ML042860355

YA-REPT-00-002-04, Evaluation of Effluent Releases from Onsite Incineration of Waste.

ML042860355
Person / Time
Site:	Yankee Rowe
Issue date:	04/13/2004
From:	Yates A Yankee Atomic Electric Co
To:	NRC/FSME
References
-RFPFR YA-REPT-00-002-04
Download: ML042860355 (5)

Text

COPY TECHNICAL REPORT TITLE PAGE Evaluation of Effluent Releases from Onsite Incineration of Waste Title YA-REPT-00-002-04 Technical Report Number Approvals (Print & Sign Name)

Preparer Allen Yates L. y06 Date: f ')

Reviewer Date:

Approver (Cognizant Manager): Date:

/5 ;

TECHNICAL REPORT TITLE PAGE Evaluation of Effluent Releases from Onsite Incinerator Waste Title YA-REPT-00-002-04 Technical Report Number Approvals (Print & Sign Name)

Preparer. Date:

Reviewer: fRob a- L.. m i,, Date: /4_0o I --

Approver (Cognizant Manager) -- 4^6 _ .

Date: S-/ 'Z-lf t5UtJ Aut~f I

PURPOSE Condition Report (CR)03-647 was written to document the discovery that incinerator releases between early 1964 and 1975 were not included or evaluated in Calculation YRC- 178, "Radionuclide Soil Concentration Surrounding YNPS from Gaseous Release During Plant Operation," dated March 1998. This report evaluates those additional releases of particulate matter from the radioactive material incinerator at Yankee Nuclear Power Station (YNPS) and their effect on radionuclide soil concentrations surrounding YNPS in order to respond to the CR.

BACKGROUND In support of the Yankee Nuclear Power Station decommissioning, a vendor was contracted to calculate the maximum soil concentrations of radionuclides deposited offsite from historical gaseous effluent releases. YRC-1 178, "Radionuclide Soil Concentrations Surrounding YNPS Resulting from Gaseous Releases during Plant Operation" was completed in March of 1998. The calculation, performed by the vendor, assumed all releases were from the Plant Stack, as an elevated mix-mode release.

The report stated that the onsite radioactive material incinerator was shutdown in February of 1964 (pending a review of elevated activity detected on the discharge filter).

Furthermore, the report assumed that the incinerator was not returned to operation and if it had been, the released activity would be minor in relation to the total gaseous effluent activity used in the calculation.

In December 2003, during an ongoing review of information being utilized to support the License Termination Plan, it was recognized that the radioactive material incinerator had operated up until approximately 1976 (File number OEG 146/76, "Use of Incinerator at Yankee Rowe" from J.L. French to R.G. Randall). Since YRC-1 178 had not included the releases from the incinerator, a CR was written, and it was determined that a Technical Report would be produced in order to ensure the assumption for incinerator operation stated in YRC-1 178 was valid.

DISCUSSION The incinerator operation resulted in radioactive effluent ground-level releases, where the release point for incinerator was at a significantly lower height than the elevated mixed-mode releases from the Plant Vent Stack (PVS). Memorandum REG 98-001, "Dose Calculations for Ground Level Tritium and Particulate Releases at YNPS", dated January 2, 1998, discusses the issue of elevated mixed-mode deposition factors (D/Q) compared to the ground level deposition factors. It found that the elevated mixed mode D/Q was actually greater than the D/Q calculated for ground level releases. This was due to the environmental conditions surrounding the location of the nuclear plant. Therefore, the elevated mixed mode D/Q utilized in YRC-I 178 (8.79E-08 I/m 2 ) can be used to evaluate the activity released from the incinerator and provide a conservative estimate

pertaining to surface and soil deposition. The equation that identifies the anticipated radionculide concentration in pCi/g from such deposition is:

pCilg = Curies x (D/Q in m 2)X (lxl O2 pCi/Ci)/[2.40x10 5 g of soil per M2 ]

where:

2.40x10 5 g of soil per m2 is soil areal density identified in R.G. 1.109, Table E-15 D/Q value and the deposition equation are as derived in YRC-1 178 The following table shows the estimated contribution to soil and surface activity as a result of particulate activity released during incinerator operations at YNPS. The calculations are performed in accordance with YRC-I 178, except the total Beta-Gamma activity released during the year is not decay corrected to 1998. Decay correction was not performed since the isotopic mix of radionuclides is unknown. Thus, the values for the activity released by the incinerator discharge are overestimated.

[YRC-1 178 used the distribution of radionuclides estimated from the EPA Report "RD-7 1-1 Radiological Surveillance Studies at a Pressurized Water Nuclear Power Reactor" (1971), applied this distribution to the reported activity form the PVS release and then individually decayed each radionuclide according to its own half-life.]

Soil Soil Total Incinerator Concentration Concentration From Incinerator From PVS Activity Surface Releases Released Concentration Releases pCi/g Year (Ci) DIQ pCi/m 2 pCI/g 61- 8.96E-05 8.79E-08 7.88E+OO 3.28E-05 6.95E-04 62 2.01 E-08 8.79E-08 1.77E-03 7.37E-09 7.95E+00 63- 8.96E-05 8.79E-08 7.88E+00 3.28E-05 2.86E+00 64 1.66E-07 8.79E-08 1.46E-02 6.1 OE-09 3.96E-01 65 8.96E-05 8.79E-08 7.88E+00 3.28E-05 1.84E-04 66 2.29E-05 8.79E-08 2.01 E+00 8.39E-06 3.39E-04 67 8.96E-05 8.79E-08 7.88E+00 3.28E-05 3.30E-04 68 4.84E-06 8.79E-08 4.25E-01 1.77E-06 9.20E-05 69 2.80E-06 8.79E-08 2.46E-01 1.03E-06 5.90E-04 70 1.82E-06 8.79E-08 1.60E-01 6.67E-07 2.36E-03 71 1.08E-06 8.79E-08 9.49E-02 3.96E-07 1.76E-03 72- 8.96E-05 8.79E-08 7.88E+00 3.28E-05 5.32E-04 73- 8.96E-05 8.79E-08 7.88E+00 3.28E-05 9.26E-04 74- 8.96E-05 8.79E-08 7.88E+O0 3.28E-05 1.13E-02 75- 8.96E-05 8.79E-08 7.88E+00 3.28E-05 2.19E-02 76- 8.96E-05 8.79E-08 7.88E+00 3.28E-05 4.78E-05

• The releases occurring during these years are estimates based on the activity released during 1965 the year for which the highest release was recorded.

In a letter dated February 10, 1965 (YA-2229) from J.W. Bernsee (Health Physics) to David C. Costello (US AEC) states that there were 64 batches burned in the incinerator in 1964. The discharge activity of the incinerator was recorded on a log sheet titled

"Yankee Atomic Electric Company-Beta Gamma Air Sample Record." Eiqht of these records were located. The average value for these discharges was 2.59xl0 microcuries.

If this value is multiplied by 64, the total activity of all discharges is 1.66xl1O' microcuries. The frequency of these incinerator batches was principally due to a long refueling outage that year.

During 1962 it appears from the records located that incinerator operation was monthly.

The value derived for 1962 is from those records.

Comparison of the soil concentrations from the incinerator discharge with the PVS discharge shows that the incinerator contributed negligibly over the years that it operated.

The observed concentrations for soil only due to PVS releases are significantly below normal detection levels (-0.05 pCi/g assuming all the activity was due only to a radionuclide such as 137CS). These values are also a factor of 20 less than the analytical value for only 137Cs for the surface soil surrounding the YNPS site (of approximately 0.9 pCig from YRC-1 180). The value of 0.9 pCi 7 Cs per gram of soil is the median environmental background deposition due to atmospheric testing (see NCRP 50). Thus the concentration in soil of a potential marker of plant activity, 'Cs, is the same as would be expected from atmospheric deposition due to atmospheric testing.

CONCLUSION The estimated values of activity, which could have been deposited, based on site-specific meteorological models are well below the current analytic detection capabilities. The assumption that the incinerator operation contributed negligibly to the atmospheric deposition resulting from PVS releases is still valid.