ML20054K487
| ML20054K487 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 06/29/1982 |
| From: | Vandewalle D CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| TASK-15-18, TASK-RR NUDOCS 8207020248 | |
| Download: ML20054K487 (4) | |
Text
_
O Consumers Power o is J v.ns.w.n.
Nuclear Licensing Administrator General offices: 1945 West Pamell Road, Jackson, MI 49201 *(517) 788-1636 June 29, 1982 i
i Dennis M Crutchfield, Chief Operating Reactors Branch No 5 Nuclear Reactor Regulation US Nuclear Regulatory Commission r
Washington, DC 20555 DOCKET 50-155 - LICENSE DPR '
BIG ROCK POINT PLANT - REVIEW 0F NRC EVALUATION OF SAR FOR SEP TOPIC XV-18 NRC letter dated May 20, 1982 requested Consumers Power Company to provide comments on the NRC's review of the Consumers Power Company SAR regarding SEP Topic XV-18, " Radiological Consequences of a Main Steam Line Failure Outside Containment". The enclosure provides Consumers Power Company comments to the hPC's draft evaluation.
Consumers Power Company review of the NRC's draft evaluation concludes that the Big Rock Point Plant meets the intent of current NRC criteria for MSLB outside containment since the calculate dose is in excess of the guideline only due to an assumption concerning PCS radioiodine levels which is not realistic for the plant.
It should be noted,that even though the calculated dose is in excess of the guideline, it is still more than a factor of three less than the limit imposed by 10 CFR 100.
i QUtk thy (
David VandeWalle Nuclear Licensing Administrator CC Administrator, Region III, USNRC NRC Resident Inspector-Big Rock Point pages l Q l
oc0682-0011a142 8207020248 820629 PDR ADOCK 05000155 P
a-ATTACHITIT SEP TOPIC XV-18 RADIOLOGICAL CONSEQUENCES OF MAIN STEAM LINE FAILURE OUTSIDE CONTAINMENT Big Rock Point Plant
s,.
ATTACHMENT i
Consumers Power Company has reviewed your letter of May 20, 1982 providing the staff's draft evaluation of SEP Topic XV-18 (Radiological Consequences 1
of a Main Steam Line Failure Outside Containment).
CPCo does not accept your recommendation that the plant adopt the GE Standard Technical Speci-l fications concerning iodine activity and control in the reactor coolant.
The calculation performed to determine the radiological consequences of a main steam line break outside containment was not thoroughly described in our letter of July 1, 1981 and therefore may have caused some confusion.
The calcluation involved:
1.
Using the plant Technical Specificationsto determine noble gas concen-trations (cannot exceed 0.47/E Curies /sec) and iodine concentration (less than 35 uCi/ml).
2.
Using an off-gas flow of 10 cfm (normal flow from off-gas reports).
3 Dividing the noble gas release rate by the flow to obtain off-gas concentration.
h.
Using main steam line and primary ~ coolant system flow rate (Drawing M-117 Big Rock Point P & ID's), system pressures and the ideal gas lov to determine noble gas concentration in the primary coolant and steam line.
5 Using the ORIGEN code to. determine the isotopic distribution of iodine at shutdown.
t 6.
Using the steam tables to get the iodine concentration in the primary coolant.
I 7
Using the results of the accident analysis (SAFE Code) to get blowdown time (70 seconds) and pounds released (80,700 lb).
The pounds released was divided by the blowdown time to get lb/see released.
i:
8.
Multiplying the concentration by the 1b/see released by the X/Q (8.75E-Oh, Regulatory Guide 1 3, 0-8 hr, ground level release, the site boundary is 625 motora away) to get the concenLrnLion at the uite boundary.
9 Using infinite cloud equation to get whole body dose, 10.
Using following inhalation dose equation:
r E
D(rem) = (X/Q)(BR)(t) g (Ci/sec)g(Rem /ci)g 3
Where BR = breathing rate = 3.h7E-Ohm /see t = time = 70 seconds (the blowdown time).
l (Ci/sec)g = Total Iodine Ci/see released times the percent present for each isotope (Rem /C1) = TID-lh8hh Dose Conversion Factors for Iodine l
isotope i e
v-m.
m.
--m--.-
Big Rock Point Plant SEP Topic XV-18
.i i
The results were 92 rem to the thyroid and whole-body dose of 0.65 rem. Note that the 92 rem is based on an iodine concentration of 35 pCi/ml. The iodine concentration in the primary coolant has been on the order of 10-2 NCi/ml for the last few years so that the concentration would have to increase by a factor of 3500 to get to 35 pci/ml. At about 6 pCi/ml the off-gas releases are limit-ing. This factor precludes operation at 35 pCi/ml. 'Since the normal iodine concentration is so lov, the thyroid doses resulting from this accident would be acceptable even with a concurrent spike'.
It is therefore concluded that' the intent of the current NRC criteria for a MSLB outside containment is met and that the calculated dose is in excess of the guideline only due to an imposed assumption concerning PSC radioiodine levels which are not realistic for the plant.
h I
r I
1
}
~
l i
i t
4
-v y
=
n-----
,.-7y
__r.
y,m
,y.
,,-,.4,--c
-wem
--,c-.
-n, e,
e