ML082620092

Final Status Survey Summary Report, June 17, 2008, Stairwell 3 Rooms 116 and 210, Elevation 0- 0 to 20- 0, Auxiliary Building, Survey Unit F8131403

ML082620092
Person / Time
Site:	Rancho Seco
Issue date:	06/17/2008
From:	Stein M Sacramento Municipal Utility District (SMUD)
To:	NRC/FSME
References
MPC&D 08-064
Download: ML082620092 (20)

Text

I Rancho Seco Final Status Survey Summary Report June 17, 2008 Stairwell # 3 Rooms 116 and 210, Elevation 0'- 0" to 20'- 0", Auxiliary Building Survey Unit F8131403 Prepared By:

Date: 61/1'71,2M FSS Engineer Reviewed By:.-

• /*

4 Date: (a' 2S 106 Lead FSS Engineer Approved By:

7)/

Date:

7 2-0 Dismantlement Su intendent, Radiological

FINAL STATUS SURVEY

SUMMARY

REPORT Survey Unit:

F8131403, Stairwell # 3 Rooms 116 and 210, Elevation 0'- 0" to 20'- 0", Auxiliary Building Survey Unit

Description:

Operating History: Stairwell # 3 is located in what used to be considered the radiologically controlled section of the Auxiliary Building. The stairwell was assigned three room numbers as follows. Room # 116 is the section of the stairwell from elevation 0'- 0" (grade level) to elevation 10'- 0". Room # 210 is the section of the stairwell from elevation 10'- 0" to elevation 3 1'- 3". Room # 318 is the section of the stairwell from elevation 31'- 3" to elevation 52'- 0".

Site Characterization: Scan measurements for beta radiation were taken on the interior surfaces of Stairwell # 3. The measurements showed a mean gross activity level of 18,533 dpm/100 cm 2 and a maximum value of 192,616 dpm/l100 cm2 from grade level to elevation 20'- 0". The measurements showed a mean gross activity level of 4,595 dpm/100 cm 2 and a maximum value of 10,529 dpm/l00 cm 2 above elevation 20'- 0".

Based on the classification procedure (DSIP-0020) and levels of gross activity reported, the interior surfaces of Stairwell # 3, from grade level to elevation 20'- 0", were determined to be a Class 1 area and, above elevation 20'- 0", were determined to be a Class 2 area.

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 83 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 F8131403

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

F813 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 (m2):

Scan Area (M2):

Scan Coverage (%):

Sign P:

Calculated Relative Shift:

Relative Shift Used:

N-Value:

Design N-Value + 20%:

Design Min Samples N:

Grid Spacing L:

14031 83 Michael Stein 43000 3.9 167700 21500 6935 0.05 0.05 Cs-137 5.9 83 100%

1.645 1.645 0.99865 3.2 3

11 14 14 2.4 Stairwell # 3 Rooms 116 and 210, Elevation 0'- 0" to 20'- 0", Auxiliary Building Structure Surface LTP Table 5-4 Gross Activity DCGL Class 1 Class 1 Default = 50% DCGL Class 1 Class 1 Uses 3.0 if Relative Shift is

>3 NUREG-1575 Table 5-5 Class 1 Class I Page 3 of 8 FSS Summary Report F8131403

Survey Results:

A total of 14 direct measurements were made in F8131403. The results including mean, median, standard deviation and range are shown in Table 2. All direct measurements were less than the DCGL. One of the scan measurements (C0053BS) indicated an area of elevated activity. Scan activity ranged from 3,110 to 194,688 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 F8131403-CO001BD F8131403-CO002BD F8131403-CO003BD F8131403-CO004BD F8131403-CO005BD F8131403-CO006BD F8131403-CO007BD F8131403-CO008BD F8131403-CO009BD F8131403-CO01 OBD F8131403-CO011 BD F8131403-CO01 2BD F8131403-Co013BD F8131403-CO014BD Mean:

Median:

Standard Deviation:

Range:

3119 2844 3428 3439 10395 6856 3285 2976 3538 3439 3108 3362 3979 3197 4069 3395 2069 2844-10395 Page 4 of 8 FSS Summary Report F8131403

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

F8131403C0001SM 0.34 F8131403CO002SM

-0.95 F8131403C0003SM

-0.95 F8131403C0004SM

-0.95 F8131403C0005SM

-2.24 F8131403C0006SM 8.09 F8131403C0007SM

-4.82 F8131403C0008SM

-0.95 F8131403C0009SM

-2.24 F8131403C0010SM

-2.24 F8131403C0011SM 1.64 F8131403C0012SM 2.93 F8131403C0013SM

-2.24 F8131403C0014SM

-2.24 Mean:

-0.49 Median:

-0.95 Standard Deviation:

3.11 Range: 1

-4.82 to 8.09 Page 5 of 8 FSS Summary Report F8131403

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 FSS Summary Report F8131403

Table 4. Data Assessment Results Survey Results Parameter Value Comment Material Background Used (dpm/100 cm 2):

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

N/A Average Ambient BKG 0

Actual Direct Measurements (N):

14 Median (dpm/100 cm 2):

3395 Mean (dpm/100 cm2):

4069 Direct Measurement Standard Deviation 2069 (dpm/1.00 cm2):

Total Standard Deviation (dpm/100 cm 2):

2069 Based on samples and backgrounds.

Maximum (dpm/100 cm 2):

10395 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:

Yes Class 1 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 F8131403

Survey Unit Investigations and Results:

One investigation was required for the scan measurement C0053BS. The results are reported in Attachment 3. The EMC unity rule was not exceeded as shown in Table 3-1.

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. One potential area of elevated activity was detected and evaluated as shown in Attachment 3. Therefore, the EMC criterion was met.

==

Conclusion:==

The FSS of this survey unit was properly designed as a Class I 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 43,000 dpm/100 cm 2 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 is concluded that survey unit F813 1403 meets the release criteria of 10CFR20.1402.

Page 8 of 8 FSS Summary Report F8131403

Attachment I Maps June 17, 2008 Survey Unit F8131403

(b 0

9 PLAN Vi EEV., 0-0'd REELECTED CEIJUNG VIE ELEV 2b*

1 IELEV 1KG NORTH NORTH OF. M~ LNE 01 ELEV LKG EAS EkVS OF COL LINE, f

ELEV 1KG SOUTH At OtL UNE 9.7 ELEV LK WS WEST OF COL LINE ft 07 Lco 0 1SCALE 3

HLTER2 STAIR #3 ROOMS 116 & 21.0 FLOOR PLAN BETA DIRECT/LOOSE SURFACE ACTIVITY MEASUREMENT LOCATION F8131 403-M2 8 130o0o.04c SHEET.2 of 2 RO RA'h4C

(t~

(J3 0

ELEV. 0'-r R.EELECTED CEIUNG VIE ELEV. ZW-0' EL 20-0" ED L..ý W.-O*

ELEV 1KG NORTH NORTWO orCOL LINE 9.7 ELEV 1KG EAST E4SrOF COL LINE Ft ELEV LKG WEST WEST OF. 01 tiNE R

..DING.EL 20

.& 210 FLOOR PLAN 00 w

a.SURVEY!UMT CMtfNUES AROLWO4 A COMtER~

0 1

2 3

SCALE MCTERS SBETA SCAN MEASUREMENT LOCATIONS F51 31403-M I

00 C)~

0w e

PhLANYI:W ELEV. 0*-ýO' REFLECTED CEIUJNG VIEW aEu4. 20,-0b EL 2(--O' EL O-0 ELEVY LKG: NORTH NORM1 OF OOL UNE;9.3 ELEV LKG NORTH ELEV LKG EAST NOR'H OF, 00L UNE 9.5 EAST OF COL LWJ R AUXILIARY BUILDING EL 20 STAIR #3 ROOMS 116 & 210 FLO0 BETA SCAN MEASUREMENTS I

JUNCTURES WNIUPAL F8131403-M T

F81 31 403-M4 0:

1 2

3 ViETERS Instrumentation June 17, 2008 Survey Unit F8131403

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

Model; Serial No.

(dpm/100 cm2 )

(dpm/100 cm2 )

M2350; 180733 43-98B; 148638 1400 2520 M2350; 175834 43-68B; 190482 433 1033 M2350; 149789 43-116-1B; 256006 796 3258 M2350; 175834 43-116-1B; 190642 796 3258 Tennelec; 0401171 N/A 5.9 dpm P, N/A

___11.7 dpm [3 Table 2-2. Investigation Criteria and DCGL Value ParameterVau (dpm/100 cm 2)

Investigation Criteria - Direct 167700 Investigation Criteria - Scan 167700 DCGLw 43000 DCGLEMC 167700 Page 2 of 2 Att. 2 Instrumentation F8131403 Investigation June 17, 2008 Survey Unit F8131403

Table 3-1 Survey Unit Investigation Investigation Investigation DCGLemc Grid Investigation Initial Value Result Elevated Area DCGLemc Result Unity Level (cpm)

(cpm)

(cpm)

Area (i 2)

Factor (dpm/lOOcm2)

Fraction C0053BS 10,758 12,485 12,485

< 0.5 28.1 1,208,300 194,688 0.16 Survey Unit Remainder DCGL =

SU Mean =

43,000, 4,069 0.09 EMC Unity Sum 0.25 Page 2 of 2 Att. 3 Investigation F8131403 Data Assessment June 17, 2008 Survey Unit F8131403

CD t'7r Ua Ca 00 F8131403 Gross Activity Sample Results Quantile Plot DCGL = 43000 dpm/1 00cm2 12,000 10,000 I.

8,000 -

6,000 -

4,000 -

3395 2,000 0-0 20 40 60 80 100 Percentile Direct Measurements (dpm/100cm2) -

median -

- - 75th Percentile...

50th Percentile

C'D w

8131403 Gross Activity Sample Results Scatter Plot 41.DCGL=

43000 dpml1OOcm2 12000 S10000 a

a a a 6

a a a

10277 E 8000 6000 tz) 4000

,,,,,----,,,O*

4069

• a 0

0 0

00 00 A2000 En 0

-2000

-2130.........

8 8C to

.4

~a

~-V-Va W

0 0

0 1

a 0

a 0

C 0

U0 U U00 0

0 0

0U0 0

Measurement Locations 00.w-,

o-Gross Activity Average -

"+3StDev a

a "-3St7ev.

C:)

w

Ci2 cjn Wj F81 31403 Gross Activity Frequency Plot DCGL = 43000 dpmni1OOcm 2 C:

C 0

11 10 9

8 7

6 5

4 3

2 1

0 1~-

co 00 W*

Bins - Upper End Value (dpm/1 00cm2)