ML073400097
| ML073400097 | |
| Person / Time | |
|---|---|
| Site: | Plum Brook |
| Issue date: | 11/29/2007 |
| From: | Randall D, Wood G US National Aeronautics & Space Admin (NASA) |
| To: | NRC/RGN-III/DNMS/DB |
| References | |
| EP-RX-138-2 | |
| Download: ML073400097 (16) | |
Text
Survey Unit Release Record 1 Design # I EP-Rx 138-2 / Revision W I Original 1 Page I of 4 1 Suwey Unit #(s) Rx 138-2
- 1) Embedded Pipe (EP) Survey Unit Rx 138-2 meets the definition of embedded pipe for Plum Brook Reactor Facility (PBRF).
- 2) EP Rx 138-2 is a Class 1, Group 1 survey unit as per the PBRF Final Status Survey Plan (FSSP) and Technical Basis Document (TBD)-06-004.
- 3) Surveys in EP Rx 138-2 were performed using a scintillation detector optimized to measure gamma energies representative of Co-60. Sample #EP 3-9 from Survey Request (SR)-13 was referenced for this decision.
- 4) Survey Instructions for this survey unit are incorporated into and performed in accordance with (IAW) the Babcock Services Incorporated (BSI)/LVS-002, Work Execution Package (WEP)05-006. Survey instructions described in this Description document constitute "Special Methods" and the survey design used in the acquisition of survey measurements.
- 5) Instrument efficiency determinations are developed in accordance with the BSIILVS-002, WEP 05-006, these determinations are appropriate for the types of radiation involved and the media being surveyed.
- 6) Only the eight feet of the approximate overall length of twenty two feet of this pipe was accessible for final survey. However, it is concluded that the final survey of the accessible portion of this pipe system is appropriate to demonstrate the radiological condition of the entire pipe and the suitability of the pipe for unrestricted release.
Approval Signatures Date:
FSSICharacterization Engineer FSSICharacterization Manager
FSS Design # EP Rx 138-2 Revision # Original Page 2 of 4 Survey Unit: Rx 138-2 1.0 History/Description 1.1 The subject pipe system is a 1 system line. The ends of the piping section are accessible from the Sub Pile Room and Quad D on the -25 elevation of the Reactor Building.
1.2 EP Rx 138-2 is approximately 22 feet in length. The middle portion of the pipe run could not be accessed for survey due to a series of mitered, 90o elbows that prevent the travel of radiological detectors past the access points. Consequently, only eight of the approximate 22 feet of total length for this pipe was accessible for survey.
2.0 Survey Design Information 2.1 EP Rx 138-2 was surveyed IAW Procedure #BSI/LVS-002.
2.2 The accessible portion of the 1 ID pipe was surveyed by static measurement at one foot increments, for a total of 8 survey measurements.
2.3 Surface area for the 1 ID piping is 243 cm2 for each foot of piping, corresponding to a total 1 ID piping surface area of 1,946 cm2 (0.2 m2) for the entire accessible length of (8) of 1 piping.
3.0 Survey Unit Measurement Locations/Data 3.1 Pipe interior radiological survey forms are provided in Attachment 2 of this release record.
4.0 Survey Unit Investigations/Results 4.1 None 5.0 Data Assessment Results 5.1 Data assessment results are provided in the EP/Buried Pipe (BP) Survey Report provided in Attachment 1.
5.2 Only the eight feet of the approximate overall length of 22 feet of this pipe was accessible for final survey.
5.3 All measurement results from the eight feet of accessible pipe are less than the Derived Concentration Guideline Level (DCGL) for radionuclide specific EP that corresponds to the 1 mrem/yr dose goal established in Table 3-3 of the FSSP.
5.4 Background was not subtracted from the survey measurements and the Elevated Measurement Comparison (EMC) was not employed for the accessible portion of this survey unit.
5.5 In addition to the eight final survey measurements taken in the accessible portion of this pipe, additional radiological surveys were performed to the extent possible as allowed by the configuration of this piping. These surveys were performed to provide additional assurance that the
FSS Design # EP Rx 138-2 Revision # Original Page 3 of 4 Survey Unit: Rx 138-2 radiological conditions represented by the eight interior survey measurements are representative of the entire length of pipe.
5.6 Scan surveys were performed for pre and post remediation purposes, using a beta-gamma GM detector on the exterior of the access point for this pipe system. The surveys are documented as survey nos. NASA-07-3204 and NASA-07-3221, performed in support of RWP PB-07-100. Both pre and post surveys showed negligible levels of activity. The scan survey results indicated activity <1,000 dpm per direct frisk. In addition, smear rag was pulled through the length of the piping section. No loose radiological contamination greater than 1,000 dpm/100cm2 was detected.
5.7 Based upon the results of the final survey measurements combined with the results of the operational survey, it is reasonable to conclude that the final survey of the accessible portion of this pipe system is appropriate to demonstrate the radiological condition of the entire pipe. Survey Unit EP Rx 138-2 demonstrates compliance with the DCGL values, as presented in Sections 3.3, 7.5 and Attachment C of the PBRF FSSP.
5.8 When implementing the Unity Rule, provided in Section 3.6.3 of the FSSP, and applying the Nuclide Fraction (NF), provided in TBD-06-004, the survey unit that is constituted by EP Rx 138-2 passes FSS.
Statistical Summary Table Statistical Parameter 1 Pipe Total Number of Survey Measurements 8 Number of Measurements >MDC 8 Number of Measurements Above 50% of DCGL 0 Number of Measurements Above DCGL 0 Mean 0.0855 Median 0.0794 Standard Deviation 0.0203 Maximum 0.1174 Minimum 0.0587 6.0 Documentation of evaluations pertaining to compliance with the unrestricted use limit of 25 mrem/yr and dose contributions from Embedded Pipe and radionuclides contributing 10% in aggregate of the total dose for both structural scenarios and soils.
FSS Design # EP Rx 138-2 Revision # Original Page 4 of 4 Survey Unit: Rx 138-2 6.1 A review of the survey results has shown that the dose contribution for the accessible portion of EP Rx 138-2 to be less than 1 mrem/yr. The dose contribution is estimated to be 0.086 mrem/yr based on the average of the actual gross counts.
7.0 Attachments Attachment 1 - BSI EP/BP Survey Report Attachment 2 -Pipe Interior Radiological Survey Form & Radiation Protection Survey Forms Attachment 3 - DQA Worksheet Attachment 4 -Disc containing RR for EP Rx 138-2 & Spreadsheet
SECTION 7 ATTACHMENT 1 2 PAGE(S)
BSI EPlBP SURVEY REPORT Survey Location DatectorSled #
Detector Efficiency UES NOT BACKGROUND CORRECTED RP Engineer I Date
EP Rx 138-2 1" Pipe TBD 06-004 Group 1 Measurement #
Co-60 activity Co-60 activity Cs-137 activity Eu-152 activity Eu-154 activity Nb-94 activity Ag-108m activity gcpm ncpm (total dpm) (dpm/100cm2) (dpm/100cm2) (dpm/100cm2) (dpm/100cm2) (dpm/100cm2) (dpm/100cm2)
Unity 1 20 20 28,169 11,582 459 10,986 2,921 338 81 0.069 2 24 24 33,803 13,898 551 13,184 3,505 406 97 0.083 3 22 22 30,986 12,740 505 12,085 3,213 372 89 0.076 4 34 34 47,887 19,689 780 18,677 4,965 575 137 0.117 5 32 32 45,070 18,531 734 17,578 4,673 541 129 0.111 6 22 22 30,986 12,740 505 12,085 3,213 372 89 0.076 7 27 27 38,028 15,635 620 14,832 3,943 456 109 0.093 8 17 17 23,944 9,844 390 9,339 2,483 287 69 0.059 MEAN 0.085 MEDIAN 0.079 STD DEV 0.020 MAX 0.117 MIN 0.059 1 of 1
SECTION 7 ATTACHMENT 2 s PAGE(S)
BSVLVSPipeCra~fler-002 Revision 5 Pipe InteTior Radiplogical Survey Form Date: 11 3-7. 07 Tune: /+!a 4 QuM 'I 0
Pipe ID#:
Buifdin&:
R X 132 A' PipeDiameter:
Elevation; - I Access Point Area:
System' 4: .%G( Qrn~n Type of Survey Investigation Characterization -Final S w e y Other J Gross Co60J Cs Detector m I SM ID# Pmr FD 1 .S L-X/ DWI A/A Detectm Cal Date: 9.l r - \ . U I Detector Cal Due Date: 9 . 13 08
~nstrument: ~%o-I Instrument lD #: W Y 68 Instrument Cal Date: 9.14:~7 Instrument Cal Due Date: ' 7 . /Cf . DF From the Daily pipe Survey Detector .ContmlForm for the selected Detector BackgoundValue 7.b cpm MDCRstatiti, la. la^ . C P ~
Eficiency.Factar W i p e Diameter . 0.00 07 1 (from detector efficiwcy d e t e d t i o n )
Is the MDCt,h, acceptable? NO (if no, adjust sample count time and recalculate M D C b J 5 -
I 5 &w. Q~l3 d bD". &iAw 8-io M.
Technician Signature . ~ . . ..
/ \
Pipe Interior hdioiogiea1 Suwey V
Package Page 1 of 3.
Attachment 3, Page 1 ,
RADIATION PROTECTION SURVEY BORM
RADIATION FROTEGTlON SURVEY FORM SECTION 7 ATTACHMENT 3 1 PAGE(S)
- 4. Was the instrumentation MDC for stmcture scan measurements, soil scan measurements and FSSICharaderization Engineer (prinvsign)
FSSl Characterizstion Manager (prinwsign) cs-0912 Page I of 1
SECTION 7 ATTACHMENT 4 1 DISC