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Insp Repts 50-369/85-22 & 50-370/85-23 on 850610-14. Violations Noted:Failure to Post Radiation Area & Skin Exposure in Excess of 10CFR20.101(a) Limits
	ML20133Q284
Person / Time
Site:	Mcguire, McGuire
Issue date:	08/02/1985
From:	Hosey C, Weddington R; NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To:	;
Shared Package
ML20133Q202	List: ML20133Q200; ML20133Q256; ML20133Q284;
References
	50-369-85-22, 50-370-85-23, NUDOCS 8508150089
	Download: ML20133Q284 (9)
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Report Nos.: 50-369/85-22 and 50-370/85-23

Licensee: ~ Duke Power Company

422 South Church Street

Charlotte, NC 28242

Docket Nos. : 50-369 and 50-370 License Nos.: NPF-9 and NPF-17

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Facility Name: McGuire 1 and 2

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Inspection Conducted: June 10 - 14, 1985 and Enforcement Conference July 12, 1985

Inspec"or: hNi

V R. E. Weddington

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Date Signed

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! Accompanying Personnel:, T. G. Lee

Approved by: cPA N2./8I

C. M. Hos'ey? Sectioi Chief Date Signed

Division of Radiation Safety and Safeguards

SUMMARY

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Scope: This special, unannounced inspection involved 34 inspector-hours on-site

responding to a report of an apparent exposure to the skin of the whole body of a

i licensee employee in excess of the limits of 10 CFR 20.101(a).

Results: Two violations were identified: (1) exposure to 1 cm2 of the skin of

the whole body of a licensee employee in excess of the limits of 10 CFR 20.101(a)

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and (2) failure to post a radiation area.

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REPORT DETAILS

1. Persons Contacted

Licensee Employees

T. L. McConnell, Plant Manager

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J. W. Foster, Station Health Physicist

j *N. McCraw, Compliance Staff

W. F. Byrum, Health Physics Staff

B. Hamilton, Superintendent of Technical Services

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B. Travis, Scheduling

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D. J. Rains, Superintendent of Maintenance

P. B. Nardoci, General Office Licensing Staff

T. Keane, Corporate Health Physicist

Other licensee employees contacted included two foremen, six technicians, a

mechanic, a nuclear equiprcent operator and two office personnel. ,

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NRC Resident Inspectors

i *W. Orders, Senior Resident Inspector

l R. Pierson, Resident Inspector ,

Attended exit interview ,

2. Exit Interview

The inspection scope and findings were summarized on June 17, 1985, with

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those persons indicated in paragraph 1 above. The following issues were

discussed in detail: (1) an apparent violation for exposure to the skin of

the whole body of a licensee employee in excess of the limits of

10 CFR 20.101(a) (paragraph 3) and (2) an apparent violation for failure to

post a radiation area (paragraph 4). The licensee acknowledged the

inspection findings and took no exceptions. The licensee did not identify

j as proprietary any of the materials provided to or reviewed by the inspector

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during this inspection.

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3. Overexposure Investigation (92700)

On June 7,1985, the licensee notified Region II that a licensee employee

had apparently received an exposure to the skin of his whole body of

10.6 Rems, which is in excess of the quarterly skin exposure limit of

i 7.5 Rems given in 10 CFR 20.101(a). The exposure was caused by a single

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cobalt-60 (Co-60) particle that was discovered on the worker's skin when he

exited the Unit 1 containment.

l Through discussions with licensee representatives, the inspector determined

that the individual in question was a contractor employee supporting the

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Unit I steam generator tube plugging. At approximately 2200 hours0.0255 days 0.611 hours 0.00364 weeks 8.371e-4 months on

June 5,1985, the individual exited the Unit I lower containment access

after having assisted another contractor employee who was plugging tubes

inside the 1-D steam generator. The individual had primarily worked from

the steam generator platform with video cameras. The licensee had

positioned an Eberline PCM-1 portal monitor in the vicinity of the contain-

ment exit to perform a prt:liminary contamination check prior to personnel

going to the whole body frisking station in the vicinity of the change rooni.

After removing his protective clothing at the containment exit, the worker

stepped into the portal monitor and set off the alarm. Heal th physics

personnel determined that the worker was contaminated in the vicinity of his

left arm pit by using a RM-14 portable frisker with hand-held probe,

however, the amount of contamination could not be quantified due to it

exceeding the maximum scale of the instrument (50,000 counts per minute). A

survey was then performed using an Eberline R0-2 beta-gamma survey meter

which indicated that the contamination was reading 0.5 millirem per hour

, gamma and 58 millirem per hour betc.

The worker was decontaminated by wiping the contaminated area with a wet

paper towel. The decontamination material was retained and was determined

by analysis on a GeLi dectector to be a single 1.2 microcurie particle of

Co-60.

It appeared that the Co-60 particle had remained on the inside of the

protective clothing worn by the worker after they were laundered and was

subsequently transferred to the worker's skin after he put them on. The

individual had worn a plastic suit over the top of his protective clothing

inside the containment and there was no evidence that the plastic suit had

been torn or damaged.

Personnel from the licensee's corporate health physics staff performed

calculations to determine the amount of exposure the individual had incurred

due to this contamination event. It was assumed that the exposure was

received over an approximately two hour period from the time the protective

clothing was put on in the dressing room until the contamination was

successfully removed. The resulting exposure estimate was 10.6 Rem to the

skin of the whole body distributed over a one square centimeter area, which

when added to the previous skin of the whole body exposure during the

current calendar quarter of 580 millirem, gave the individual a total dose

for the calendar quarter of 11.18 Rem to the skin of his whole body.

The licensee believed that the high activity Co-60 particles were produced

by neutron activation of elemental cobalt found in stellite. During

previous outages valves composed of stellite had been lapped in place inside

the containment. Studies performed by the licensee indicated that as much

as 40 percent of the debris produced by this process remained on the valve

seat even after cleaning. This material was transported through the reactor

core by the primary coolant and subsequently plated out on the interior of

the primary piping. Smears performed by the licensee inside containment

during the current outage were determined to contain high activity Co-60

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particles mixed with other contaminants. Licensee surveys of the facility

revealed the only place that these high activity Co-60 particle were

discovered disassociated from other contaminants was in the contaminated

laundry area. On June 7, 1985, a 0.5 microcurie Co-60 particle was found

on the floor of the laundry area while performing a massolin mopping of the

area. A licensee representative stated that a high activity Co-60 particle

had also been discovered inside one of the clothing dryers. Since the

laundry area was the only place that these high activity Co-60 particles had

been identified disassociated from other contaminants, the licensee

determined that the likely source of the personnel contamination was the

laundered protected clothing. The circumstances surrounding the event of

June 5,1985, and other previous contamination events also support the

conclusion that high activity Co-60 particles remained on the protective

clothing after laundering and was the source of the personnel contamination.

The licensee had documented seven other contamination events that they

believed were similar and that occurred prior to the one that had caused the

apparent overexposure. These events occurred during the period April 12

through May 31, 1985. Five of the seven events involved personnel

contaminations discovered after individuals had worked in protective

clothing. The contamination levels associated with these events ranged from

6000 counts per minute to a single particle reading 490 millirem per hour

i beta. The exposure estimates to the skin of the whole body of the

contaminated individuals ranged from 15 to 5510 millirem.

As these contamination events occurred the licensee initiated a number of

actions to identify and eliminate the source of the contamination. The

laundry operation was identified as a likely source of the problem early on

in the licensee's investigation. Independent of the personnel contamination

problem,'the licensee had started using an off-site contractor to laundry

used protective clothing. The licensee was using the off-site contractor

laundry service when the second and third contamination events occurred on

May 2 and 3, 1985 occurred. The licensee terminated the service contract

and began laundering used protective clothing on-site again to preclude any

possibility that the licensee's protective clothing was being cross con-

taminated at the contractor laundry by washing with contaminated clothing

from other facilities.

The permissible level of contamination the licensee permitted on laundered

protective clothing was one millirem per hour. The survey on laundered

protective clothing had consisted of a frisk with a portable beta-gamma

survey _ meter with hand held probe paying close attention to the knees,

elbows, arms and ' seat with the rest of the clothing receiving a less

detailed scan. When the licensee began laundering protective clothing again

on-site in mid May 1985, they began a detailed survey of the outside of each

item of clothing after it came from the dryer. They also, for a period of

time, surveyed the protective clothing in the dressing room innediately

prior to the individual putting it on. After the apparent overexposure

event on June 5, 1985, they began to perform detailed frisks of the inside

and outside of each item of protective clothing after it was laundered.

. After several days, the surveys were relaxed to just the outside of each

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item. On June 13, 1985, the licensee informed the inspector that they were

going back to frisking both the inside and outside of the laundered garments

based on a corporate health physics staff evaluation of the question. As a

long term solution to the problem, the licensee stated that they are

pursuing obtaining an automated clothing scanner.

The licensee had required that personnel working in the laundry wear a

labcoat and rubber gloves, which was changed to a full set of protective

clothing in mid May 1985. A frisker was also installed at the exit from the

laundry and all personnel leaving the area were required to perform a whole

body frisk.

The licensee also changed several of their limits within the laundry area.

The licensee had permitted protective clothing contaminated up to

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50 millirem per hour to be laundered. The licensee decreased the limit to '

25 millirem per hour, however, a licensee representative stated that they

would further decrease the limit to 10 millirem per hour by July 1,1985.

The licensee also surveyed the washer and dryer for contamination after each

load was removed. Massolin moppings of the laundry area floor every shift

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was implemented.

The licensee implemented a color coding and segregation procedure for

protective clothing. White protective clothing was worn next to the

worker's skin and was worn as the outer garment in areas of low contamina-

tion potential. Yellow protective clothing was used as the outer suit when

double layers of protective clothing were required. A yellow plastic suit

was also required over the double layer of protective clothing in areas of

high levels of contamination, such as inside the steam generator. The

yellow and white protective garments were segregated after use and laundered

separately. The licensee also replaced all of their old protective clothing

with new protective clothing on June 10, 1985.

The licensee had placed a portal monitor at the entrance to the radio-

logically controlled area to determine if personnel were being contaminated

by these high activity Co-60 particles from some unidentified source outside

of the controlled area. No problem of this nature was detected and the use

of the entrance portal monitor was discontinued.

The licensee conducted an inventory of all their sealed sources,

particularly those used in radiography, and determined that none were

missing. Leak checks also revealed that all of the Co-60 sources were ,

intact. During the inspection, the inspector examined the source storage

area and accountability log and determined that proper source control was

being maintained and that there were no records of missing sources.

f The licensee had conducted a special grid survey of the facility to deter-

I mine if there was some previously unidentified soum ' of the contamination.

No such source was identified. The licensee aP,o splemented periodic

massolin moppings of the uncontrolled areas t thr iuxiliary building,

laundry, changeroom, and the pathway from th' ,' sad . om to the containment

accesses. On June 7,1985, a 0.5 microcuries Co-60 particle was discovered

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in the protective clothing laundry area. This was the only area that pure

Co-60 contamination was discovered during these surveys. Contamination was

discovered on three other occasions during the period June 8 - 11, 1985 in

uncontrolled areas of the auxiliary building by these mop surveys. The

contamination was isolated spots up to 6000 counts per minute and contained

a number of other radionuclides in addition to Co-60. These three instances

were not significant considering the number of surveys that had been

performed and their relatively small activity and was not indicative of any

programmatic weaknesses in the licensee's contamination control program.

The inspector interviewed six of the eight personnel who had received skin

exposures as a result of the previously discussed contamination events,

including the worker who had received an apparent overexposure on June 5,

1985. The worker's account of the events were consistent with the

licensee's investigation reports. It appeared that the laundered protective

clothing was the likely source of most of the contamination events.

During tours of the facility, the inspector observed activities in progress

in the protective clothing laundry area, at the Unit 1 containment accesses,

the hot machine shop and in the change rooms. Work was performed in

conformance with posted radiation work permits. Housekeeping appeared very

good, particularly since the unit was in an outage. Acceptable contamina-

tion controls were observed while removing material from contaminated areas.

Health physics personnel were observed closely following work in

contaminated areas. Personnel were also observed performing thorough whole

body frisks upon exiting contaminated areas. The surveys of laundered

protective clothing were being performed by health physics personnel. Only

a small number of garments were being discarded because of excessive

residual contamination.

The inspector reviewed the licensee's reports of personnel skin contamina-

tions for the period January through May 1985. A total of 268 events were

documented during this period. Thirty-four of these events resulted in the

licensee assigning skin of the whole body doses to the employees concerned.

The majority of the dose assignments were less than 100 millirem. Only 8

of these 34 events, as discussed previously, involved high activity isolated

Co-60 particles and potentially contaminated laundered protective clothing

as a likely source of the contamination. No other pattern or evidence of a

programmatic type problem was observable in the description of these events.

Based on the above, it was determined that seven workers had received

exposures from skin contamination due to high activity isolated Co-60

particles being transferred from the interior of laundered protective

clothing. One of these events, the one of June 5,1985, had resulted in an

exposure to the skin of an employee's whole body of 10.6 Rem, which when

added to his previous skin exposure for the calendar quarter of 580 milli-

rem, resulted in his receiving a dose of 11.18 Rems to the skin of his whole !

body. 10 CFR 20.101(a) requires that no licensee shall posses, use, or I

transfer licensed material in such a manner as to cause any individual in a

restricted area to receive in any period of one calendar quarter from

radioactive material and other sources of radiation a total occupational l

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dose in excess of 7.5 Rems to the skin of the whole body. The exposure

event of June 5,1985, which resulted in a licensee employee receiving a

total exposure of 11.18 Rems to the skin of his whole body, was identified

as an apparent violation of 10 CFR 20.101(a)(50-369/85-22-01 and

50-370/85-23-01).

On July 5, 1985, the licensee submitted a Licensee Event Report (LER)

describing the circumstances of the exposure event and giving the employee's

total quarterly exposure to the skin of the whole body as 11.18 Rems.

4. Control of Radiation Areas (83724)

10 CFR 20.203(b) requires that each radiation area shall be conspicuously

posted with a sign or signs bearing the radiation caution symbol and the

words: " Caution-Radiation Area."

During the inspection, the inspector performed surveys in the auxiliary and

service buildings, in the radioactive waste area and in areas around the

plant site outside of the buildings.

On June 13, 1985, the inspector discovered an area along the soutn wall of

Room 637 on the 716' elevation of the auxiliary building that had dose rates

i of 72 millirem per hour at near contact with the interface area of the wall

and floor and 6 millirem per hour at 18 inches and at approximately waist

height in the vicinity of the source. The survey was performed with XETEX

305B, portable beta gamma survey meter, serial number 3685, calibration due

March 20,1986. The area was not posted as a radiation area. The licensee

verified the radiation levels with their own survey instruments and posted

the area. A licensee representative stated that the likely source of the

radiation area was a pipe trench that ran under the floor that connected the

Units 1 and 2 valve galleries. The pipe trench contained piping that had

required shielding in the past. Failure to post the radiation area was an

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apparent violation of 10 CFR 20.203(b) (50-369/85-22-02 and

50-370/85-23-02).

5. Enforcement Conference

An Enforcement Conference was held at NRC Region II on July 12, 1985, to

discuss the exposure of a licensee employee apparently in excess of the skin

of the whole body quarterly exposure-limits given in 10 CFR 20.101(a). The

following persons were in attendance:

a. Duke Power Company

H. B. Tucker, Vice President, Nuclear Production

W. A. Haller, Manager, Nuclear Technical Services

T. L. McConnell, Station Manager

J. Foster, Station Health Physicist

N. McCraw, Station Compliance Engineer

R. Gill, McGuire Licensing, General Office

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b. Nuclear Regulatory Commission

J. Nelson Grace, Regional Administrator

J. P. Stohr, Director, Division of Radiation Safety and Safeguards

R. D. Walker, Director, Division of Reactor Projects

G. R. Jenkins, Director, Enforcement and Investigation Coordination

B. W. Jones, Regional Counsel

D. M. Collins Chief, Emergency Preparedness and Radiological

Protection Branch

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C. M. Hosey, Chief, Facilities Radiation Protection Section

H. C. Dance, Chief, Reactor Projects Section 2A

R. E. Weddington, Radiation Specialist

C. W. Burger, Project Engineer

T. G. Lee, Radiation Specialist

L. Trocine, Enforcement Specialist

During the meeting, licensee personnel presented discussions of the sequence

of events leading up to the personnel exposure in question and detailed the

corrective steps taken and planned to preclude recurrence of such exposures.

Licensee representatives stated that their skin exposure calculations were

based on several very conservative assumptions and that there are now more

technically sound methods of determining skin dose than those used as the

basis of the regulations. The licensee maintained that it was unlikely that

an overexposure had occurred and that the employee's exposure was not safety

significant.

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NRC personnel expressed concern that the licensee's surveys of laundered

protective clothing had not been adequate to discover residual contamination

in the clothing that could cause significant personnel exposures. It was

further stated that the NRC technical staff would carefully review and

evaluate what had been presented by the licensee.

6. Staff Evaluation of Licensee Position Taken in the Enforcement

Conference

The licensee discussed in the Enforcemenc Conference on July 12, 1985, six

alternatives to the possibly conservative means of determining the licensee

employee's skin exposure used as the basis for submitting their LER of

July 5, 1985.

Three of the alternatives proposed discussed the technical basis for the

regulations in regard to at what tissue depth does the skin contain tissues

at risk for cancer inducement (i.e. , 7 mg/cm2 in the regulations as opposed

to 40 mg/cm2 or 125 mg/cm2 suggested by recent animal studies) and the l

appropriate exposure limit to the skin of the whole body (7.5 Rems / quarter l

over any one square centimeter of the skin as opposed to 50 Rems / year I

averaged over ten ' square centimeters in the proposed revision to 10 CFR 20). l

For regulatory purposes, the NRC continues to view skin exposure as that l

, dose which penetrates through a tissue equivalent layer of 7 mg/cm2 over any

one square centimeter with a corresponding quarterly exposure limit of

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7.5 Rems. However, the staff does consider the positions presented by the

licensee useful in viewing the safety significance of the event and agrees

that the exposure likely would produce no adverse health effects in the

individual.

The other three proposals presented by the licensee varied the assumptions

j regarding the circumstances of the exposure event. The licensee assumed

, that the Co-60 particle was transferred to the employee's skin as soon as he

i donned the protective clothing and did not move over more than a one square

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centimeter area of the skin during the two hour duration of- the exposure.

If the radioactive particle was not transferred immediately onto the

employee, a shorter exposure time (one hour for the statistical mean or

0.5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months based on work he had performed) would result in a calculated skin

exposure below the regulatory limit. Similarly, if the particle would have

moved during the two hour period over greater than a one square centimeter

area, no overexposure would have occurred. It is the NRC position that in

the absence of any objective evidence to the contrary, that~ conservative

assumptions are appropriate. However, the NRC agrees that the exposure

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would not likely produce any adverse health effects,

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ML20133Q284

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