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4 UNITED ST ATES
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NUCLEAR REGULATORY COMMISSION i
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j WASHINGTON, D. C. 20556 JUN 0 31911 Docket No. 50-561
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MEMORANDUM FOR: Domenic B. Vassallo, Assistant Director for Light
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Water Reactors, DPM l
FROM:
Richard H. Vollmer, Assistant Director for Site l
Analysis, DSE i
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SUBJECT:
REVISED AAB SER INPUT FOR B-SAR-205 Standard Review Plan 15.1.5 identifies three different scenarios where i
the radiological consequences of steam line breaks should be considered.
OurpreviousAABSERinput(January 11,1977) addressed two of these i
but did not include the effects of a postulated steam line break with a stuck rod. We have analyzed the steam line break accident for this case. We have also considered the radiological consequences of a locked-rotor accident.
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We conclude that no revision to the standard technical specifications on steam generator leakage, primary or secondary coolant activities, i
will be required in consideration of either of these events. Our l
revised SER input is enclosed.
Changes are noted in the. margin or by hand corrections.
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/M-i ichard H. Vollmer, Assistant Director for Site Analysis l
Division of Site Safety and j
Environmental Analysis i
Enclosurc~.
Revised AAB SER Input l
for B-SAR-205 cc: wo/ enclosure W. Mcdonald J. Panzarella P. Shuttleworth w/ enclosure l
See next page i
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8201190602 810403 PDR FOIA MADDEN 80-515 PDR f
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Domenic B. Vassallo
,2 JUN 0 S B77 l
cc: w/ enclosure S. Itanauer H. Denton D. Muller l
F. Miraglia l
J. Miller l
R. Boyd L. Crocker
- 0. Parr T. Cox R. Vollmer D. Bunch G. Chipman J. Wing l
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cubic meter (30 meter elevated release) or less at tha cearmt exclusion area boundary will be required in order to meet the 150 rem thyroid dose guideline value for Case 2.
For sites with poorer dispersion conditions, lower primary to secondary steam generator tube leak rate technical specifications may be required.
I 15.X.4 Steam Generator Tube Failure and Steam Line Failure
. The assumptions used in the analysis of the. steam generator tube.
failure and steam line f ailure accidents are' listed in Tables 15-4, 15-5, and 15-6.
I 7t.e resulting doses for these accidents are listed in Table 15-1 for a relative' concentration of 4 x 10 seconds per cubic meter.
These doses were calculated based on the maximum activity con-~
centrations in the primary and secondary coolants specified in the technical specifications for recent Babcock and Wilcox plants.
For plants of the B-SAR-205 size the coolant activity, limits may have to be lowered in order to assure that the doses for these - --
-r accidents do not exceed appropriately low fractions of 10 CFR 100 for sites with strcspheric dispersion values higher than 4 x 10 seconds per cubic ceter.
15.X.5 Re' actor Coolant Pump Rotor Seizure The event postulated is an instantaneous seizure of the rotor of a reactor coolant pump.
Flow through the affected loop is-rapidly i
reduced, leading to a reactor and turbine trip. The sudden decrease in core coolant flow while the reactor is at power results in a degra-dation of core heat transfer which for B-SAR-205, is calculated to result in fuel damage to 4.8% of the core, i
On the basis of our experience with the evaluation of similar accidents for plants of similar design, we have concluded that the consequences of this accident can be controlled by limiting the permissible primary to secondary coolant leak rate so that potential offsite doses are small. i We will include appropriate limits on the primary to secondary leakage j
in the technical specifications for plants referencing B-SAR-205.
TABLE 15-1 RADIOLOGICAL CONSEQUENCES OF DESIGN BASIS ACCIDENTS
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2-hour Dose 2-hour Dose to Thyroid (rem) to Uhole Body (rem)
<1 26 Steam Generator Tube failure Steam Generator Tube Failure with
<1 129 Coincident lodine Spike
< 0.1 6.3 j
Steam Line Failure Steam Line Failure with Coincident'
< 0.1
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11 Iodine Spike
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Steam Line Failure with Stuck lod' 44
< 0.1 16
<1
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Rod Ejection - Case 1 78
< 0.1 i
Case 2 l
l 6.6 150 J
Loss of Coolant For an assumed relative concentration o[ 4 x 10 seconda per cubic metar.
1 2 rem - roentgen equivalent man Case 1 assumes all releases through the containment.
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t case 2 assumes all releases through the secondary system.
TABLE 15-2 i
ASSUMPTIONS USED IN THE ESTIMATE OF LOSS-07-COOLANT ACCIDENT DOSES 4100 megawatts 1.
Thermal power level 3.0 years 2.
Operating Time 0.10 percent.
Reactor Building Leak Rate (0-24 hours) l 3.
(>24 hours) 0.05 percent.
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Iodine Composition l
91 percent Elemental 5 peseent Ibrticulate
& Percent Organic Two-Hour Thyroid Dose Reduction Factor for 5.5 5.
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TABLE 15-4 (Cont 'd.)
'19.
All ra12 coco thrsugh tha escondary cystro (cxc pt Rod Ejsctirn Accident, Case 1).
20.
For accidents assumed to occur in coincidence with an iodine spike, the primary coolant concentration is as limited lyr the standard Technical Specifications for 48-hour periods (CD microcuries per gram I-131 equivalent at 100 percent power}.
21.
10 percent of iodine and noble gases fut1 activity in gaps,.
TABLE 15-5 2
s ASSUMPTIO3S USED IN ANALYSIS OF STEAM GENERATOR TUBE FAILURE ACCIDENT 1.
Isolation of failed steam generators within 30 minutes of accident.
2.
Steam generators controlled at safety valve settings.
3.
,No more than 130,000 pounds of primary coolant are transferred to the i
secondary side of the faulty steam generator following the accidant.
4.
Pressure equalization between defective steam generator and primary i
system reached within 30 minutes.
TABLE 15-6 ASSUMPTIONS USED IN ANALYSIS 0F STEAM LINE FAILURE ACCIDENT
.1.
Steam line isolation valves fully close within 10 sec.onds of break.
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.2.
Only one steam generator blows down even if one of the isolation valves fail to close.
3.
Contents of one steam generator (44,000 pounds of water and 6,000 pounds of steam) released to environment as steam within 30 seconds.
4.
One~parcent of the fuel rods experience cladding failures (DMBR<1.30) for' case of one stuck rod.
5.
All iodine in the failed SG initially and resulting from tube leakage, is released to the environment.
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