ML082620155

Final Status Survey Summary Report, June 30, 2008, East Heat Removal Cooler Room Between Columns 10.3 and 9.7, Room 051 Floor and Upper Walls and Ceiling Survey Unit F8130701

ML082620155
Person / Time
Site:	Rancho Seco
Issue date:	07/29/2008
From:	Stein M Sacramento Municipal Utility District (SMUD)
To:	NRC/FSME
References
MPC&D 08-064 F8130701
Download: ML082620155 (27)

Text

Rancho Seco Final Status Survey Summary Report June 30, 2008 East Heat Removal Cooler Room Between Columns 10.3 and 9.7, Room 051 Upper Walls and Ceiling Survey Unit F8130701 Prepared By: Date: i /20 SS Engineer Reviewed By.' oiJ f -J -I ate:-7 -3(C Lead FSS Engineer Approved By: 7 Date: 7" "1-Dismantlement Superintendent, Radiological

FINAL STATUS SURVEY

SUMMARY

'REPORT Survey Unit:

F8130701, East Heat Removal Cooler Room Between Columns 10.3 and 9.7, Room 051 Upper Walls and Ceiling Survey Unit

Description:

Operating History: The East Heat Removal Cooler Room is located on the -20' elevation of the Auxiliary Building. The Auxiliary Building is a reinforced concrete structure that, during power operations, contained the Radwaste processing and supporting systems.

The building has six main elevations. Residual levels of surface radioactivity were detected on all interior elevations of the building. Operating records and the HSA document several events with the potential for a release of radioactivity inside this structure.

Site Characterization: Direct measurements were taken on each interior elevation of the Auxiliary Building. These measurements confirmed the presence of plant-derived radionuclides. Direct measurements taken on the -20' elevation, showed a mean gross activity level of 247,831 dpm/100 cm2 and a maximum value of 10,080,000 dpm/100 cm 2 . Based on the classification procedure (DSIP-0020) and levels of gross activity reported, the interior surfaces of the Auxiliary Building were determined primarily to be a Class 1 for the floors and lower walls (bottom 2 meters of the walls), and Class 2 for the upper walls and ceiling. However, inside the East Heat Removal Cooler Room there were a number of areas on the upper walls and ceiling where the gross surface activity levels were higher than the DCGL prior to remediation. Therefore, a Class 1 final status survey was performed on the upper walls and ceiling of the East Heat Removal Cooler Room Between Columns 10.3 and 9.7, Room 051.

HSA Events: HSA Report pg. 63.

Survey Unit Design Information:

The Survey Unit Design Parameters are presented in Table 1 below. The survey unit and measurement locations are depicted on the maps in Attachment 1. Direct measurement locations were determined using a random-start, fixed grid pattern and 202 m2 were scanned for 100% coverage. Samples of removable contamination were collected at each direct measurement location. The instrumentation used for the survey along with the MDC values are listed in Tables 2-1 and 2-2 in Attachment 2.

Page 2 of 8 FSS Summary Report F 8130701

Table 1. Survey Unit Design Parameters Survey Design Value Comment Parameter Survey Area: F813 East Heat Removal Cooler Room Between Columns 10.3 and 9.7, Room 051 Upper Walls and Ceiling Survey Unit: 0701 Structure Surface Class: I LTP Table 5-4 SU Area (m2): 202 Evaluator: Michael Stein DCGL (dpm/1 00 cm'): 43000 Gross Activity DCGL Area Factor: 3.5 Class 1 Design DCGLemc 152301 Class 1 (dpm/100 cm 2):

LBGR (dpm/100 cm 2): 21500 Default = 50% DCGL Design Sigma (dpm/100 cm 2): 12035 Type I Error: 0.05 Type.11 Error: 0.05 Predominant Nuclide: Cs-137 Sample Area (m2): 7 Class 1 2 202 Scan Area (m ):

Scan Coverage (%): 100% Class 1 Zl.,  :

1.645 Zl.[P :

1.645 Sign P: 0.955435 Calculated Relative Shift: 1.7 Relative Shift Used: 1.7 Uses 3.0 if Relative Shift is

>3 N-Value: 14 Design N-Value + 20%: 17 NUREG- 1575 Table 5-5 Design Min Samples N: 29 Class 1 Grid Spacing L: 2.6 Class 1 Page 3 of 8 FSS Summary Report F8130701

Survey Results:

A total of 29 direct measurements were made in F8130701. The results including mean, median, standard deviation and range are shown in Table 2. All of the direct measurements except for COO1 7BD were less than the DCGL. None of the scan measurements indicated areas of elevated activity. Scan activity ranged from 2,167 to 137,563 dpm/100 cm 2, based on a surveyor efficiency of 0.5 and no background subtracted. Samples for removable surface activity were all less than 10% of the DCGL as shown in Table 3. Removable surface activity samples were counted for alpha activity and none was detected at the MDC shown in Table 2-1 of Attachment 2.

Table 2. Direct Measurement Results Measurement ID Gross Activity (dpm/100 cm)

F8130701-COOOIBD 1738 F8130701-CO002BD 1670 F8130701-CO003BD 1717 F8130701-C0004BD 1551 F8130701-CO005BD 1603 F8130701-CO006BD 1146 F8130701-CO007BD 1727 F8130701 -CO008BD 1852 F8130701-CO009BD 1644 F8130701--Co010 BD 1712 F8130701 -C0011IBD 1089 F8130701-CO012BD 1286 F8130701-CO013BD 1795 F8130701-CO014BD 1743 F8130701-Co015BD 1644 F8130701-CO016BD 986 F8130701-CO017BD 47614 F8130701-CO018BD 1546 F8130701-CO019BD 1349 F8130701-CO02OBD 1385 F8130701 -C0021 BD 1318 F8130701-CO022BD 970 F8130701-CO023BD 954 F8130701-CO024BD 1675 F8130701-CO025BD 2168 F8130701-CO026BD 7807 F8130701-CO027BD 1509 F8130701-CO028BD 1743 F8130701 -CO029BD 1904 Mean: 3340 Median: 1644 Standard Deviation: 8600 Ran qe: 954-47614 Ranqe: 954-47614 Page 4 of 8 FSS Summary Report F8130701

Table 3. Removable Surface Activity Results Measurement ID Surface Beta Activity (dpm/100 cm 2 )

F8130701CO000ISM 5.51 F8130701 C0002SM 1.64 F8130701 C0003SM 1.64 F8130701 C0004SM 2.93 F8130701CO005SM -0.95 F8130701C0006SM 4.22 F8130701 C0007SM -0.95 F8130701CO008SM 0.34 F8130701 C0009SM -0.95 F8130701Co010SM 0.34 F8130701C0011SM 18.42 F8130701Co012SM 2.93 F8130701Co013SM 2.93 F8130701 C0014SM 1.64 F8130701CO015SM 4.22 F8130701CO016SM 4.22 F8130701CO017SM 232.8 F8130701C0018SM -0.95 F8130701Co019SM -3.53 F8130701CO020SM 9.38 F8130701 C0021 SM -0.95 F8130701 C0022SM 2.93 F8130701CO023SM -0.95 F8130701C0024SM 6.8 F8130701C0025SM 21.01 F8130701C0026SM 206.98 F8130701C0027SM 4.22 F8130701C0028SM 5.51 F8130701C0029SM 104.95 Mean: .21.94 Median: 2.93 Standard Deviation: 58.31 Range: -3.53 to 232.8 Page 5 of 8 FSS Summary Report F8130701

Survey Unit Data Assessment:

The survey design required 29 direct measurements for the Sign Test. The critical value and the results of the Sign Test are presented in Table 4. The sample mean and median values were less than the DCGL. The sample standard deviation was less than the design standard deviation so no additional samples were required.

Page 6 of 8 FSS Summary Report F8130701

Table 4. Data Assessment Results Survey Results Parameter Value Comment Material Background Used (dpm/100 cm 2 ): N/A Ambient Background Used (dpm/IO0 cm 2 ): N/A Average Ambient BKG = 0 Actual Direct Measurements (N): 29 Median (dpm/100 cm 2 ): 1644 Mean (dpm/100 2 cm ): 3340 Direct Measurement Standard Deviation 8600 (dpm/100 cm 2 ):

Total Standard Deviation (dpm/100 cm 2 ): 8600 Based on samples and backgrounds.

Maximum (dpm/100 2 cm ): 47614 Material Type: N/A Background Subtract Not Applied Sign Test Final N Value: 29 S+ Value: 28 Critical Value: 19 Sufficient Samples Collected: Yes Maximum Value < DCGL: Investigate Small Area < 1 m 2, Activity 47,614 dpm/100cm 2 Median Value < DCGL: Yes Mean Value < DCGL: Yes Maximum Value < DCGLemc: Yes Class 1 Total Standard Deviation <= Sigma: Yes Pass the Sign Test? Yes Reject the Null Hypothesis? Investigate Yes, Passed Sign Test Does the Survey Unit Pass All Criteria? Investigate Yes Page 7 of 8 FSS Summary Report F8130701

Survey Unit Investigations and Results:

No investigations were required for either direct or scan measurements and no investigation results are reported.

ALARA Statement:

As stated in Chapter 4 of the LTP, as long as the residual activity within the survey unit is less than the DCGL (i.e. the survey unit average activity is less than the DCGL and the EMC criterion has been met), the ALARA criterion has been met.

Changes in Initial Survey Unit Assumptions:

The survey unit was designed as a Class 1 structure survey and the sample results are consistent with that classification. The variability of the survey results was less than the characterization data used for survey design. No potential areas of elevated activity were detected.

==

Conclusion:==

The FSS of this survey unit was properly designed as a Class 1 survey based on Table 5-4 of the LTP. The required number of direct measurements was made and the scan coverage met the requirement of Table 5-6 of the LTP. All of the direct measurements except for COO17BD were less than the DCGL of 43000 dpm/100 cm 2 . None of the removable surface activity measurements exceeded 10% of the DCGL. No investigations were required.

The direct measurement data support rejection of the null hypothesis, providing high confidence that the survey unit satisfied the release criteria and that the data quality objectives were met.

It is concluded that survey unit F8130701 meets the release criteria of 10CFR20.1402.

Page 8 of 8 FSS Summary Report F8130701

Attachment 1 Maps June 30, 2008 Survey Unit F8130701

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-w Walls 86.9 m22 0 Cable Chase. 32.8 m Scale Meters ROOM 51 SECTION 1 CEILING 2

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Attachment 2 Instrumentation June 30, 2008 Survey Unit F8130701

Table 2-1. Survey Unit Instrumentation Instrument Detector MDC Static MDC Scan Model; Serial No. Model; Serial No. (dpm/100 cmM) (dpm/100 cm 2 )

M2350; 142514 43-98B; 148639 550 990 M2350; 193700 43-68B; 190294 433 1033 M2350; 149789 43-68B; 161397 433 1033 M2350; 203481 43-68B; 148629 433 1033 M2350; 149789 43-116-1B; 256006 491 13Juncture 739 13Juncture M2350; 193700 43-116-1B; 216072 796 3258 Tennelec; 0401171 N/A 5.9 dpm a' N/A 11.7 dpm __

The scan and static MDC's provided represent the most conservative MDC values for the survey conducted.

Table 2-2. Investigation Criteria and DCGL Value Parameter (dpm/100 cm 2)

Investigation Criteria - Direct 150500 Investigation Criteria - Scan 150500 DCGLw 43000 DCGLEMc 150500 Page 2 -of2 Att. 2 Instrumentation F8130701

Attachment 3 Investigation June 30, 2008 Survey Unit F8130701 (none required)

Attachment 4 Data Assessment June 30, 2008 Survey Unit F8130701

CF8130701 Gross Activity Sample Results Quantile Plot DCGL = 43000 dpm/1 00cm2 50,000 z 45,000 40,000 - -

35,000 30,000 ?X * * "

25,000 -

20,000 -

5,000 0

1644 0 20 40 60 80 100 Percentile

• Direct Measurements (dpmIl0Ocm2) - median -75th Percentile ---- 50th Percentile w0-C)

F830701 Gross Activity Sample Results Scatter Plot F

DCGL 43000 dpmll00cmR 60000 50000 E 40000

> 30000 . . . . . . . . . . .. ..-- - - - - - - - 2913E E20000

'a 0

~-10000 CD I I I . I I I I I

-20000 - -- - - 2 oocoooooooooooooa^ ocoo ooc acoCC00000000000000COOOOC30 0000 Measurement Locations 00 w o Gross Activity - Average - - "+3StDev" - - "-3StDev" 0 I.tI Il ll L II III

F8130701 Gross Activity Frequency Plot C

DCGL = 43000 dpm/1 00cm2 28 24 ~ <

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