ML20154G762
| ML20154G762 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 05/10/1988 |
| From: | Tucker H DUKE POWER CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| NUDOCS 8805250078 | |
| Download: ML20154G762 (7) | |
Text
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Duxe POWER GoxPm P.O. HOX 30180 CIEARLOTTE. N.C. 28242 HALD. TUCKER TELEPHONE vera reessnart (704) 073-4531 mamas emoot cTron May 10, 1988 U.S. Nuclear Regulatory Commission Document Control Desk Washington, D.C.
20555
Subject:
McGuire Nucicar Station Docket Nos. 50-369, -370 Clarification of Liq' aid Waste Effluent Monitoring Requirement Gentlemen:
By letter dated June 5, 1987, the NRC issued Amendment No. 72 to the Facility Operating License NPF-9 and Amendment No. 53 to Facility Operating License NPF-17 for McGuire Nuclear Station, Units 1 and 2.
The amendments consisted of changes to Technical Specifications requested by Duke Power Company letters dated March 19, 1986 as supplemented December 3, 1986 and June 4, 1987.
The change added another discharge point from the Conventional Wastewater Basin into tne Catawba River. This change was accomplished by deleting an existing footnote from Technical Specification Figure 5.1-4 which authorized a one-time discharge to the Catawba River on June 20, 1986.
The Technical Specification change did not de-crease the existing monitoring requirements (TS 3.3.3.8 and referenced TS Tcble 3.3-12) which assures instantaneous radioactive release rates remain within 10CFR 20, Appendix B Limits, and that radioactive effluent monitoring instru-mentation remains operable or appropriate compensatory action be taken.
At that time Duke also committed to maintaining a lower limit of detection (LLD) of 0.1 pCi/L or less for Cs-137.
Subsequently during a teleconference with NRC Staff on June 8, 1987 and again on October 13, 1987 it was agreed that the NRC will evaluate the methods of imple-menting the dose design objectives of 10CFR Part 50, Appendix I as provided by Duke.
It was also concluded that the LLD value at the discharga point should be determined based on the annual continuous release bases.
Duke could take into account the dilution factors available prior to the release point outfall, and that the dilution factor for the Catawba River could not be used unless a dif fuser was installed in the river at an appropriate location.
It is Duke's intention by way of the attachment to this letter to demonstrate compliance with monitoring requirements and change the previously committed LLD of 0.1 pCi/L or less for Cs-137 to 5.0F-8 microCi/ml or less for Cs-137.
Should you hr, e any questions concerning this matter, please contact S.E.
LeRoy at (704)?73-6233.
Very truly yours,
/
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900 0
Hal B. Tucker SEL/237/jge
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Attachment 8805250078 GS0510
^
PDR ADOCK 05000369 P
Document' Control Desk EMay 10, 1988
.Page 2 t
xc:
Dr. J. Nelson Grace
. Regional Administrator, Region II U.S.. Nuclear Regulatory Commission 101 Marietta St., NW, Suite 2900 Atlanta, GA 30323 Mr. Darl Hood U.S. Nuclear Regulatory Commission Office of Nuclear Reactor: Regulation i
Washington, D.C.
20555 Mr. W.T. Orders NRC Resident Inspector 1
McGuire Nuclear Station 1
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Document Control Desk May 10, 1988 Page 3 bxc: M.L. Birch J.W. Foster W.A. Haller C.L. Harlin R.M. Glover T.L. McConnell M.D. McIntosh R.O. Sharpe N.A. Rutherford R.L. Gill S.A. Gewehr P.B. Nardoci J.B. Day MC-801.02 (14)
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ATTACHMENT Clarification of Liquid Waste Effluent Monitoring Requirements at McGuire Nuclear Station 4
Duke Power Company will take the following measurements with the sensitivity nec-essary to assure that concentrations are below the levels needed. for compliance with the dose design objective of 10CFR Part 50 Appendix I by:
1)
Increasing the sample count time to achieve an LLD of 5.0E-8 microci/ml for Cs-137; 2)
Providing the dilution flow from the Waste Water Collection Basin (WWCB) (see attached Flow Schematic), a factor of 5.5 is credited for the calculation.
'ihis factor is based on an estimated annual average flow of 282 gpm from the Conventional Waste Water Treatment (WC) system and 1556 gpm from the WWCB (i.e., 1556 gpm divided by 282 gpm = 5.5); and, 3)
Controlling the total release time to a total of 4380 hours0.0507 days <br />1.217 hours <br />0.00724 weeks <br />0.00167 months <br /> per year from the WC system.
This release time control will provide a factor of h (i.e.,
8760 hr/yr - divided by 4380 hr/yr 2.0).
The total release time can be
=
increased, if necessary, by providing further increases in dilution flow from the WWCB, (Base = 1556 gpm), and by reducing the release rate from WC System (Base = 282 gpm).
l Therefore, by using the controls stated above, an LLD value of 4.5 E-9 microCi/ml for Cs-137 results at the outfall of the discharge point; thus, this value is lower than the calculated LLD of 6.5E-9 microC1/mi required to meet the 10CFR Part 50, Appendix 1 dose objectives.
Base' on Regulatory Guide 1.109, Revision 1, October 1977, "Calculation of Annual Doses to Man From Routine Releases of Reactor Effluents for the Purpose of Evalu-ating Compliance with 10CFR Part 50, Appendix I",
there are four principal expos-ure path 6.ays in the aquatic environment for estimating radiation exposure to man.
The following pathways and calculations are described in detail in Appendix A of the presiously mentioned guide:
Note Expressions are described in detail on pages 1.109-3 and 1.109-4 of REG GUIDE 1.109, Rev 1, Oct 1977.
a.
Potable Water (Equation No. 1) i U M AP P
= 1100 qp eXP(-A tp)
R,p i
i aipj g
b.
Aquatic Foods (Equation No. 2)
U M aP P R,p3 - 1100 QB D exp(- A t )
g
l~
' c.
Shorelipe Deposits (Equation Nc. 3)
U MW ap p Q T D,fpj [exp(- A tf p)][1 - exp(-A t R,p = 110,000 I "" '
f gb y
d.
Irrigated fcods - The Catawba River is not used for irrigation of gardens; therefore, this pathway for exposure to man is not applicable.
Fora particular radionuclide, the concentration in the water at the discharge point is:
REG GUIDE 1.109 Ciw = 1100(QMp/F)exp(- A tp)
Page 1.109-12 For Cs-137:
A1 = 2.636E-6 hr" For McGuire:
Mp (mixing ratio) = 1 3
F(discharge flow f t /sec) = 1838 gpm x min /60 sec x 0.13368 f t fg,g
= 4.10 ft /sec Other factors: t = 12 hr (potable water)
Table E-15, p = 24 hr (fish)
REG GUIDE 1.109 0 hr (shoreline deposits)
Page 1.109-69
=
Since exp(-A t ) approximately equals 1.0; therefore, g p 0
Cw = 1100 268.3Q (Equation No. 4)
=
4.10 The combination of equation (1) and (2) leads to the equation below:
(NOTE: Dose from shoreline deposits is negligible)
R,p
[1100 U,p p qp
,xp(_7 t ) ),.[1100 U,p p QB D exp(-A t )]
M M
=
g For Cs-137:
R,p = (1100 (QM /F)exp(- A t )](U,pD
+U D
B]
p g p Therefore: R
> Cw(U D
+U D
B]
(Equation No. 5)
Where: R
= total annual dose, in mrem /yr; Cv
= the concentration of radionuclide, in pCi/L; U,p = 21 Kg/yr - fish; i
y 43-U,p = 730 L/yr - drinking water, TABLE E-3, page 1.109-40; D,
= 7.14E-5 mrem /pC1, TABLE E-11, page 1.109-57; B
= 2000 pCi/kg per pCi/ liter, from TABLE A-1, page 1.109-13; p
R
= Cw 730 L/yr x 7.14E-5 mrem /pCi + 21 kg/yr x 7.14E-5 GRem/pci x 2000 pCi L apj kg. pCi
= 3.05 Cw Therefore:
R,
= 3.05 Cw ; and, R
3 mrem /yr per unit, Appendix I Design Objectives for apj Dose to total body from all pathways; Therefore, Cw = 0.98 pC1/L Since Cw a 268.3 Q Equation (4), then 0.98 Q
Ci/yr = 3.65E-3 Ci/yr 268.3 The LLD for the concentration in the WC system ef fluent WITHOUT DILUTION should be:
(3.65E-3 C1/yr)(1.0E+6 microCi/C1)(1 yr/365 d)(1 d/24 hr)(1 hr/60 min)(1 min /282 gal)(1 gal /3.7853L)(1 L/1000 mL) = 6.5E-09 microci/mi to meet 10CFR50 criteria.
Therefore, the LLD for the WC system effluent concentration with DILUTION should be:
6.5E-09 microci/mi x 5.5 x 2 - 7.15E - 08 microC1/ml to meet 10CFR50 criteria.
The value of 7.15E-08 microCi/ml should be considered as the minimum detectable concentration required at the discharge point into the Catawba River.
Therefore, to meet 10CFR50 criteria Duke plans to increase sample count time (see Method No.
- 1) to achieve an LLD of 5.0E-8 microCi/ml.
Therefore, the calculation above demonstrates that Duke will meet the dose design objective of 10CFR Part 50, Appendix I by implementing the methods discussed.
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