ML20086F635

Responds to NRC 911030 Ltr Re Violations Noted in Insp Rept 50-274/91-01.Corrective Actions:Reactor Operations Committee Reevaluated Experiment O-13 to Address Beam Tube Movement & Health Physics Personnel Requirements

ML20086F635
Person / Time
Site:	U.S. Geological Survey
Issue date:	11/26/1991
From:	Danni Smith INTERIOR, DEPT. OF, GEOLOGICAL SURVEY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9112030340
Download: ML20086F635 (4)

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~ ,s im=====> E' li  ? O United States Deoartment r,f the Interior ENS-

- GEOLOGICat SURVEY ,

DOX 25046 M.S. _ 973 sum as DENVER FEDERAL CENTER DENVER, COLORADO 80225

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IN BtPLY ktf E2 TO:

DRANCH OF GEOCHEMISTRY November 26, 1991 Docket No. 50-274 License'No. R-113 U.S. Nuclear Regulatory Commission Document Control Deck-Washington, D.C. 20555

SUBJECT:

REPLY TO A NOTICE OF VIOLATION This letter is in response to your Notice of Violation dated October 30, 1991. The two violations identified are discussed below, Unreviewed Safetv Ouestion -

1. We do not feel that an unreviewed safety question existed with Experiment 0-13 since the Facility Safety Analysis Report (Hazards Summary Report) includes the potential release of an airborne activity equivaler.t to 10 curies of Cobalt-60. (Re:

Attached Section 8.3) The 0-13 argon hazard (0.045 curie) in significantly within this airborne radioactivity envelope. We acknowledge that this section of the Hazards Summary Report was not used by the safety committee during its initial review of the experiment; however, we believe that the safety envelope did exist to cover _the argon hazard. If this reasoning is incorrect, please explain why the attached Section 8.3 does not apply to Experiment 0-13. As stated in the notice of violation lett er, the radiological safety significance of Experiment 0-13 was minimal. If Section 8.3 of the Fazards Summary Report is

-not applicable, then we are concerned that there is no envelope for any airborne radioactivity releases except Argon-41 at our facility.

.2.- Despite our opinion that an unreviewed safety question did not exist, we have taken the action of informing the Reactor Operations Committee of the need for more rigorous and detailed safety evaluations. The provisions of 10 CFR 50.59 have been reviewed and discussed in detail by the Committee. In addition, the installation of the 8" beam tube and Experiment 0-13 have been re-evaluated by the committee _ since the enforcement conference.

3. Future experiment reviews will be performed with a more formal process of evaluating the associated hazards. The experiment authorization forms have been changed to force the documented evaluation of unreviewed safety questions in a more direct manner.

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'4.- We do not believe that we were out'of compliance in this matter;-however, the NRR acceptance of the revised Ar-41 hazard analysis was received on 10/9/91 and the Reactor

. Operations Committec re-evaluation of 0-13 was completed on 10/11/91. In any case, full compliance was certainly achieved by 10/11/91.

Inadenuate Procedqre for Experiment 0-13 -

1. We admit that the Experiment Authorization Form for Experiment 0-13 did not contain some r the concerns addressed by the Reactor Operations Cc.11ttee. The reason for'not stating that the beam tube plug must be moved with

-the overhead crane is that it is not reasonably possible to move it otherwise because of its weight. The reason for not stating that the beam tube must be moved slowly on the rails is that it cannot reasonably be moved quickly since it is projecting through about 24 feet of water and only moves about 1 foot, _Some radiological precautions and emergency response requirements for the facility are addressed elsewhere in facility requirements.

2. We have taken the corrective action of informing the staff and the Reactor Operations Committee of the need to be more detailed in the documentation of the Experiment Authorization forms. The Reactor: Operations Committee re-evaluated Experiment 0-13 and added a number of requirements and precautions to the authorization form. These address beam tube plug handling, beam tube movement, radiological surveys, access control, and health physics personnel requirements.

3. We believe that no further corrective actions are necessary.

4. Full compliance was achieved on 10/11/91.

We look forward to reaching final resolutions to these matters.

- - ,~ N b ,. Sincerely',g

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David B. Smith Reactor Administrator Subscribed and affirmed before me this 229Nay v of November, 1991, ar,, / bo

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Enclosure:

Section 8.3 of Hazards Summary Report Copy to:

U.S. Nuclear Regulatory Commission Regional Administrator 611 Ryan Plaza Drive, Suite 1000 Arlington, TX 76011 Tim DeBey, USGS N --

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g-13 where X(0,0,0) = Concentration at the building, pc/m ,

Q = Activity release rate Sc/sec.

II = Mean wind speed,1 msec ,

A = Cross sectional area of reactor room, 31.2 m .

Applying a reasonable duty cycle for the operation of the facility, that is 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> per day and 5 days per week of 1000-kw operation, yields an average argon-41 discharge rate of 6 5 -4 pc/sec (26)

-Q = 24 -7 (O. 513 x 10- 3) = 0. 913 x 10 Substitution of 0. 913 x 10' pc/sec for Q in equation (25) gives a value of X(0,0,0) = 5. 85 x 10 pc/m .

y 8. 3. HANDLING OF RADIOACTIVE ISOTOPES Because there can be intense radiation fields from radioactive isotopes produced by this reactor, reactor operations must be supervised by individuals trained in the detection and evaluation of radiological hazards.

For instance, activation calcolations indicate that the reactor is capable of producing an equilibriu.m concentration of approximately 10~ curies of cobalt-60 in the rotary specimen rack using only 20 rack positions. Since this production is distributed in 20 samples, the maximum amount of activity that can be withdrawn at one time is 5 x 10 curies. This constitutes such an intense source of radiation that manual handling is out of the question.

If such isotope production is attempted, the operating agency should obtain shielded isotope-handling equipment to reduce the radiation dosage to an acceptable level.

Remote handling equipment will not be necessary if the radioactivity of a sample is limited to a radiation level associated with 10 curies of cobalt-60.

From such a source removed from the reactor the dose rate to persons within 2 meters would be 58 mr/rnin. A person exposed to this dose rate for about 2 minutes would receive his weekly permissible dose of 100 mr. Nat urally,

i g.14 the' source lunit will depend upon the removal procedure used by the operating agency; however, such a limit should be made known tv the operating personnel for evaluating the potential exp >sures when removing a sample f rom the rotary c ampit rack. A radiation detector will need to be used to momtor the activity of the sample as it is removed from the reactor.

The maximum potential hazard f rom isotope production is from an accident in which this radioactivity is releasec. into the air of the reactor .

room Such an accident would regt.re a very spec:al set of conditions.

There would have t ' e either a spill during the removal f rom the reactor, or a reaction (perhaps chemical) of sufficient streng'h to disperse the j samples from the rack. In addition, the radioactive inple would have to

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be in gaseous form or of particle size sufficiently small to be dispersed

'$ as an at osol before a hazard could exist external to the reactor room. If such a set of conditions should occur, the radioactivity releas e d would still be les s than that assumed for the fuel cladding break Hence. In the unrestricted area outside the reactor room, the hazard associated v ith isotope production will be less than that produced by a fuel element failure.

This assumes that the r,dioactive isotope has opproximately the rame body organ uptake as that of the released fission products.

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8. 4. REACTOR POWER PULSING >

The reactor loading will be a maximum of 4. 9% 6k/h ($7. 00) exces s reactivity above . old. -! ean, c ritical and c ompact condition. A compact condition is a core loaded with all of the innermost lattice positions containing fuel and witn the uranium.?35 content (according to the metallurgical analysis of the fuel elements) progressively smaller with increasing distance from the core center. Thus, any rearrangement of the fuel will result in a lower excess reactivity.

Although the maximum exces s reactivity is 4. 9% 6k/k, the transient G control rod will be limited to 2.1% Sk/k. The reactivity that is controlled

- by the other rods, however, through a number of remote posatoi. ties, c ould

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