ML081610249

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Final Status Survey Summary Report March 24, 2008 Intake Pump Structure Survey, Unit F8230001
ML081610249
Person / Time
Site: Rancho Seco
Issue date: 03/24/2008
From:
Sacramento Municipal Utility District (SMUD)
To:
NRC/FSME
References
MPC&D 08-032
Download: ML081610249 (25)
v • d • e


Text

Rancho Seco Final Status Survey Summary Report March 24, 2008 Intake Pump Structure Survey Unit F8230001 Prepared By: *

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Date:__________

Reviewed By:

Date: _________

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-rLe-ad/S'*'S Engineer Approved By:

Date:

Dismantlement Superintendent, Radiological

FINAL STATUS SURVEY

SUMMARY

REPORT Survey Unit:

F8230001, Intake Pump Structure Survey Unit

Description:

Operating History: This structure, located south of the cooling towers, housed the pumps which delivered cooling water to the cooling towers. This area was not reported to have been used for the storage of radioactive material. Operating records and the HSA document no events with the potential for a release of radioactivity. associated with this

.survey area.

Site Characterization: Direct measurements were made of the surfaces of the structure which confirmed the absence of plant-derived radionuclides. Direct measurements showed a mean gross activity level of 260 dpm/100 cm2 and a maximum value of 1,375 dpm/100 cm2. Based on the classification procedure (DSIP-0020) and levels of gross activity reported, the area was determined to be a Class 3 area.

HSA Events: None 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 randomly determined and 21 m2 were scanned for approximately 5%

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 F823000i

Table 1. Survey Unit Design Parameters Survey Design Value Comment Parameter Survey Area:

Survey Unit:

Class:

SU Area (m2):

Evaluator:

DCGL (dpm/100 cm 2):

Area Factor:

Design DCGLemc (dpm/100 cm 2):

LBGR (dpm/100 cm 2):

Design Sigma (dpm/100 cm 2):

Type I Error:

Type II Error:

Predominant Nuclide:

Sample Area (m):

Scan Area (M2):

Scan Coverage (%):

Z1,* :

Sign P:

Calculated Relative Shift:

Relative Shift Used:

N-Value:

Design N-Value + 20%:

Design Min Samples N:

Grid Spacing L:

F823 0001 3

402 Erin L. Brown 43000 N/A N/A 21500 667 0.05 0.05 Cs-137 N/A 21 5%

1.645 1.645 0.99865 32.2 3

11 14 14 N/A Intake Pump Structure Structure Surface LTP Table 5-4 Gross Activity DCGL Class 3 Class 3 Default = 50% DCGL Class 3 Class 3 Uses 3.0 if Relative Shift is

>3 NUREG-1575 Table 5-5 Class 3 Class 3 Page 3 of 8 FSS Summary Report F8230001

Survey Results:

A total of 14 direct measurements were made in F8230001. The results including mean, median, standard deviation and range are shown in Table 2. All direct measurements were less than the DCGL. None of the scan measurements indicated areas of elevated activity. Scan activity ranged from 4013 to 6896 dpmr/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 Activit (dpm/100 cm F8230001-CO001BD F8230001-CO002BD F8230001-CO003BD F8230001 -CO004BD F8230001-CO005BD F8230001-CO006BD F8230001-CO007BD F8230001-COO08BD F8230001 -Co009BD F8230001-COOOBD F8230001-CO011BD F8230001-CO012BD F8230001 -CO01 3.BD F8230001-CO014BD

. Mean:

Median:

Standard Deviation:

Range:

2314 2282 2469 2256 2350 2443 1810 1790 2298 2371 2630 1935 2469 2552 2284 2332 262 1790-2630

.Page 4 of 8 FSS Summary Report F8230001

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

F8230001 C0001 SM

-2.24 F8230001C0002SM

-2.24 F8230001CO003SM

-3.53 F8230001 C0004SM

-3.53 F8230001 C0005SM

-2.24 F8230001CO006SM

-0.95 F8230001 C0007SM 1.64 F8230001 C0008SM

-3.53 F8230001C0009SM

-4.82 F8230001CO010SM

-4.82 F8230001CO01ISM 1.64 F8230001C0012SM 1.64 F8230001C0013SM 0.34 F8230001C0014SM 1.64 Mean:

-1.5 Median:

-2.24 Standard Deviation:

2.47 Range:

-4.82 to 1.64 Page 5 of 8 FSS Summary Report F8230001

Survey Unit Data Assessment:

The survey design required 14 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 Page 6 of 8 FSS Summary Report F200 F8230001

Table 4. Data Assessment Results, Survey Results Parameter Value Comment Material Background Used (dpm/100 cm2):

N/A Ambient Background Used (dpm/100 cm2):

N/A Average Ambient BKG = 0 Actual Direct Measurements (N):

14 Median (dpm/100 cm2):

2332 Mean (dpm/100 cm 2):

2284 Direct Measurement Standard Deviation 262 (dpm/100 cm2):

Total Standard Deviation (dpm/100 cm 2):.

262 Based on samples and backgrounds.

Maximum (dpm/100 cm2):

2630 Material Type:

N/A Background Subtract Not Applied Sign Test Final N Value:

14 S+ Value:

14 Critical Value:

10 Sufficient Samples Collected:

Yes Maximum Value < DCGL:

Yes Median Value < DCGL:

Yes Mean Value < DCGL:

Yes Maximum Value < DCGLemc:

N/A Class 3 Total Standard Deviation <= Sigma:

Yes Pass the Sign Test?

Yes Reject the Null Hypothesis?

Yes Does the Survey Unit Pass All Criteria?

Yes Page 7 of 8 FSS Summary Report F8230001

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), the ALARA criterion has been met.

Changes in Initial Survey Unit Assumptions:

The survey unit was designed as a Class 3 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 3 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. No direct measurements exceeded the DCGL of 43000 dpm/100 cm2 and 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 isconcluded that survey unit F8230001 meets the release criteria of 10CFR20.1402.

Page 8 of 8 FSS Summary Report F8230001 Maps March 24, 2008 Survey Unit F8230001

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- OF 3 RC F.VMOND SCALE METERS Instrumentation March 24, 2008 Survey Unit F8230001

Table 2-1. Survey Unit Instrumentation Instrument Detector MDC Static MDC Scan Model; Serial No.

Model; Serial No.

(dpm/100 cm')

(dpm/100 cm2 )

M2350; 193715 43-68B; 160703 433 1033 Tennelec; 0401171 N/A 5.9 dpmn a, 11.7 N/A dpm Table 2-2. Investigation Criteria and DCGL Value Parameter (dpm/100 cm2)

Investigation Criteria - Direct 21500 Investigation Criteria - Scan 43000 DCGLw 43000 DCGLEMC N/A Page 2 of 2 Att. 2 Instrumentation F8230001 Investigation March 24, 2008 Survey Unit F8230001 (none required)

Data Assessment March 24, 2008 Survey Unit F8230001

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