ML20198H284
| ML20198H284 | |
| Person / Time | |
|---|---|
| Site: | 07000824 |
| Issue date: | 05/14/1986 |
| From: | Olsen A BABCOCK & WILCOX CO. |
| To: | Crow W NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| 26974, NUDOCS 8605300247 | |
| Download: ML20198H284 (6) | |
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RETURN TO 396-SS Research & Development Division Babcock & Wilcox tynendurg neseeren center a McDermott company P. O. Box 11165 Lynchburg, Virginia 24506-1165 (804) 522 6000 May 14, 1986 Mr. W. T. Crow, Section Leader
- s Uranium Process Licensing Section N,
tum Fuel Licensing Branch gg q
MAY 161986 MAY 18 92 > b Wa h n t n D 43.MUCtIAR REGMM Q*
Most h
U License: SNM-778, Docket 70-824 C "n"$s "hsj
/7 Mau Section
Subject:
Building C Decommissioning iG
References:
(1)
Letter, dated May 28, 1985, A.
F. Olsen to W.
T. Crow, forwarding Phase I"
" Decontamination and Decommissioning of Building C RDD:85:8604-01:01, May 1985.
(2)
Letter, dated February 13, 1986, J. P. Stohr to T. C. Engelder, for-warding inspection Report No. 70-824/85-08 (3)
Letter, dated March 25, 1986, A.
F.
Olsen to Uranium Processing Section, forwarding responses to Reference (2).
Dear Mr. Crow:
This is to provide additional survey data to respond to a question found in Section 7.c of Reference (2).
The final survey report for Phase I of the Building C decommissioning project was forwarded by Reference (1).
Reference (2) forwarded the report from Region II of the results of the close out inspection performed during November, 1985.
In Reference (2), Region II questioned whether the surveys in the front portion of Old Central Stores, which had not been used for handling or storing licensed materials, were sufficiently thorough.
In response to this, the Lynchburg Research Center, in Reference (3), agreed to perform additional random surveys for alpha and beta contamination in the Old Central Stores to complement the surveys already performed.
These additional surveys have been performed and the resul ts are presented in the attached supplement to the survey report.
By way of explanation, in Table A-2, the underlined numbers at the top of the four columns, namely, 0, 3, 6, and 9, are contamination levels in DPM/100 cm2 The numbers below these headings are the number of smears that fall within each column value at the indicated location.
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Mr. W. T. Crow' May 14, 1986 Page 2 As mentioned in Reference (2), the area in question had not been used to handle or store licensed material.
This additional information supports that statement and shows that no contamination is present in the area.
This concludes the responses requested by Region II on the decommis-sioning of the Phase I portion of Building C.
Very truly yours, BABC0CK & WILC0X AOL Arne F. Olsen Senior License Administrator Lynchburg Research Center pc:
With attachment Director, Region II i
T. C. Engelder i
G. S. Hoovler I
I l
l ATTACHMENT A OLD CENTRAL STORES i
SUPPLEMENTAL SURVEY REPORT i
l RESPONSE TO NRC REPORT NO. 70-824/85-08 FORWARDED BY 2/13/86 LETTER FROM J. PHILLIP ST0HR TO T. C. ENGELDER i
l
A-1 Survey Plan / Procedures The floors and walls in the Old Central Stores area of Building C were divided into 1 m2 (or less) grids.
Random, uniformly dispersed direct alpha and beta surveys were performed in each accessible grid.
Small area (100 cm2) smears were taken from each accessible grid.
Each smear was counted for alpha activity.
Twenty-five percent of these smears were also y
counted for beta activity.
Otherwise, the procedures and release criteria for performing and documenting these surveys were the same as described in reference (1).
A-2 Survey Instruments The same aloha and beta survey instruments described in reference (1) were used.
The direct surveys were performed with calibrated PAC-4G meters coupled to 50 cm2 probes (beta) or 335/445 cm2 probes (alpha).
Because of background radiation levels, the lower limit of detection for the direct beta survey instrument was 2000 DPM/100 cm2 The detection limit for the alpha survey instrument was 30 DPM/100 cm2 The alpha and beta background levels for the smear counter corresponded to 0.1 and 200 DPM/100 cm2, respectively.
l A-3 Survey Results and Conclusions A total of 2032 direct alpha and 2516 direct beta surveys were per-formed.
These were distributed among 472 grids as outlined in Table A-1.
All readings were equal to background.
A total of 456 smears were counted for removable alpha contamination.
The results are summarized in Table A-2.
Of this total, all were less than 50% of the allowed release limit of 20 DPM/100 cm2, and 95% were less than 3 DPM/100 cm2 About 25% (107) of these smears were counted for beta activity.
All were less than 100 DPM/100 cm2 4
s
As mentioned in reference (1), licensed materials were not handled in the front part of Old Central Stores.
The survey results reported above corroborate the assumption (based on history and a few smear surveys) that there was no contamination in this area.
It is concluded that this area meets or surpasses the surface contamination criteria specified for un-restricted release of the facility.
TABLE A-1.
OLD CENTRAL STORES 1
WALLS AND FLOORS, NUMBER OF DIRECT SURVEYS 3;.-
No. Dipect, Alpha No. Direct Beta Surface No.-Grids-
- Surveys Surveys
,tu South Wall
~E6' ~
~
~
... 1,,,.g, -
242 18.s West Wall 76 g;q 266 y ni 340 East Wall 76 _.
WA 198.-l'O' 284 Ah
'I North Wall 56-
~188-245 men A:
..._ J Floor 20 F E99 1405
_ __1 M o
_.}T '
- ' *1 et t n-TABLE A-2.
OLD-CENTRAL-STORES 'WAltS' AND~ FLOORS REMOYABLE ALPHA SURVEY RESULTS.
=
n
. -- ~~ -NumberW1emovable' Alpha Readings at SpecifiedtContamination Level, DPM/100 cm2 4
Surface 0
3 6
9 South Wall 38 13 4
1 West Wall 54 18 4
0 East Wall 57 17 2
0 North Wall 42 13 1
0 Floor 127 53 11 1
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