ML051330139
| ML051330139 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 03/30/2005 |
| From: | Adams W Oak Ridge Institute for Science & Education |
| To: | John Hickman NRC/NMSS/DWM |
| References | |
| RFTA 04-007 | |
| Download: ML051330139 (7) | |
Text
O R I S E O A K R I D G E I N S T I T U T E F O R S C I E N C E A N D E D U C A T I O N March 30,2005 Mr. John Hickman Mail Stop: 7F27 Division of Waste Management U.S. Nuclear Regulatory Commission Two White Flint North 1 1545 Rockville Pike Rockville, h4D 20852-2738
-* c3
SUBJECT:
FINAL LETTER REPORT-IN-PROCESS INSPECTION SURVE@
RESULTS FOR THE REACTOR SUPPORT STRUCTURE, YAN@E NUCLEAR POWER STATION, R O W, MASSACHUSETTS [DOCKET NO. 50-29; RFTA NO. 04-0071
Dear Mr. Hickman:
The Environmental Survey and Site Assessment Program (ESSAP) of the Oak Ridge Institute for Science and Education (ORISE) performed in-process inspection survey activities of the Reactor Support Structure (RSS) at the Yankee Nuclear Power Station (YNPS) Plant in Rowe, Massachusetts on September 15,2004. Survey activities included document and data reviews, beta surface scans, and beta surface activity measurements.
The RSS is a rebar-reinforced concrete structure that supported the polar crane consisting of two concentric concrete cylinders (the outer and inner cylinders). The cylinders were connected together with rebar-reinforced concrete radial walls which formed compartments that housed the Main Coolant Loops, Pressurizer, Equipment Hatch and associated supporting components including piping and valves, reactor coolant pumps, steam generators, HVAC systems, he1 transfer systems, a fuel manipulator crane, and a polar crane. The compartments were covered by a rebar-reinforced concrete charging floor. The charging floor had concrete blocks, that have since been removed, which allowed the crane to access all the compartments (YAEC 2004).
The RSS has undergone initial remediation activities which first included polychlorinated biphenyls (PCB) decontamination of the outer cylinder followed by radiological surveys of the post-PCB remediated areas. All systems and components have been removed from the RSS and all interior and exterior surfaces have been remediated. The radiological surveys consisted of 100 percent surface scans of the outer cylinder and included all penetrations in the wall. Areas and penetrations that met approved guideline values were covered with plastic sheeting or capped. The inner cylinder was surveyed using the same methodology as the outer cylinder with the exception of the lower portion where decontamination efforts were suspended due to extensive contaminated areas and seismic concerns (YAEC 2004).
P 0 BOX 117, OAK RIDGE, TENNESSEE 37831-01 17 Managed and operated by Oak Ridge Associated Universities far the U S Department of Energy
Mi-. John Hickman 2
March 30, 2005 ESSAP was to perform confirmatory survey activities on the various surfaces of the RSS in accordance with the NRC-approved site-specific survey plan and the ORISEESSAP Survey Procedures and Quality Assurance Manuals (ORISE 2004a, b, and c). While the survey plan called for confirmatory surveys of portions of the RSS, YNPS had not completed final status surveys of all areas as planned. The site-specific confirmatory survey plan was followed but the ESSAP-collected data represent an in-process inspection activity rather than a confirmatory survey. Survey activities consisted of beta surface scans, total beta surface activity measurements, and smear sampling for removable alpha and beta activity.
For the RSS, it was also the intent to perform side-by-side direct measurements for direct datdinstrument comparisons. On the first instrument comparison survey attempt, YNPS personnel used a Ludlum Model 43-37 gas proportional detector which has a much larger surface area than ESSAPs Ludlum Model 43-68 gas proportional detector and was not conducive to direct instrument comparison. This was discussed with YNPS, NRC, and ESSAP personnel and a second instrument comparison attempt was performed. During this attempt, the YNPS instrumentation malfunctioned; therefore, a direct datdinstrument comparison was not performed. In the interim, ESSAP performed direct measurements at 18 randomly selected locations on various RSS surfaces; beta radiation surface scans were performed in the immediate vicinity of the direct measurement locations. Beta surface scans and direct measurements were performed using gas proportional detectors coupled to ratemeter-scalers with audible indicators.
Both unshielded and shielded measurements were performed at each location. Smear samples, for determining removable gross alpha and gross beta activity levels, were collected at each direct measurement location. Figures 1 and 2 document direct measurement and smear sampling locations.
Smear samples and data were returned to ESSAPs Oak Ridge, Tennessee facility for analysis and interpretation. Samples were analyzed in accordance with the ORISEESSAP Laboratory Procedures Manuals (ORISE 2004d). Smears were analyzed for gross alpha and gross beta activity using a low background gas proportional counter. Smear data and direct measurements for surface activity were converted to units of disintegrations per minute per 100 square centimeters (dpdl00 cm2).
The primary contaminants of concern for the YNPS are beta-gamma emitters-fission and activation products-resulting from reactor operation. Cesium-137 and Co-60 have been identified during characterization as the predominant radionuclides present on surfaces.
For the RSS, the site-specific guideline values per the draft license termination plan (LTP) are as follows (YAEC 2003):
Total Activity 5,000 dpd100 cm2, maximum in a 100 cm2 area Removable Act ivi tv 1,000 d p d l 0 0 cm2
Mr. John Hickman 3
March 30. 2005 Total and removable surface activity levels for the RSS are presented in Table 1. Total surface activity levels ranged from 250 to 256,900 dpm/100 cm2. Survey results indicated that six of the 1 8 randomly selected measurement locations were above the 5,000 dpm/l 00 cm2 guideline.
Removable surface activity levels ranged from 0 to 3 dpd100 cm2 for alpha and -3 to 397 dpm/ 100 cm2 for beta.
The in-process survey activities determined that surface activity levels above the site-specific guideline values are present on various surfaces throughout the RSS.
At the request of the NRC site representative; this letter report was finalized to include the uncertainties in the surface activity measurements. If you have any questions or comments, please direct them to me at (865) 576-0065 or Timothy J. Vitkus at (865) 576-5073.
Wade C. Adams Health PhysicistProject Leader Environmental Survey and Site Assessment Program WCA:ar Enclosures cc:
T. McLaughlin, NRC/NMSS/TWFN 7F27 E. Abelquist, ONSEESSAP E. Knox-Davin, NRC/NMSS/TWFN SA23 J. Kottan, NRClRegion I File/1621 T. Vitkus, ORISE/ESSAP M. Miller, NRCRegion I
1621-013 (1)
MEASUREMENT/SAMPLING LOCATIONS
- SINGLE-POINT LOWERWALLSANDFLOOR 1
NOT TO SCALE I
FIGURE 1 : U S, VC Broadway and Charging Floor - Measurement and Sampling Locations YNPS Reactor Support Structure projects/l621/Reports/2005-03-30 RSS Letter Report
1621-014 (1)
MEASUREMENTISAMPLING LOCATIONS
- SINGLE-POINT
- UPPERWAJLS f
NOT TO SCALE FIGURE 2: RSS, VC Chargmg Floor - Measurement and Sampling Locations YNPS Reactor Support Structure projectsl16211Reports/2005-03-30 RSS Letter Report
TABLE 1 SURFACE ACTIVITY LEVELS REACTOR SUPPORT STRUCTURE YANKEE NUCLEAR POWER STATION ROWE, MASSACHUSETTS Broadway 88 4,5 10 + 630" 1 +4d 5 + 7 89 2,550 + 630 O + l
-3 + 4 90 3,530 -e 770 1 + 4
-3 & 4 91 1,890 + 610 0 2 1
-1 + 5 Charging Floor 92 75,400e + 2,300 o + 1 3 + 6 I
I I
93 86,70Oe + 2,300 0 + 1 8 + 8 19A 33,600e f 1,200 0 + 1 51 & 16 20A 330 + 440 O + l
- 2 + 5 21A 330 + 420 1 +4 3 + 4 22A 3,930 + 570 Oa 1
-1 2 5 23A 250 + 430 o + 1 4 + 7 24A 256,900" + 2,900 3 + 5 397 +44 25A 3,670 f 550 1 + 4
-1 + 5 2 6A 2,830 k 530 0 + 1
-1 + 5 28A 4,960 + 560 0 + 1
-1 + 5 27A 8,480e f 700 O r 1 7+.8 29A 2,940 + 540 0 + 1 6 + 7 30A 7,370e + 660 o + 1
-4 + 3 "Refer to Figures 1 and 2.
hTotal beta activity was calculated by subtracting the ambient background as determined by shielded and unshielded measurements, then correcting for the total efficiency and detector area size.
'Total beta activity uncertainties represent the 95% confidence level based only on counting statistics.
dRemovable activity uncertainties represent the 95% confidence level based on total propagated uncertainties.
'Measurement locations exceed site-specific guideline values.
YNPS Reactor Support Structure projects/l621/Reports/2005-03-30 RSS Letter Report
REFERENCES Oak Ridge Institute for Science and Education (ORISE). Confirmatory Survey Plan for the Primary Auxiliary Building and Portions of the Reactor Support Structure, Yankee Nuclear Power Station, Rowe, Massachusetts [Docket No. 50-29; RFTA No. 04-0071. Oak Ridge, Tennessee; September 8,2004a.
Oak Ridge Institute for Science and Education. Survey Procedures Manual for the Environmental Survey and Site Assessment Program. Oak Ridge, Tennessee; September 2, 2004b.
Oak Ridge Institute for Science and Education. Quality Assurance Manual for the Environmental Survey and Site Assessment Program. Oak Ridge, Tennessee; August 3 1,2004~.
Oak Ridge Institute for Science and Education. Laboratory Procedures Manual for the Environmental Survey and Site Assessment Program. Oak Ridge, Tennessee; August 3 1, 2004d.
Yankee Atomic Electric Company (YAEC). Draft - Yankee License Termination Plan, Rowe, Massachusetts; September 2003.
Yankee Atomic Electric Company. Yankee Atomic Electric Company Sample Plan: Reactor Support Structure Survey Protocol. Rowe, Massachusetts. June 2004.
YNPS Reactor Support Structure projects/l621/Reports/2005-03-30 RSS Letter Report