IR 05000073/1987002
| ML20237E445 | |
| Person / Time | |
|---|---|
| Site: | Vallecitos Nuclear Center |
| Issue date: | 11/24/1987 |
| From: | Russell J, Yuhas G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | |
| Shared Package | |
| ML20237E441 | List: |
| References | |
| 50-073-87-02, 50-73-87-2, NUDOCS 8712280339 | |
| Download: ML20237E445 (5) | |
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U. S. NUCLEAR REGULATORY COMMISSION
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REGION V
Report No. 50-73/87-02 Docket No. 50-73
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License No. R-33 Licensee: General Electric Company P. O. Box 460
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Pleasanton, California 94566 Facility Name:
Nuclear Test Reactor (NTR)
Inspection at:
Vallecitos Nuclear Center i
Inspection Conducted:
November 16, 1987
Inspector:
.r N / //
//./V-P ?
J. R ssell, Radiation Specialist Date' Signed Approved By:
M h/bV/f7 G.
P. Yuhas, Chief
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Date Signed Facilities Radiological Protection Section Summary:
Inspection on November 16, 1987 (Report No. 50-73/87-02).
Areas Inspected:
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This was a special, unannounced inspection to evaluate an overexposure of an operator during the third quarter of 1987.
Inspection procedures 30703, 83743, 90712 and 92700 were addressed.
Results:
No items of noncompliance were identified in the areas examined.
h2280339871201 G
ADOCK 05000073
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DETAILS 1.
Persons Contacted R. W. Darmitzel, Manager, Irradiation Processing Operation J. Cherb, Manager, Nuclear Safety and Quality Assurance j
l D. Smith, Manager, Nuclear Test Reactor
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All of the above individuals were present at the exit interview on November 16, 1987.
In addition to the individuals identified, the
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inspector met and held discussions with other members of the licensee's
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staff.
2.
Initial Licensee Report l
By letter dated October 30, 1987, and received at the Region V office on November 2, 1987, the licensee made a report in accordance with 10 CFR 20.405, Reports of Overexposure and Excessive Levels and Concentrations, of an overexposure of an operator at the Vallecitos Nuclear Center (VNC),
Nuclear Test Reactor (NTR), to 1,530 mrem in the third quarter of 1987.
The letter stated that the operator received a whole-body dose of 880 mrem, gamma, and 650 mrem, neutron, without having documented a review of I
the individual's exposure history on a form NRC-4, or equivalent, as
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required by 10 CFR 20.101, Radiation Dose Standards for Individuals in
l Restricted Areas.
This was discovered on October 7, 1987, during review of a routine report from the licensee's dosimetry vendor.
The letter stated further that the review had been performed but that no exposure
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extension was issued as the individual's exposure was not expected to exceed 1250 mrem.
This was due to underestimation of the neutron
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contribution to the whole-body dose.
3.
NRC On-site Followup A regionally based Radiation Specialist reported to the site on November 16, 1987, to review the event.
Based on a review of licensee records and procedures, discussions with personnel and independent measurements made j
by the inspector, the following was revealed.
l The Dosimetry Report from the licensee's dosimetry vendor for the third quarter of 1987 indicated cumulative whole body deep doses of 1530, 1840, 909, 750 and 1540 mrem for the five individuals that work at the NTR with 650, 650, 310, 270 and 600 mrem, respectively, due to neutron dose.
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form ATPE-699, Request for Special Planned Exposure, and computer generated equivalents of form NRC-4s were available and completed in accordance with VNC Safety Standard 5.2.2, Special Planned Exposure, for j
the individuals that received 1840 and 1540 mrem whicn authorized l
quarterly exposures of 1600 and 1500 mrem, respectively.
No completed
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documents were available for the individual that received 1530 mrem.
The inspector interviewed the NTR manager relative to the event.
The l
l manager stated that'the NTR is used primarily for neurography and has a staff of five peopl?.
The individuals try to rotate the work of sample L_-____-_--__-=_-_-__------------
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preparation, change out and reactor operation as much as possible but there had been an unusually large workload during the third quarter which resulted in increased exposures for the period, particularly during September.
He had reviewed personnel exposures in September and had authorized two extensions.
The manager stated that his review of the anticipated exposure for the individual.in question had been in error due to underestimation of the associated neutron exposure and that he had not
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authorized an exposure extension as he did not anticipate one being l
necessary.
The manager was familiar with the gamma and neutron dose i
rates in the control room and the north and south neurography rooms.
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NTR personnel gamma exposures are tracked by self reading pocket dosimeters and are recorded periodically with an estimate of the associated neutron exposure on a bar chart maintained in the control room in accordance with Standard Operating Procedure 7.5, Radiation Exposure and Control.
The procedure stated that neutron exposures are typically 30% of the penetrating gamma exposure and required a 30%
increase of the gamma exposure to allow for the additional neutron dose.
It is noted that direct correlation of gamma to neutron exposure is improper as the gamma exposure rates in the facility are fairly constant when the reactor is operating but that neutron exposure rates to personnel, particularly in the control room, are a function of the time the shutter is open to the south cell during neurography.
The south cell is adjacent to the control room and is entered through a shield door.
Licensee surveys of the control room, with the south cell shutter open, indicated dose rates at the control console of 4 mR/hr gamma and 3.5 mrem /hr neutron.
Comparative measurements were made by the inspector with a Nuclear Research Corporation Rem-Rad meter, serial number NP581701, calibrated on 30 September 1987 and due for calibration on 30 September 1988, which indicated a comparable neutron dose rate.
Dose rates with the shutter closed were <0.2 mrem /hr neutron as measured by the inspector.
The reactor cell is not accessible during reactor operation and the south cell is not accessible during operation when the shutter is open.
Licensee surveys indicate dose rates of 7 mR/hr gamma and 10 mrem /hr neutron in typically occupied areas of the south cell with the shutter closed.
The north room is occasionally occupied during operation and when the shutter is open.
The typically occupied area of the north room was <0.2 mrem /hr neutron with the shutter closed and approximately 0.8 mrem /hr with the shutter open.
The gamma dose rate, as measured with the licensees Technical Associates CP-5, serial number 11556, indicated approximately 0.5 mrem /hr gamma at the typically occupied location.
Neutron measurements made with the licensees Eberline PNR-4, serial number 3237, compared well with those made with the inspector's instrument.
The inspector interviewed the operator in question relative to the event.
The individual had worked at NTR for a number of years and was familiar with expected dose rates and procedures.
The individual stated that he had participated in no unusual operation during the third quarter which could have contributed to increased exposure and believed that he had picked up most of his dose during routine operations sitting at the control console and changing samples in the south cell.
He noted that the work load had been particularly heavy during the third quarter, particularly during September.
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Tiie inspector reviewed. Incident Investigation 87-5, Quarterly Exposure Exceeding 1.25 Rem Without Form 699: Exposures Exceeding Form 699
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l Approvals, and the responses thereto from the NTR manager.
The report
appeared to satisfy the' requirements of Technical Specification 6.2, Independent Reviews.
The corrective actions instituted to prevent-recurrence were:
Change the reading frequency of the neutron albedo dosimeters.for
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the NTR operators from quarterly to monthly.
- l Increase the frequency for entering pocket dosimeter readings on the l
control: room chart to a minimum of once per week and use a factor of 50% (rather than 30%) to estimate the neutron component ^of exposure.
Revise Standard Operating Procedure 7.5 to reflect these changes.
NRC regulation 10 CFR 20.101, Radiation Dose Standards for Individuals in Restricted Areas, states in part:
"(a) In accordance with the provisions of S 20.102(a), and except as provided in paragraph (b).of this section, no licensee shall-
- possess, use, or 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 dose in excess of the standards specified in the following table:
REMS P.ER CALENDAR QUARTER
"1.
Whole body; head and trunk;. active blood-forming organs; lens of eyes; or gonads..........
1%
"(b) A licensee may permit an individual in a. restricted area to' receive a total occupational dose to the whole body greater than that permitted under paragraph (a) of this section, provided:
"(1) During any calendar quarter the total occupational dose to the whole body shall not exceed 3 rems; and'
"(2) The dose to the whole body, when auded to the accumulated occupational dose'to the whole body, shall not exceed 5 (N-18)
rems where "N" equals the individual's age'in years at'his last i
birthday; and
"(3) The licensee has determined the individual's accumulated occupational dose to the whole body on Form NRC-4, or.on.a clear and legible record containing all the information required in that form; and has otherwise complied with the requirements of S 20.102.
As used in paragraph (b), " Dose-to'
the whole body" shall be deemed to. include any dose to the
- whole body, gonads, active blood-forming organs, head-and trunk, or lens' of eye."
NRC regulation 10 CFR 20.201, Surveys, states:
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"b) Each licensee shall make or cause to be made such surveys as=(1) may be necessary for the licensee to comply with the regulations in this part, and (2) are reasonable under the circumstances to evaluate the extent of radiation hazards that may be present."
rnd further defines the term " survey" as:
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"(a) As used in the regulations in this part, " survey" means an evaluation of the radiation hazardsfincident to the production, use, release, disposal, or presence of radioactive materials or other sources of radiation _under a specific set of conditions. When appropriate, such evaluation includes a-physical. survey of the location of materials and equipment, and measurements. of. levels of radiation or concentrations of radioactive material present.".
The exposure of an individual to_1.530 rem in the third quarter of 1987 without completion of Form NRC-4, or equivalent, and the failure to perform surveys 'as necessary to comply with' the whole body dose limit are apparent violations of 10 CFR 20.101 and 20.201.
However, 10 CFR Part 2, Appendix C, Paragraph V, Enforcement Actions, provides that_the NRC will-l.
not generally issue a notice of violation for a violation if (1) it was identified by.the licensee; (2) it fits i_n Severity Level IV or V;.(3) it was reported; if required; (4) it was or will be corrected, including measures to prevent recurrence, within a reasonable time; and (5) it was not a violation that could reasonably be expected to have been prevented by the licensee's corrective action for a: previous violation.
This event was identified by the licensee; it would.normally be-considered of Severity Level IV.- as defined in Supplement IV. of' 10 CFR 2, Appendix C; it was properly reported by the licensee; the event was evaluated and corrective action was instituted which it appears will be effective to prevent recurrence; and it could not reasonably have been expected that the event could have been prevented by licensee corrective action for previous violations.
Therefore, no notice of violation will be issued for this event.
4.
Exit Interview The inspector met with the licensee representatives, denoted in paragraph 1., at the conclusion of the inspection on November 16, 1987.
The scope and findings of the inspection were summarized.