OF SERVICE 1.92E-07 23 5 94E-07 280
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