ML19338F909
| ML19338F909 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 01/29/1975 |
| From: | Autio H YANKEE ATOMIC ELECTRIC CO. |
| To: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| Shared Package | |
| ML19338F906 | List: |
| References | |
| NUDOCS 8010270611 | |
| Download: ML19338F909 (8) | |
Text
D/l h.32f Q*({
i r
O YAlll[EE ATOUIC ELECTRIC COMPANY Rowe, Massachusetts 01367
,~.NIKEE January 29, 1975 United States Nuclear Regulatory Commission Directerate of Re'ulatory Operations g
Region I 631 Park Avenue King of Prussia, Pennsylvania 19406
Reference:
License No. DPR-3 (Docket No. 50-29)
Gentlemen:
In accordance with the requirements of Section 20.405 (a)
(1) of 10 CFR 20, Yankee Atomic Electric Company hereby reports the fact that the plant records indicate that six individuals were exposed to airborne concentrations of radioactive material in excess of the provisions of Section 20.103 of 10 CFR 20.
The records upon which this conclus' ion is based consist of the airborne sampling measurements obtained in the area of
' Steam Generator No. 4 during the period June 3, 1974 through June 9, 1974.
A brief outline of the work that was being performed on SG No. 4 during this period is as follows:
June 3, 1974 I'nspection for tube leaks June 4, 1974' Tube sheet inspection and survey June 6, 1974 Eddy-current examination and tube marking June 7, 1974 Tube plugging June 8, 1974 Tube grinding, plugging and inspection June _9, 1974 Tube sheet inspection and tube plugging The above work was performed by a combination of three permanent plant st'aff members and three contractor employees.
The following delineates the exact participation of each individual involved:
8010270 6//
v
Directorate of Regulatory Operations Page Two
/
<Jandary 29, 1975 Individual #
SG No. 4 Work Performed 1
June 3, 1974 Inspection June 4, 1974 Inspection and survey June 6, 1974 Eddy-current examination June 7, 1974 Tube plugging June 8, 1974 Tube plugging June 9, 1974 Tube plugging 2
June 3, 1974 Inspection June 7, 1974 Tube plugging June 8, 1974 Tube grinding 3
June 4, 1974 Inspection and survey June 6, 1974 Eddy-current examination June 8, 1974 Inspection 4
June 4, 1974 Inspection and survey June 6, 1974 Eddy-current examination June 7, 1974 Tube plugging June 8, 1974 Tube plugging June 9, 1974 Tube plugging 5
June 3, 1974 Inspection June 4, 1974 Inspection and survey June 6, 1974 Tube marking 6'
June 4, 1974 Inspection and survey June 6, 1974 Eddy-current examination A review of Loop No. 4 airborne sampling records and radiation work permits for the period indicate that the above individuals were performing their duties within working environments with average airborne concentrations of insoluble radionuclides and for total e.posures times as follows:
Directorate of Regulatory Operations Page Threc
/
.f
' ' January 29, 19751 Average Airborne Total Exposure Concentration Time Individual #
(uCi/cc)
(hours) 1 7.25 x 10-7 10.8 2
4.23 x 10-7 4.83 3
2.36 x 10-7 7.5 4
7.25 x 10-7 9.72 5
6.09 x 10-7 3.6 6
6.88 x 10-7 1.75
- Total of all radionuclides identified to be present.
Based on the results of gamma spect.roscopy measurements of representative Loop No. 4 airborne samples, the radionuclides and their relative activity distribution within the above average airborne concentration totals were as follows:
Radionuclide Distribution (s)
Co-57 0.077 Co-58 28.0 Co-60 40.8 Cr-51 10.4 Zr-95 0.4 Mn-54 10.0 Fe-59 5.9 Sb-124 1.7 Nb-95 2.7 The effective occupational 40 hr. MPCa for the above distribution of radionuclides is 1.8 x 10-8 uCi/cc.
Using this effective MPCa the above stated average airborne concentrations and total exposure times the individuals were, by calculation of airborne exposure without applying any credit for respiratory j
protective devices, exposed to the following values of MPCa hours i
during the entire seven day period:
(
w,
-w w-
leJ1recgorage oLn;feYd1Favory @peraTE@ng P, age Four f'
f
-January 29, 1975 9.
Total Exposure Factor Above Individual #
MPCa hours) 20.103 1
433 10.8 2
113.4 2.8 3
97.9 2.4 4
389 9.7 5
121 3.0 6
66.5 1.7 Dose commitment calculations have been performed for the individuals for the above stated exposure concentrations and durations.
The results are as follows:
Total Dose Commitment (D= ) (rems)
Individual #
Lung LLI 1
3.58 0.18 2
0.94 0.048 3
0.81 0.041 4
3.22 0.163 5
1.00 0.05 6
0.55 -
0.028 As previously mentioned, the exposure concentrations, factors above Section 20.103, and dose commitments presented above are all based on exposure calculations without the application of any credit for respiratory protection devices that were actually employed for the individuals involved.
During the conduct of all the SG No. 4 work during this period, each of the six individuals was provided respirctory protection in the form of a full face respirator with either bottled supplied air operated in the demand flow mode, or a particulate filter.
Per Table 6.1 of h' ASH-1287, the respiratory protection factor applicable to this form of protection is 100.
Such a protection factor cannot be applied to these exposures because technically, the plant does not have an "appreved" respiratory protection program in all respects.
The issuance of the draft modification to Section 20.103 of 10 CFR 20 in August, 1974 precipitated a thorough review of the current respiratory protection program at the plant.
This. review has been completed and company management has approved the extensive recommendations
birectorage of kegulagory OperaW1ons Page.Five f
f Jdn'uary 29, 19754-for program improvement that the Plant Health Physics staff requested.
Equipment is being purchased and within the next year program improvements will be such that the plant will have the respiratory protection program called for the current draft change to 20.103.
As for a demonstration of the actual respiratory protection afforded these individuals during the SG No. 4 work, data on the measured amounts of actual internal deposition of the airborne radionuclides is available in the form of body burden counting records.
Each of the six individuals was analyzed in the Yankee mobile body burden counter following the completion of the subject work.
The results of these measurements indicate that the actual respiratory protection factors attributable to these exposures range from a low of 5.5 tc a high of 22 for the radionuclides identified in the body burden counting.
We attribute this anomoly to the people being counted at various time intervals subsequent to the steam generator work and having been in an environment where measurable concentrations of airborne activity existed.
The implied protection factors would also be lower than expected if some portion of the activity indicated by the body burden analysis is due to external examination of the individual.
Dose commitment calculations have been performed for the individuals based on the results indicated by the body burden analyses.
The results are as follows:
Individual #
Total Dose Commitment (D= ) (rems)
LUNG LLI 1
0.32 0.014 2
0.066 0.002 3
0.085 0.004 4
0.145 0.007 5
0.01 0.004 6
0.1 0.004 As to an identification of the cause of the situation necessitating this report, a review has been performed of the radiation protection criteria that were applied to the SG No. 4 related work.
This review has revealed that a misinterpretation
Directoragd of Regunatory Operations Page.Six
/
'J'anuary 29, 197L of previous work practices occurred at the plant prior to the shutdown.
In previous steam generator work the individuals working within the water box were provided with full environmental isolation.
During the 1974 refueling other personnel directly associated with the steam generator work in areas outside of the water box were provided with respiratory protection, but not full environmental isolation; and were inadvertently considered to be covered by previous steam generator work practices.
In addition, body burden counting was not promptly completed on all affected personnel.
As for corrective action to prevent recurrence of the over-exposures indicated herein, a three point program has been initiated.
They are as follows:
1.
The misinterpretation that steam generator work is exempted from 20.103 limitations has been corrected.
The radiation protection criteria employed in the
- past, i.e. that the I.quirements of 20.103 are to be complied with, is to be implemented.
2.
A review of the specifics involved in steam generator inspection eddy-current examination, and tube plugging will be conducted for the purpose of identifying whether further application of engineering controls is possible to effect a reduction in airborne levels of radioactivity associated with steam generator wolk.
A loop purge and filtration system was utilized during this most recent shutdown.
It will be reviewed in relation to the problem and modified if possible.
3.
As previously mentioned, a thorough review of the upcoming requirements (draft change to 20.103) of an acceptable respiratory protection program has been completed and has resulted in approval of extensive improvements such that as soon as equipment can be supplied and procedures written the plant will have a program that complies with the modified 20.103.
It is anticipated that these improvements will be completed within the next year.
Page Seven
. Janua'ry 29, 1975y It is recognized that the timeliness of this report is not in accordance with the requirement of 20.405.
The reason for the delay is attributable to.the previously described misinterpretation regarding the application of 20.103 limitation to steam generator work.
The assumption that this work was exempted meant, that there was no reporting requirement.
The recently conducted review of the plant's respiratory protection program in relation to the draft change to 20.103 brought the misinterpretation to light and, therefore, the reporting obligation.
Pursuant to 10 CFR 19.13(d), a copy of this modification has been forwarded to the subj ect individuals.
We trust you will find this notification satisfactory; however, should you desire any additional information feel free to contact us.
Respectfully submitted, l
YANKEE ATOMIC ELECTRIC COMPANY H. A. Autio Plant Superintendent HAA/ meg 1 Enclosure cc:
(6) Director of Regulatory Operations United States Nuclear Regulatory Commission Washington, D. C.
20555 (1) Each individual on enclosure 4
J
~
O O
ENCLOSURE r0 YANKEE ATOMIC 10 CFR 20.40~$ (a)
~
NOTIFICATION REPORT Dose commitment calculations based on body burden-analysis.
.-