ML20214W969

Forwards Responses to NRC 861026 Request for Addl Info Re Util 860319 Proposed Tech Spec Change to Allow Slightly Radioactive Water to Be Discharged from Conventional Waste Sys.Figure 1 Also Encl to Identify Sys Components

ML20214W969
Person / Time
Site:	Mcguire, McGuire
Issue date:	12/03/1986
From:	Tucker H DUKE POWER CO.
To:	Harold Denton, Youngblood B Office of Nuclear Reactor Regulation
References
TAC-61179, TAC-61180, NUDOCS 8612100484
Download: ML20214W969 (11)

Text

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, DUKE POWER GOMPANY P.O. ISOX 33180 CIIARI OTrE, N.C. 28242 HA . M (7[j[g"yh"33:

December 3, 1986 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555 ATTENTION: Mr. B.~J. Youngblood, Director PWR Project Directorate No. 4

Subject:

McGuire Nuclear Station Docket No. 50-369 and 50-370 Response to RFI Regarding Radioactive Discharge From Conventional Waste Streams

Dear Mr. Denton:

On March 19, 1986 Duke Power submitted a proposed Technical Specification change to allow slightly radioactive water to be discharged from the Conventional Waste (WC) system. By letter of October 26, 1986, the Staff requested additional information. Attached ere the questions asked by the Staff, together with the responses. For clarification purposes Figure 1 has been included to identify the various components of the WC system and adjacent water sources.

If the Staff desires additional information, please contact Duke through normal Licensing channels.

Very truly yours, 4 #

Hal B. Tucker SAG /45/jgm

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Attachments 8612100484 861203 DR ADOCKOS00g9 1

Harold R. Denton o December 3,1986 Page 2 xc: Dr. J.- Nelson Grace, Regional Administrator U.S. Nuclear Regulatory Commission - Region II 101 Marietta Street, Suite 2900 Atlanta, Georgia 30323 Mr. W.T. Orders Senior Resident Inspector McGuire Nuclear Station Mr. Dayne Brown, Chief Radiation Protection Branch Division of Facility Services Department of Human Resources P.O. Box 12200 Raleigh, N.C. 27605 r

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(SAG 45) ATTACHMENT STAFF QUESTIONS AND RESPONSES Premise For Questions la Through if Radioactive liquid effluents from the McGuire Nuclear Station are now sampled, analyzed, and released by a monitored pathway. The radioactive liquids are diluted by the circulating water and released to Lake Norman. The lake provides additional dilution and delay before the radioactivity reaches the river.

Question la:

The proposed new release pathway will not have the dilution and delay provided by the lake. Discuss the provisions made for assuring that the radioactivity concentrations are sufficiently low at the proposed point of release and provide a comparative analysis of river concentrations for the proposed and existing release points.

Response

Radioactive releases from the existing monitored pathway are diluted by Condensate Cooling Water (CCW) and released to Lake Norman. However, the recirculation / buildup is included in Offsite Dose Calculation Manual (ODCM) release rate and dose calculations effectively reduces CCW dilution by a factor of 2.4. Although Lake Norman provides additional delay before radionuclide releases reach the Catawba River downstream of Cowans Ford Dam, ODCM release rate and dose calculation procedures applicable to the existing monitored release point would be unaffected by the proposed new release pathway; existing ODCM procedures are applicable to maximum individual liquid pathways for Lake Norman adjacent to the existing release point. Additionally, since the proposed new release point is downstream of Cowans Ford Dam, radionuclide releases from the new release point will not affect maximum individual pathways in Lake Norman.

The combined effect of radionuclide releases from both the existing release point and the proposed new release points downstream of the new release point on Catawba River maximum individuals shall be assessed in the future and compared to Lake Norman maximum individual doses in accordance with revised ODCM Section B4.3.1 procedures. Only maximum calculated dose values (i.e., Lake Norman maximum individual or downstream Catawba River maximum individual calculated doses) shall be used for compliance or reporting purposes. Operational history has shown that the maximum individual doses will continue to result from Lake Norman pathways.

The combined effect of both the existing release point and the proposed new release point on procedures assuring radionuclide concentrations remain 7

aufficiently low is addressed by revised ODCM Section B3.1.3. Since recirculation / buildup of radionuclides in Lake Norman is considered to increase lake concentrations by as much as a factor of 2.4, it can be shown that Catawba River concentrations downstream of Cowans Ford Dam resulting fror existing release point releases will not exceed 59% of Maximum Permissible Concentration (MPC).

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Therefore, ODCM Section B3.1.3 has been revised to limit radionuclide releases from the proposed new release point to levels resulting in less than 41% of MPC after dilution in the Catawba River flow. Thia revision assures MPC values are not exceeded downstream of Cowans Ford Dam in the Catawba River due to the combined releases of both the new and existing release points.

The ODCM revision will also add an additional equatien to Section 4.3.1 to calculate dose rates due to discharges from the WC system to the Catawba River.

The calculation will reflect the fact .that, unlike a discharge to Lake Norman via CCW, there is no recirculation associated with a discharge to the river via WC.

Therefore the sigr.a (e3 factor goes from 2.4 to 1.0.

• Question Ib:

i Discuss the applicability of existing technical specifications 3/4.11.1 to the

{ proposed action; and identify changes, if any, to your request needed to assure that the new release point in combination with the existing release point are kept within the guidelines of Appendix I to 10CFR Part 50 [i.e., pursuant to Appendix I, the releases are to be controlled so the combined doses from both i

release points (existing and proposed) do not collectively exceed the Appendix I criteria].

Response

As discussed in our response to la above, ODCM Section B4.3.1 has been revised to provide procedures to assure that the new release point in combination with the existing release point are kept within the guidelines of Appendix I to 10CFR 50.

Comparative analyses shall be performed to assure only maximum dose values are used for compliance and reporting purposes.

Question Ic:

The technical specifications should require appropriate sampling and analysis prior to each release to and from the conventional wastewater basin. The analysis should be sensitive enough to assure measurement of activity in the range of interest in Appendix I evaluations; the LLD for Cs-137 for releases from the Basin, for example, should be no greater than 0.1 pCi/1. Discuss the various sampling and analyses associated with the proposed action and identify the reasurement sensitivity for the instruments to be used.

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Response

Technical Specification 4.11.1.1.1, Table 4.11-1 lists radioactive liquid waste sampling and analysis program requirements. Each release through this release point shall comply with these technical specification requirements.

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The counting equipment is an MCA system with a Germanium detector. The laboratory performing the radiological environmental analyses has participated in a interlaboratory comparison program and has been approved by the NRC. The count room equipment and its performance have met the regulatory requirements and are periodically reviewed by the NRC and INPO Inspectors.

The LLD requirements as defined and required in Specification 4.11.1.1.1 Table 4.11-1 will be fully implemented. To meet these requirements, for example, the LLD for Cs-137 for releases from the WC system shall be no greater than 0.1 pCi/1; therefore no difficulty is anticipated.

Question Id:

Address the capability to obtain representative samples from the Conventional Wastewater Collection System.

Response

Prior to release the appropriate pond will be isolated and recirculated to ensure thorough mixing for representative sampling.

Question le:

Discuss the capability to prevent unmonitored releases to and from the Conventional Wastewater Basin.

Response

To prevent unmonitored releases from turbine building sump to the conventional wastewater system there are radiation monitors installed on each Turbine Building Sump discharge line; however, they cannot detect very low levels of tritium i

activity. The station has implemented routine sampling and analyses for tritium in the Turbine Building sumps, in the WC system, in the Sanitary Waste Treatment system and in the Standby Nuclear Service Water Pond.

To prevent unmonitored releases from the conventional waste water system, in l

addition to the routine sampling program discussed above, a continuous composite gampler is located at the discharge point to preclude unmonitored releases. Any unusual activity discovered will be investigated immediately to determine the cause and correct the problem.

Wastes from Conventional Wastewater Treatment System (WC) are initially directed to a concrete-lined initial holdup pond where primary sedimentation occurs. This 200,000 gallon capacity basin haa a retention time of from 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and acts as a surge tank to prevent overloading and subsequent degradation of effluent quality throughout the remainder of the syetem. This pond may be bypassed depending on influent quality.

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The initial holdup pond is followed by parallel stream settling ponds. These two 1.1 acre, 2.5 million gallon ponds are lined with tamped clay and are equipped for recirculation. The ponds are operated such that one pond is in service while the other is on standby. Coagulent aids may be used for settling lighter solids along with pH adjustment to neutralize or precipitate various chemical compounds.

Holdup time for each of these basins ranges from 6 to 12 days.

The wastewater then normally flows by gravity to the final holdup pond where it is aerated; retention time for this basin is 5 days. This final holdup pond is used to remove any persistent oxygen demand of the wastes. The pond has a capacity of one million gallons. Its contents may be pumped to the head of the settling basins or back to its own inlet for recirculation if the effluent does not meet the established discharge limits. The final holdup pond may be bypassed and the discharge flows by gravity or is pumped to the river if the effluent is within specifications.

NOTE: In as much as the WC system acceper influent from the turbine building sump, any primary to secondary leak may result in contamination of one of the settling basins and possibly the initial hold-up pond. In this case, the basin is isolated to allow for dilution and radioactive decay as required by NRC Technical Specifications. In addition, demineralizers and chemical additives may be used to process the waste water. Releases from the pond will comply with licGuire Technical Specifications.

Question If:

Discuss the capabilities to determine the quantities to be released so they can be 4

reflected in dose calculations.

Response

Representative samples will be taken and analyzed as discussed in the response to Ic, above. From this the total curie content can be calculated for use in the offsite dose equations given in response Ib.

Question 2:

Address the accumulation of radioactivity in the sludge in the Conventional Wastewater Basin, the frequency and method of sludge removal and disposal, the radiological concentrations and exposures projected for sludge control and procedures used to maintain these exposures ALARA.

Response

As shown in Figure 1, the Wastewater Collection Basin (formerly the Conventional Wastewater Collection Basin) is not in the WC flow path. Therefore, this response addresses sludge accumulation in the initial holdup pond, where the vast majority of sludge accumulates.

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The volume of waste being generated per year is projected to range from 8,000 to 13,500 cubic feet. McGuire accumulated approximately 8,000 cubic feet of these materials in the initial holdup pond this year which was landspread in mid-October at the station landfarming site under Station Radioactive Material License No.

060-379-5 and State Department of Natural Resources and Community Development permit number 7641R2 provisions.

The radiological concentrations of the sludge are limited, as addressed in the State Radioactive Material License (No. 060-379-5). For example, Cs-137 is limited to no greater than 1.19 pCi/cc and Co-60 is limited to be no greater than 0.5 pCi/cc. The annual exposure from landfarming of this sludge is projected to be less than 1 mrem.

i Because the sludge is slow to dry, it is unsuitable for landfilling, where the waste must be covered with soil the same day it is deposited. It is preferable to landspread the sludge at a suitable site and incorporate it into the soil after it has dried. The dieposal procedures which are already approved for use by the state under Landfarming permit are as follows:

Transportation Procedure o To remove this sludge, the pond is drained and the sludge is dredged from the bottom and transferred by dump truck to the disposal site, o

The sludge will be transported to or from the disposal site in such way that liquid or solid spills will be kept to a minimum, o The preparation and shipment of radioactive material will be in accordance with station Health Physics procedures and station directives.

Disposal Procedure o During and after the disposal process access to the proposed disposal site will be controlled. Proper warnings will be maintained as described in the Landfarming permit.

o The waste sludge (water treatment residues) will be spread on the surface of the proposed disposal site over an approximate area and depth of one acre and six inches, respectively.

o The sludge will be incorporated approximately six inches into the soil after drying to the extcnt practical. Because of water retention by the resins, there will be nc halation hazard from diatomaceous earth particles.

o A suitable year round vegetative cover will be established and maintained after the waste has been incorporated and covered with topsoil as needed, if necessary.

o The workers handling the waste disposal will be properly dressed in accordance with station Health Physics procedures and station directiven.

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~6-Administration Procedure o The waste volume of each batch disposed of will be properly estimated and documented.

4 o For each batch of waste generated, a composite sample from different locations will be taken for radiological analysis, and results will be documented.

o The total waste volume and radioactivity inventories will be documented,

and the total accumulating dose will be periodically evaluated.

3 o The disposal rates will be limited to 500 cubic yards per year (6 inches / acre / year) .

o Adequate provisions will be taken to prevent wind erosion and surface runoff from conveying pollutants from the waste material application disposal area onto the adjacent property.

Question 3:

As part of your environmental assessment, identify and discuss the potential alternatives to the proposed action. You state that the proposed action is requested, in part, because turbine building sumps become contaminated during .

operation with primary-to-secondary leakage, and that long-term operation with such leakage requires processing at a rate that would exceed the capacity of the Liquid Radwaste System (LRS). Accordingly, your discussion of alternatives should

• include (1) design changes to upgrade the capacity of the LRS, and (2) operational restrictions consistent with existing LRS capacity. Justify the proposed action in view of available alternatives.

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Response

1 Technical Specifications 3/4.11.1.5 allow small concentrations of radionuclides in the WC system. These may enter the system as a result of primary to secondary leaks and may be present as radionuclides which cannot be removed (e.g. tritium) and which will result in an insignificant increase in offsite dose. They may also be radionuclides which are at detectable concentrations, but cannot- be j~

further-reduced by tvailable plant processing equipment (ion exchange, filtration) and which will result in an insignificant increase in offsite dose commitment.

Examples include cesium-134 and 137 at less than 5E-07 microCi/ml.

Attempting to route this 100 gpm waste source to the 20 gpm radwaste system would result in reactor shutdown due to Turbine Building Hotwell Pit flooding. The proposed amendment would allow the release of WC system radioactivity at l concentrations within the current Tech Spec limit if the calculated offsite l concentrations and dose are within Tech Spec, 10 CFR 20, and 10 CFR 50 limits. As j such, there will be no change to the health and safety to the public.

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Alternatives examined included a) pumping the contents of a contaminated WC pond (2 million gallons) back to the Turbine Building for portable Ion Exchange process

.and then release to the CCW; b) Ion Exchange / Filtration of trace quantities of radionuclides in the 2 million gallon basin; and c) install increased LRS capacity.

None of these options will significantly affect offsite dose due to tritium. None of the options would significantly reduce instantaneous effluent concentrations for other nuclides.

Costs for the above options range from $250,000 for option a) to $8,000,000 for option c) for an offsite dose reduction of less than 0.3 mR/ year.

Question 4:

Identify any waste stream other than that of the Conventional Wastewater Treatment System that will also be released at the proposed alternate release point.

Discuss the measures taken to ensure adequate control of releases via any such other waste streams through this release point. Include sampling, analysis and monitoring provisions for any such waste stream.

Response

See Figure 1 '

Collection Basin (CB)

The Collection Basin receives treated sanitary effluent, yard drainage and

overflow from the Standby Nucler.r Service Water Pond. The overflow from the CB mixes with the discharge from the WC system in a concrece protected apron and is discharged to the Catawba River downstream of Cowans Ford Dam.

{ Outfall 003 Outfall 003 discharges treated sanitary waste from the Sanitary Waste Treatment System to the Collection Basin.

i Sanitary Waste Treatment System j

The Sanitary Waste Treatment System consists of an aerated-facultative lagoon system which is a trapezoidal multicellular arrangement consisting of a completely suspended cell followed by three partially suspended cells in series. The lagoon provides an approximate 5-day retention time and will allow for variable flow discharge. The wastewater effluent from the aerated lagoon flows through chlorinators, a chlorine contact chamber and a Parshall l Flume before discharging to the Collection Basin. Expansion space is provided should a sand filter be required in the future.

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The lagoon is lined with a flexible synthetic material such as hypalon, it is divided into four cells by a curtain material such as a polymer coated polyester with a weighted chain ballast and floatation collar. The first cell provides for a two day retention time and is kept in complete suspencion by surface mechanical aerators. The second and third cells are kept partially suspended providing for partial settling. Each of these two cells has a retention time of one day. The surface of this cell is kept slightly agitated to minimize algal growth. From the final cell, the wastewater discharges to a chlorination installation. After passing through the chlorinators, a retention time in excess of 30 minutes is provided by a contact chamber before being discharged to the Collection Basin.

The sewage lagoon has a multiple level discharge capability at 5, 6), and 8 feet. At each of these different levels of operation, the lagoon is able to provide a 5-day retention time for influent wastewater flow rates of 40,000 gpd, 52,000 gpd, and 64,000 gpd, respectively.

Sampling, analyses and monitoring programs to prevent unmonitored releases are discussed in response to Question le.

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INFLUENT INITIAL HOLDUP WT POND INFT.11ENT i

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4 WT LAGOON

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RIVER 1 WASTEWATER j COLLECTION BASIN i

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McGUIRE NUCLEAR STATION

) SOURCES OF EFFLUENT TO Tile CATAWBA RIVER

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