RA-05-011, Response to NRC Comments on Maine Yankee Area Classification Change: Storm Drains (D3500) - Section 7

Response to NRC Comments on Maine Yankee Area Classification Change: Storm Drains (D3500) - Section 7

ML050610436
Person / Time
Site:	Maine Yankee
Issue date:	02/23/2005
From:	Meisner M Maine Yankee Atomic Power Co
To:	Document Control Desk, NRC/FSME
References
MN-05-009, RA-05-011
Download: ML050610436 (5)

Text

Maine Yankee 321 OLD FERRY RD.

• WISCASSET, ME 04578-4922 February 23, 2005 MN-05-009 RA-05-011 UNITED STATES NUCLEAR REGULATORY COMMISSION Attention: Document Control Desk Washington, DC 20555

References:

(1) License No. DPR-36 (Docket No. 50-309)

(2) Maine Yankee Letter to the USNRC, MN-02-048, dated October 15, 2002, Revision 3, Maine Yankee's License Termination Plan (3) USNRC Letter to Maine Yankee, dated February 28, 2003, Issuance of Amendment No. 168 to Facility Operating License (4) USNRC Letter to Maine Yankee, dated August 23, 2002, "Maine Yankee Atomic Power Station re: License Termination Plan Issues" (5) Maine Yankee Letter to the NRC, MN-05-003, dated January 26, 2005 "Area Classification Change: Storm Drains (D3500) - Section 7" (6) USNRC Letter to Maine Yankee dated February 9, 2005, "Response to Area Classification Change: Storm Drains (D3500)"

Subject:

Response to NRC Comments on Maine Yankee Area Classification Change: Storm Drains (D3500) - Section 7 In a letter to the NRC, dated January 26, 2005 (Reference No. 5), Maine Yankee notified the NRC (per LTP section 1.4.1) of the change in area classification of a portion of storm drain piping Section 7 from Class 1 to Class 3.

License Termination Plan Section 5, Attachment 5A describes the embedded and buried pipe that will remain on site and identifies the classification and final status survey requirements for each pipe. In this LTP Attachment, storm drain piping sections 5 through 7 were classified as Class 1 buried pipe. This classification change applied to the portion of section 7 storm drain piping upstream of manhole 27 as shown on Figure 1 of Reference No. 5.

Maine Yankee applied the criteria specified in LTP section 5.6.4 to reduce this classification and notified the NRC accordingly. It was determined that this portion of section 7 storm drain piping meets the Class 3 requirements (per LTP Section 5.2.2), i.e.,

has a low probability of containing residual radioactivity. And that there is sufficient knowledge regarding the distribution of contamination within the reclassified Class 3 area to support a conclusion that the area has a low probability of containing residual radioactivity. In support of this determination, Maine Yankee examined the historical record and reviewed available soil survey data from the surrounding land areas that would be drained by this portion of the drain piping and reviewed available data from water samples routinely taken from the drain piping discharge outfall. The historical

U.S. Nuclear Regulatory Commission Attention: Document Control Desk Page 2 record did not identify any contamination events. The surrounding land areas had been previously surveyed under the FSS program and were found to meet the criteria of Class 3 land. The discharged water has typically been found to be less than MDA values with sporadic positive counts just above the MDA values. MDA's were maintained at approximately environmental LLD's associated with the Radiological Environmental Monitoring Program (REMP).

The NRC Staff responded with two comments in its letter to Maine Yankee, dated February 9, 2005 (Reference No. 6). For the record, Maine Yankee would like to clarify that the notification submitted in Reference No. 5 was not a request to reclassify this section of storm drain. It was a notification, provided 14 days prior to implementation in accordance with LTP Section 5.6.4 and Reference No. 4. However, in the interest of facilitating an efficient and timely NRC review of the drain piping survey documentation, scheduled to be submitted in FSS Report No. 9, Maine Yankee is providing the following information to address the NRC comments.

NRC Comment 1: Based on industry experience, water effluent samples may not be a good indicatorof residualradioactivityin a system, especially a passive system such as a storm drain or effluent piping. The staff recognizes the principalwater sourcefor the storm drain has been thefire protectionsystem and radiologicalcontamination is unlikely. Howvever, consistent with goodpractice, it is pnrdent to radiologically characterizesuch areasby obtainingsediment samples, loose surface and /or direct measurenments. Therefore, the request to re-classify this section of storm drainfrom Class I to Class 3 area should be based on ccharacterizationdatagatheredby characterization surveys since personnelaccess to the storm drain is achievable.

Maine Yankee Response Prior to receiving Reference No. 6, Maine Yankee recognized the need to obtain additional sediment and surface measurements. Maine Yankee excavated a portion of the storm drain pipe just north and upstream of Manhole 27. This section of pipe had the greatest potential for contamination from an interconnecting Class 1 pipe down stream of Manhole 27. Survey measurements were taken on this drain pipe. Thirty direct measurements (gross beta detectable) were taken on this drain pipe segment. The mean net measurement result was 1,340 dpm/lOOcm 2 and the maximum net measurement result was 2,305 dpm/100cm 2 compared with the buried pipe DCGL of 9,800 dpm/lOOcm 2 (see Attachment I - Table 1).

In addition, after excavating and removing the manholes in this portion of drain piping section 7, Maine Yankee took volumetric samples of soil directly underneath each manhole. These samples did not identify any residual activity (see Attachment I - Table 2).

U.S. Nuclear Regulatory Commission Attention: Document Control Desk Page 3 Thus, the change in classification of the storm drain is supported by measurements on the storm drain pipe itself and on soil directly under associated manholes following removal.

NRC Comment 2: In addition, please clarify how the storn drain areas will be segregatedand controlled with respect to separationof Class I and Class 3 areas.

Maine Yankee Response As shown in Maine Yankee's letter, MN-05-003 Figure 1, Manhole No. 27 is the connection point between Class 1 surface soil area (inside the RA) and the Class 3 surface soil area (outside the RA). These areas were serviced by the storm drain system when in place and functional. The portion of storm drain piping that is being reclassified serviced and is underneath a Class 3 area. At the 15.4 ft elevation, Manhole No. 27 was at a low point draining the upstream piping as high as the 17.9' elevation. The piping upstream of Manhole No. 27 has now been physically disconnected from the storm drain piping that serviced and was underneath the Class 1 soil area, i.e., inside the RA. The section of storm drain pipe in Section 7 immediately upstream of Manhole No. 27 was physically removed and used for characterization and FSS measurements. In addition, Manhole No. 27 has been removed. Maine Yankee is currently in the process of removing all the downstream storm drain piping underneath the RA. As such, there is no path of contamination from Class 1 areas through storm drain pipes to the remaining Section 7 pipe, which was reclassified to Class 3 Based upon the foregoing information, Maine Yankee believes that a reclassification of storm drain section 7 upstream of manhole 27 satisfies the applicable criteria of the License Termination Plan.

If you have any questions, please contact me.

Since 'ely, .'

Micha J. 4leisner Vice reent and Chief Nuclear Officer cc: Dr. R. R. Bellamy, NRC Region I Mr. C. Pray, State of Maine, Nuclear Safety Advisor Mr. P. J. Dostie, State of Maine, Division of Health Engineering Mr. D. Gillen, NRC Acting Director, Division of Waste Management Mr. S. J. Collins, NRC Regional Administrator, Region I Mr. J. Buckley, NRC NMSS Project Manager, Decommissioning Mr. M. Roberts, NRC Region I Mr. R. Shadis, Friends of the Coast

Attachment I Table 1 FD-3500 Storm Drain Section 7 Upstream of Manhole 27 Interior Pipe Surface Measur6ments Gross Net Direct Measurement cpm dpm/1 OOcm 2 dpm/1 OOcm 2 c001 445 3396 1107 C002 602 4594 2305 C003 481 3671 1381 C004 498 3800 1511 C005 501 3823 1534 C006 513 3915 1625 C007 451 3442 1152 COOB 494 3770 1480 C009 461 3518 1229 C010 408 3114 824 C011 532 4060 1770 C012 434 3312 1023 C013 441 3365 1076 C014 448 3419 1129 C015 472 3602 1313 C016 494 3770 1480 C017 454 3456 1175 C018 554 4228 1938 C019 511 3900 1610 C020 465 3549 1259 C021 426 3251 962 C022 449 3426 1137 C023 392 2991 702 C024 516 3938 1648 C025 496 3785 1496 C026 455 3472 1183 C027 441 3365 1076 C028 451 3442 1152 C029 494 3770 1480 C030 488 3724 1435 mean 3629 1340 median 3576 1286 std dev 334 333

Attachment I Table 2 FD-3500 Storm Drain Section 7 Upstream of Manhole 27 Excavated Manhole Sample Results Manhole pCi/g - Cs - 137 61 < 0.056 6M < 0.04 6L <0.04 6K < 0.04 6J < 0.04