ML20039D072
| ML20039D072 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 12/23/1981 |
| From: | Nichols T SOUTH CAROLINA ELECTRIC & GAS CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8112310288 | |
| Download: ML20039D072 (3) | |
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Mr. Harold R. Dmtm, Director p
Office of Nuclear Reactor Ibgulaticns U. S. Nuclear Regulatory Carmissicn Washingtcn, D. C.
20555
Subject:
Virgil C. Surtmer Nuclear Staticn Docket No. 50/395 Technical Specificaticn Radiatial linitoring
Dear Mr. Dentcn:
mis letter presmts a revisicn of the TE&G positicn, presented in a letter dated Deceber 17, 1981, cn a requested diange to the Technical Specificaticns for Virgil C. Sunmer Nuclear Staticn. She specificaticn of interest is 3.11.2.1 relating to gaseous efflusits.
In particular it relates to m estry in Table 4.11-2 refereced by surveillance requirenent 4.11.2.1.2.
Discussicns with the reviewer have resulted in sane minor changes for the sake of clarity. %e changed versial is reproduced in total for your ocnsideraticn.
t mtry in this table specifies m LID of 1he g/ ci/ml for the cxntinuous noble gas ntnitors which 10 1 x observe releases fran the main plmt vcnt md _tp/ ci/ml (for reactor building purge. We are suggesting a change to 2 x 10 Kr-85) as described in our FSAR (Pgs.
11.4-8 to 11.4-10).
She specific guldmoe for this surveillance requiremmt is found in Regulatory Gilde 1.21 Appe1 dix A, secticn A.1.C., which states that the setsitivity of gross radioactivity measuremmts should be sufficielt to permit measurement of a_ small fracticn of the activity whicf1 would result in m annual air dose of 10 millirads due to ganuna radiaticn or 20 millirads due to beta radiaticn at cr beycnd the site bomdary.
She following site specific informaticn cm be used to show canpliance with this guide.
ibtal Postulated noble gas released fran the plant = 3100 ci/yr (Final Divironmmtal Statenst (FES) Thble 4.5)
Postulated Noble gas ganna air dose = 0.23 mrad /yr M O/
(FES Table 4.9)
S Postulated Noble gas beta air dose = 0.57 mrad /yr (FES Table 4.9)
/ p 8112310288 811223' PDR ADOCK 05000395 A
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Mr. Harold R. Dmtm Page two Decmber 23, 1981 So, the postulated release at the Virgil C. Sumer Nuclear Staticn to give a 10 mrad /yr gama air dose is 5
1.34 x 10 ci/yr.
'Ihe typical main plant vmt flow is 175,388 CFM (FSAR Fig. 9.4-9)
A proposed increase of 30% to this rate will not change the cc".clusicns reached below.
@e average cxncentraticn in a release that would lead to m 10 mrad ganvra air dose is give by the ratio of yearly release and yearlytoglflow. %e average cxncetraticn =
f(10cifml. A similar calculation for beta air dose 52 x - 10 gives 42 x
/(ci/ml.
Our installed instrunnitaticn is sensitive to 2 x 10 //ci/ml which is approximately 1/20th of these cxnemtraticns. It muld thus detect 1/20th of the maxhmin allowed dose if the release persisted for an mtire year cr 1/7300th if it lasted for cne day. Since most releases will prcbably came fran the reactor purge which has a maximum flow of cnly 20,000 CFM. %e detecticn fracticn will actually be evm smaller thp//ci/ml (for Kr-85) will allow us to indicate:1 by the above calculaticns.
Clearly, a LLD of 2 x 10 detect small fractions (less than 10% - 25%) of the regulatory limit fomd in Ibgulatory Guide 1.21.
We can see no justificaticn to cause us to replace our existing mmitors with those that ccnform to the ncn site specific Standard Radiological Egflumt 'Ibchnical Specificatims naninal value of 1 x 10- j# ci/ml. mis cmclusicn is exact agreement with the positicn takm by the NBC staff cn pages 11-20 and 11-23 of the Safety Evaluaticn Report.
SCE&G ccnsiders this adequate justificaticn for our present design and requests your immediate attenticn be givm to this matter.
-Sincerely, Uus>> L -
T. C. Nichols, Jr.
JB:'ICN:tdh
s-e Pt. Harold R. Dentm Page titee December-23, 1981 oc:
H. R. Dentm' V. C. Stamer T. C. Nichols, Jr.
G. H. Fisher
' H. N. CyrtL9 H. T. Rahh D. A. Nauman M. B. M11 taker, Jr.
W. A. Williams, Jr.
. O. S. Bradhan R. B. Clary M. N. Drome A. R. Kocn G.'J. Braddick J.' K. Skolds J.'B. Knotts,-Jr.
B. A. Bursey J. C. RL20ff NPCF File