ML20210E447

Forwards RAI Re 990419 Application Request for Registration of Model 1 Irradiator & Model GS-42 Seal Source.Response Requested within Thirty Days of Date of Ltr

ML20210E447
Person / Time
Issue date:	07/26/1999
From:	Jankovich J NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS)
To:	Stein R AFFILIATION NOT ASSIGNED
References
SSD, NUDOCS 9907280224
Download: ML20210E447 (17)

Text

l pwou O 4 UNITED STATES

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't NUCLEAR REGULATORY COMMISSION WASHINGTON. D.C. 20665-0001 O

, g , ,o July 26, 1999 Mr. Russell N. Stein Vice President GrayStar, Inc.

Mt. Arlington Corporate Center Suite 103 200 Valley Road Mt. Arlington, NJ 07856

Dear Mr. Stein:

This letter is in response to your application dated April 19,1999, requesting registration of the Model 1 Irradiator and the Model GS-42 sealed source. We are in the process of evaluating your request. We have identified areas where additionalinformation or clarification of your application is needed as described in the Enclosure. In order to continue our evaluation, you must address these issues.

Please submit the requested information within thirty days of the date of this letter, in case you need additional time to respond, please let us know, in writing, when you will be able to respond. We need this information for scheduling our activities. If we have not received complete information within the designated time frame, we will consider your application as having been abandoned by you. This is without prejudice to the resubmission of a complete application.

Please also note that we have conducted the evaluation of your application as a Category ll irradiator. Your design fits the definition in ANSI N43.10: "[a] controlled human access irradiator in which the sealed source is contained in a dry container constructed of solid materials, and the sealed source is fully shielded when not in use; the sealed source is exposed within a radiation volume that is maintained inaccessible during use by an entry control system."

A number of questions in the Enclosure refer to the provisions of 10 CFR 36, Licenses and  !

Radiation Safety Requirements for Irradiators which states that "[t]he regulations in this part apply to panoramic irradiators that have either dry or wet storage of the radioactive sealed sources and to underwater irradiators in which both the source and the product being irradiated

are under water. Irradiators whose dose rates exceed 5 grays (500 rads) per hour at 1 meter l from the radioactive sealed sources in air or in water, as applicable for the irradiator type, are

! covered by this part." Your design is within the scope of this regulation. Our questions address those aspects of the design which apply generically to all locations where you may want to install the irradiator and, therefore, should be resolved at this time.

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Mr. Russell N. Stain Your application includes engineering drawings that are marked as proprietary. Regarding the proprietary notes, please either (a) provide a statement that the notes do not apply to the drawings  ;

which are part of your application, or (b) if you wish to keep certain information proprietary, be  !

aware that you may request that certain portions of your submittal to NRC be withheld from public disclosure as proprietary information. To do this, you must execute an affidavit a specified in 10 ,

CFR 2.790. You must list all portions that you wish to be held proprietary, along with your j reasoning as to why that is appropriate. While it is allowable, please refrain from ilubmitting proprietary information in support of a registration unless necessary. Keep in m!ad that all registration certificates in the Sealed Source and Device Registry, and all NRC licenses are considered to be in the public domain, therefore, they may be viewed by any member of the public who requests to see them.

A number of statements in the application are not relevant to the device registration. Specifically, on pages 7 and 29 you discuss ownership of the irradiators. You discuss a lease agreement between GrayStar and the user on pages 29 and 30. Page 9 of the application discusses a collective escrow account you intend to setup for moving and decommissioning the irradiators. 1 Since this information is not needed for, and is outside the scope of, the safety evaluation of your application, we did not review them. You are free to pursue these arrangements independently of the sealed source and device registration process.

If you have any questions, please contact me at (301) 415-7904 or Mr. Frederick C. Sturz at (301) 415-7273.

Sincerely, r

A John P. Jankovich, Ph.D., Sr. Engineer Materials Safety and Inspection Branch Division of Industrial and Medical Nuclear Safety Office of Nuclear Material Safety and Safeguards

Enclosure:

as stated Distribution: l IMNS r/f SSD-99-27 NE01h T. Kobetz, SFP0 .

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CSantos/RES RShane/IMNS DOCUMENT NAME: G:\Jankovich\def. letter To receive e copy of this document, indicate in the box: "C" = Copy without attachment / enclosure "E" = Copy with attachment / enclosure j

'N' = No copy OFFICE IMNS ,.,, f IMNS /J n . &

NAME JJankovich/jj g I[ FStudM)

DATE 07/ SF/99 V 07/ % /9'9 OFFICIAL RECORD COPY

1 Enclosure to letter, Mr. Russell N. Stein, GrayStar, Inc.

Request for Additionalinformation I GrayStar Model 1 Irradiator and Model GS-42 Sources l 1

For sealed sources and devices, the applicable guidance " Consolidated Guidance About Materials Licenses: Applications for Sealed Source and Device Evaluation and Registration,"

NUREG-1556, Vol. 3, dated July 1998, specifies that construction and prototype testing must be described in sufficient detail "to allow the reviewer to fully understand the construction and 3 operation of the product and its components and safety features and to evaluate the product's i safety and integrity." Accordingly, we need additionalinformation regarding the design and 1 construction of the GrayStar Model 1 irradiator and the Model GS-42 sources which were submitted for approvalin the application of GrayStar, Inc., dated April 19,1999.

Source Desian:

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1. During testing in accordance with ANSI 43.6-1997, three of the eight prototype sources failed. Your solution was to weld the exterior seal plug. The outer encapsulation is intended to be the final barrier for a doubly encapsulated source. Please explain how your source can be a " doubly encapsulated" sealed source as defined in 10 CFR 36.2:

" Doubly encapsulated sealed source means a sealed source in which the radioactive material is sealed within a capsule and that capsule is sealed within another capsule."

Describe your investigation to determine why the internal encapsulation failed and how it could be corrected?

2. The provisions of 10 CFR 36.21(a)(3) require that the radioactive material be as nondispersible as practical. What criteria were used to determine the form of the Cs-1377 Did you consider another chemical form or processing method (e.g. turning the Cs-137 into glass beads) to reduce nondispersibility and solubility? Please note that solubility should also be considered because the radioactive material could come into contact with moisture should the source containment fail.

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3. Section 4.1.3 of ANSI 43.6-1997 specifies the activity of materials to be used in sealed sources stating that "[s]ources containing more than the maximum activity shall be subject to further evaluation of the specific usage and design." The maximum activity, j given in Table 3 of the Standard, is 30 Ci for Cs-137 in the form you propose to use and 1 300 Clif non-leachable and non-reactive. In the GrayStar irradiator the maximum activity level of 3x108 Ci is divided into 64 sources, i.e. approximately 46.9x10 Ci per  ;

source. Please delineate what "further evaluation of the specific usage and design" you have performed regarding the requirements of the Standard for such activity.

Source Construction  ;

4. On page 3 of Exhibit 3, the fourth and fifth paragraphs discuss the loading of the prototype source. Several differences between the procedure for loading the prototype  !

and the production sources were referenced. For example, the annuhm of the test sources was purged with nitrogen to remove residual traces of heliu .. a.id the production sources will not be purged leaving the annulus with ambient atmosphere.

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Evaluate the impact this would have on the validity of the ANSI N43.6-1997 tests?

Please evaluate the validity of the tests to the final design.

5. Please provide the maximum activity of the Model GS-42 sealed source, indicating the percent error expected. In order to differentiate between the two sources, please add distinguishing designations such as GS-42L for the long source and GS-42S for the short source.

6. How will the activity and assay date for each source be determined and documented when transferring the device to the customer?

7. NUREG-1556, Vol. 3, Section 10.5, specifies that "[i]n addition to testing with an ANSI or ISO standard, the applicant may need to perform additional testing to verify that the i source will withstand the conditions of use." Since no historical data is available for the sealplugs you intend to use, please indicate, for the 60-year working life, how the seal 4 plugs maintain sealing properties with metallic silver on the seats. I

8. For the seal plug, specify the maximum allowable torque with an acceptable range of ,

values. The application shows a nominal value of 100 lb-ft. But, as shown in Page 9 of 95 in Exhibit 3, the applied torques vary greatly from 120 lb-ft to 175 lb-ft for the tested units. Please also indicate what effects the torque values may have on how the silver 1 acts as a lubricant and sealant with the higher torque and how the lower torque value would ensure a leak free condition. Please also indicate any effects that the welding of the outer seal plug could have on the integrity of the silver sealant.

Source Testina

9. A discrepancy appears to be in the results reported for the thermal shock tests. Exhibit 3 (Prototype Testing - Source) Day 5 describes the results of additional thermal shock tests which were performed on an inner and an outer fill endcap. It states that "The results of the integrity check (TRS-011) indicated that there was a leak on the inner seal and not on the outer seal." However,in Attachment 11-3 Page 91 of 95 of Exhibit 3, entitled " Test Record End Cap / Seal Plug Helium Leak Test" it indicates that the outer end cap / seal plug assembly's helium test results were unacceptable while the inner end cap / seal plug assembly helium test results were acceptable. Resolve this discrepancy j and identify the exact location of the leakage.

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10. In procedure TRS-008 for vibration test, the sources were tested in only two l perpendicular axis instead of three perpendicular axis vibrations as specified in ANSI N- '

43.6, Section 7.5.2 for Class 2 sources. Please justify why testing in all three directions is nit necessary.

11. In procedure TRS-006, for external pressure test, you tested with a pressure value of  ;

14.71 kN/m2 in instead of 25 kN/m2 as specified in ANSI N-43.6-1997 for Class 3 I sources. Please explain the discrepancy. Please provide test data or analysis for external pressure of 25 kN/m2, 2

12. ANSl43.6-1997 describes temperature, impact, vibration, and puncture tests which can be performed on various sources. This standards requires that these tests be performed at ambient temperature. In your application you state that since the GS-42 will be operating at temperatures between 200 C and 400*C, the test parameters used in your prototype testing were changed to try to simulate the actual operating conditions of the source tubes. Exhibit 3 (Prototype Testing - Source) describes temperature correction factor calculations used to determine the load multiplication factors needed to apply during the ambient temperature tests to simulate the loads and stresses that would occur at elevated temperatures. For example the prototype test loads for the impact test was increased from 2 kg to 3.4 kg (i.e. 2kg x 1.7 = 3.4 kg) due to a temperature correction factor of 1.7 calculated for 750 F based on yield strength of the stainless steel material.

In the ANSI external pressure test the sources are to be pressurized at 2MPa (290 psi).

However, in your prototype testing the external pressure test was performed using 2.24 MPa (325 psi). This ratio gives a temperature correction factor of 1.12 (i.e.

2.24MPa/2.0MPa = 1.12). This value does not correspond to any of the temperature correction factors listed on page 2 of 31 of Exhibii 3 for the External Pressure Multiplication Factor. Please show the basis for the temperature correction factor of 1.12 used in external pressure test.

Corrosion

13. Source integrity of irradiators is required in 10 CFR Part 36. NUREG-1556, Vol. 3, Section 10.3 (Construction of the Product) also states that "the reviewer must evaluate how the product is constructed and evaluate it's integrity." Therefore, please address the following issues: CsCl encapsulated in 316L stainless steel has been selected as  ;

the source for this application. Chlorides are well known to cause pitting in stainless  !

steels. Please show that the chlorides will not form pits in the stainless steel encapsulations during (a) the procedure by which CsCI is placed into the inner source tube and (b) operation of the irradiator for a projected life of 60 years.

14. Numerous crevices exist on the inside surface of the inner and outer encapsulation l tubes. Please show that crevice corrosion could not occur in these areas. i

15. The fabricatior process calls for the encapsulation tubes to be welded. Stress corrosion cracking can also occur in stainless steels in chloride solutions. Please show that stress corrosion cracking will not occur in either the inner or outer encapsulation tube l due to weid residual stresses and any applied stresses. l

16. What effects do the source impurities listed in Exhibit 2 (Chemical Composition of Source Material- Cesium Chloride) have on the pitting, crevice, and stress corrosion cracking mechanisms?

17. What effect will the CcCl and its impurities listed in Exhibit 2 (Chemical Composition of Source Material- Cesium Chloride) have on the silver used as a sealant for the plugs?

, 18. Page 12 of 38 in the application states that "[d]ue to the indefinite operational life of the

! unit, it is assumed that certain parts might fuse due to corrosion over very long periods i of time." Please elaborate on this statement. What type of corrosion could occur and

! what effect would it have on the unit? What parts are anticipated to corrode and fuse l together? In what timeframe is this expected to happen?

19. Page 8 of 38 states as part of the conditions of use for the irradiator"the unit should not be installed where the air quality is excessively corrosive in nature". Please elaborate l on this statement. Quantify the conditions described as " excessively corrosive."

Source Fabrication

20. The description of the source and rack on page 10 paragraph 6 states the following:

"One end is made of blind endcaps. The other end has fill endcaps which allow for the introduction of CsCl after the encapsulations have been fully welded and inspected. This method is referred to as Grayfill (tm)."

Please describe in detail this Grayfill (tm) method.

21. In Exhibit 8 (Source and Rack Drawings) Drawing Nos. AAl-403 and AAl-404, Note 1 states tnat "[t]he inner source tube is to be filled with radioactive cesium chloride in accoidance with Gray

• Star Procedure No. XXXX."

Identify this procedure number and describe it in detail, is this identical to the Grayfill (tm) method referred to earlier?

22. Exhibit 3 (Prototype Testing - Source) paragraph 4 of the section on Test Source Preparation describes the following possible way that CsCl could be loaded into the encapsulation:

"In production, this might be performed through an evaporative process where CsCl is introduced into the inner encapsulation dissolved in water and subsequently dried. To assure dryness of the test specimens, the encapsulations were placed in an oven and heated for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> at 120 C prior to being sealed."

Exactly what procedure will be used to place the CsClin the encapsulations? If any type of evaporative process is umi, any water left inside the tubes could lead to pitting of both the inner and outer encapsulation. Please show that the drying procedure to be used will successfully remove all water in both the inner and outer tubes especially in locations such as crevices.

23. What atmosphere and pressure will exist in the annulus between the inner and outer encapsulation? Paragraph 5 of Exhibit 3 (Prototype Testing - Source) of the section on Test Source Preparation ir.dicates that the annulus will likely contain ambient atmosphere. What effect would this environment have on the integrity of both the inner and outer encapsulation? For example, if the inner encapsulation failed, the CsCI could F

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be released into the annulus region. If any moisture exists in this area, chloride could form pits in the outer stainless steel encapsulation.

24.~ The drawings in Exhibit 8 (Source and Rack Drawings) show the welds for the blind endcaps and fill endcaps for both the inner and outer source tube. What non-destructive examinations will be dono on all the welds associated with sealing the inner and outer encapsulation? The drawings indicate that liquid penetrant, visual and He leak testing will be done on these welds. Will all three types of examinations be done on each weld? Please also specify what standards will be used.

25. The last paragraph on page 10 states that "the outer seal plug is also welded with a seal

! weld after both seal plugs are inserted." What welding procedure will be used? What

! non-destructive examination methods will be performed after welding this outer seal l plug? Please specify the applicable standards. These seal plugs have a metallic silver plating which is used as a seal. What effects will the silver have on the weld?

i 26. In Exhibit 8 (Source and Rack Drawings) Drawing No. AAl-409, Note 7 states that l

" Stress relief may be performed during the forming process in accordance with ASTM A269 supplementary requirement S1. Mechanical straightening is permissible after stress relief." However, ASTM A269 S1 states that "No mechanical straightening is l permitted after the stress-relief treatment." How will this remain in accordance with ASTM A269 requirements?

27. Exhibit 9 (Device Drawings) Drawings 303100 Sheets 1 and 2 indicate that segments of the outer cuff will be welded. What welding procedures will be used for these welds?

Chemical Comoosition of Radioactive Material- Cesium Chloride

28. Exhibit 2 (Chemical Composition of Source Material- Cesium Chloride) lists possible impurities which could be present in addition to CsClin the source material. This section also describes potential problems which could be caused by the source material l

including any of its impurities and how the GS-42 encapsulation would react. At the end of this section 17 references are listed. Please provide cross indexing between the statements in the text and the references in Exhibit 2, indicating in the narrative correspondence to the 17 references listed.

l B. Device Desian

29. NUREG 1556, Vol.3, Section 10.3, specifies that the description of the product "should be sufficient to allow the reviewer to fully understand the construction and operation."

Pages 1-38 of the application present the description of the design; however, this section of the application is not sufficiently cross-referenced to the technical drawings to make clear to the reader the construction and operation of the irradiator. Clarity is also needed for permanent records. Therefore, please modify your application pages 1-38 to

, include references to specific drawings and procedures included in the attached Exhibits.

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) 50. In Page 7 of 38, your application claimed, without supporting documents, that "[t]he unit i is designed to survive a 3.3g horizontal acceleration during an earthquake without losing l safety integrity." Provide the unit's seismic capacity and its calculation including modeling and boundary conditions when the source / door is in the lower, middle, and upper position. The three axes of earthquake (two horizontal earthquakes of same magnitude and one vertical earthquake of 2/3 of horizontal earthquake magnitude) should be applied simultaneously.

In your response, please also address, in addition to description of structural design for seismic protection, the mechanism to maintain the integrity between the hydraulic lug and the bottom yoke assembly during the earthquake as to be calculated above.

For similar analyses regarding earthquakes, please refer to NRC Standard Review Plan (SRP), Sections 2.5.1 through 2.5.5,3.7.1 through 3.7.4, and 3.8.1 through 3.8.5. They are available at http://nrr10.nrc.cov/sro/sro.htm or in NRC report NUREG-800,

" Standard Review Plan for Review of Safety Analysis Reports for Nuclear Power Plants." You may use these documents as guidelines.

31. In Page 31 of 38, your application stated that "the site is prepared with a suitable foundation for the local environment." The local codes differ from each other, therefore, provide the bounding parameters for the foundation mat and soil conditions and their seismic capacities so that the each user would not need to duplicate issues that are common regarding the foundation adequacy.

Provide the anchoring systems between the foundation mat and the unit as well as their seismic c:apacities for the complete unit.

In Page 27 of 38, your application stated that there is a 0.055 R/hr flux out the bottom of the unit when the door / source is in its down position. For the 60-year working life, this flux should be considered for its effect on the foundation mat and anchoring systems.

32. For consideration of natural phenomenon such as high wind / tornado, provide the unit's impact, puncture, and explosion capacities and their calculations. Under the influence j of tornado, there is the pressure drop outside the unit and, consequently, the unit might i experience the internal over-pressurization. Tornado missiles can penetrate the building and hit the unit. Therefore, the missile barriers might be considered. For similar analyses regarding wind / tornados, please refer to NRC SRP 3.3.1,3.3.2,3.5.2, and 3.5.3. The referenced documents are available at http://nrr10.nrc.aov/sro/sro.htm or in NRC report NUREG-800," Standard Review Plan for Review of Safety Analysis Reports for Nuclear Power Plants." You may use these documents as guidelines.

33. Provide the hydraulic system reliability data including prototype test, potential models, ,

historical experience in similar type of use, operating conditions, eic. Also, the following information should be provided: preventive and corrective maintenance actions and their schedules, appropriate filtration, relief valves, operating temperatures and pressures.

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l I In Page 18 of 38, your application stated that "[s]ince the door / source's weight never ,

changes, the setting of this over-pressure will be quite sensitive." Specify the threshold

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pressure and the tolerance to lower the door / source to the down position.  !

34. Describe the principles of operation of the uninterruptable power source. List the equipment, its capacity, relevant technical specifications, and maintenance requirements.

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35. NUREG 1556 Volume.3 Section 10.3 states that " Applicants need to describe construction aspects of the product including components of the product, materials of construction, dimensions ...." The application does not specify exactly what materials are to be used in the construction of this device. Drawings in Exhibit 9 (Device Drawings) note that the material used to construct certain parts will be a " mild steel" unless otherwise noted. Examples of this are listed below (note that this is not a comprehensive list):

Drawing 303100 sheets 1,2 and 3 - Drawings of the Lower Inner Column Drawing 304100 sheets 1,2 and 3 - Drawings of the Upper Inner Column Specifically, what type and grade of steel will be used? Please provide detailed specifications (ASTM or other relevant standards) for each of the materials that will be used to construct the device. This should include any and all concrete (e.g. in the upper inner column) as well as steel components.

l 36.

Clarify the following issues regarding the technical drawings in Exhibit 8:

. 1. In Note 3 of Dwg. No. AAl-403 and -404, specify the nomina! torque value and its tolerance to break the shank.

2. In Note 3 of Dwg. No. AAl-403 snd -404, provide TRS-025.

3. In Note 7 of Dwg. No. AAl-405, the trefoil is in the fill end. However, based on the AAl-403, it is in the blind end. Clarify this discrepancy. ,

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4. In Note 14 of Dwg. No. AAl-405, clarify the statement "[t]he threads and conical seal shall be reworked in accordance with the TRS-022." TRS-022 is not included in your application.

5. . in Note 15 of Dwg. No. AAl 405, the estimated nominal weight of the finished assembly is 12 lbs. Based on the weights specified in the block, it is 11.5 lbs (0.7 + 0.8 + 4.9 + 5.3 = 11.5 lbs). Clarify this discrepancy.

6. In Note 14 of Dwg. No. AAl-408, the estimated nominal weight of the finished

, assembly is 5 lbs. Based on the weights specified in the block, it is 4.6 lbs (0.4 +

0.8 + 3.4 = 4.6 lbs). Clarify this discrepancy.

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7. In Note 13 of Dwg. No. AAl-408, clarify the statement "The threads and conical l seal shall be reworked in accordance with the TRS-023." TRS-023 is not I included in your application.

8. In Note 5 of Dwg. No. AAl-413, why are the P/N and S/N inside the fill end?

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9. In Note 5 of Dwg. No. AAl-414, why are the S/N and P/N inside the blind end?

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Radiation Protection

37. In order for us determine that the radiation protection measures are adequate, some additionalinformation is needed. Section 10.6 of NUREG 1556, Vol. 3, provides guidelines for determining the radiation profiles for a device. Your application provides radiation profiles in Exhibit 4. Please provide the name of the computer software used to determine the radiation profiles. It is stated on page 26 of the application that "there are many assumptions built into the model". Please provide specific information detailing these assumptions, and the technical basis for their selection. Also, please provide detailed sample calculations, including input parameters, so that we may verify them.

It is noted in Exhibit 4 that neither the calculations nor the software have been validated under the GrayStar QA plan. How do you plan to verify and validate the software, and its output?

38. Please provide the following dose rate calculations to demonstrate compliance with the provisions of 10 CFR 36.25:

1. Calculations for the area surrounding the chamber inside the cuff, when the sources are in the down position, or in transit.

2. Calculations for the inside of the product chamber. What are the expected dose rates within the product chamber? Provide data for the geometric center of the empty chamber, the center of each side, and the center of the top and bottom when the sources are in the fully exposed position in order to verify the shielding calculations. Also provide data at the same points when a typical product is loaded into the chamber.

3. Calculations for the dose rates at the bottom of the unit, as discussed on page 27 of your application. Also, please provide a drawing of the footing for the unit, demonstrating the inaccessibility of the area under the unit, when it is installed above ground.

4. Calculations for dose rates on top of the unit with the sources in the up, down, and in-transit positions.

5. Page 16 of your application states that the unit can be operated with the outer security doors open, thus providing the visualindication of the position of the sources. Please provide the basis for allowing the unit to be operated with the outer security doors open. As part of this process, please provide dose rate calculations, including scatter and streaming, with the sources in transit (25%,

50%,75% and full height), and the outer security doors open.

39. Using the drawings submitted with the application, it is difficult to visualize the shielding arrangement and the measures incorporated to reduce streaming. Furthermore, we understand that the drawings do not indicate all the shielding features incorporated, e.g.

Drawing No. 302-200 does not show the stepping that we understand is present 8

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between parts of the retainer plug. Please submit separate drawings, dedicated to i shielding calculations, showing allimportant components and features of the device I shielding, and their relationship to one another. The drawings should specifically show the relationship of the streaming blocks, " minor shielding components", Graystop, and I the 2" shroud, to the door / source, including dimensions, tolerances, and clearances.

Please include shielding calculations with the source in the up, down, and in-transit l positions to demonstrate their effectiveness. Also, please show any penetrations in the I shielding, and the duct work and wiring conduits in the upper inner column. As a guide,  ;

you may use NUREG 1556 Vol. 6, Section 8.9.3. '

40. Please describe the air ventilation / filtration system referenced on page 20 of the application, and represented in Drawing No. 309-100. Please include in this description:

1. how the two ventilation systems interact with each other,

2. the technical basis for selecting a positive pressure (blower) design, as opposed to a negative pressure design,

3. the expected physical form / particle size of any leaking radioactive material,

4. the efficiency of the system for collecting leaking source material, including the filter efficiency, and

5. the adequacy of the 1000 CFM flow rate.

i Also, please consider in your analysis that Drawing No. 309-100 seems to indicate that the air primarily circulates between the outer cuff and the outer wall of the door / source. i The air flow does not appear to necessarily pass over the sources. Clarify the airflow l over the sources as well as in the wall of the door / source which are not equipped with I the air intake and outlet vents.

41. Please provide calculations for ozone production in the chamber, as mentioned on page 20 of your application, and the technical basis for determining that the ventilation system is adequate to assure safety to the user.

42. 10 CFR 36.59 requires that each source be tested for leakage of radioactive material.

In addition,10 CFR 36.13(e) states that "[t]he applicant must include . . the method of detecting leaking sources required by 36.59, including the sensitivity of the method."

Exhibit 10 specifies wipe sampling of a point on the interface of the lower inner column and the door / shield. Please demonstrate that the selection of the wipe sample location or locations will provide a sample that is adequately sensitive to detect a leak in any of the sources. In demonstrating this, assume that water may be routinely used to clean the irradiation chamber at some facilities.

If the proposed leak test methods fail to show a level of sensitivity to detect a leaking source, submit a procedure for leak testing each source, which samples the points at which material leaking from the source is likely to accumulate it is possible this will involve sampling from more than one location in order to have comparable sensitivity for all sources.

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Your submitted leak test procedures use the level of 1 mR/hr as a decision level on whether to send the collected samples to a lab for analysis. Please demonstrate how the 1 mR/hr decision levelis adequate to protect the health and safety of the public.

Please include in this demonstration, the amount of radioactive material that would have leaked from the sources in order to reach the 1 mR/hr level on a hand held survey instrument for the filter leak test, the smear leak test, and the liquid sampling test.

43. 10 CFR 36.23(c) requires that a radiation monitor be provided to detect the presence of j high radiation levels. Please provide a description of the automated dosimetry system,  ;

including '

1. principles of operation of the system,

2. description of the ion chamber detectors,

3. the range of dose rates detectable, and i'

4. how the system is integrated with personnel access door locks.

44. On page 23, the application states that "High Radiation Area Within" will be clearly marked on the visible portion of the door source.10 CFR 36.23(g) requires that irradiators be posted in accordance with 10 CFR 20.1902. The area within the chamber meets the definition of a "very high radiation area" and should be posted as such.

To meet the requirements of 10 CFR 20.1902(e) the irradiator must be conspicuously posted with a signs bearing the radiation symbol and the words " CAUTION, RADIOACTIVE MATERIAL (S)'" or " DANGER, RADIOACTIVE MATERIAL (S)." both at .

the level at which product is loaded into the irradiation chamber and at the level at which j the sources are stored in the down position. Exhibit 11 of your application discusses j only one such sign, and it is located on the outside of the outer security door. When the l door that is opened during operations, the sign is not conspicuous. Describe the additional labels that will be used so that the irradiator meets the requirements of 10 CFR 20.1902(e).

45. As discussed in item 10.8 of NUREG-1556, Vol. 3, please submit evaluations of the dose received by individuals servicing the irradiator to show compliance with 10 CFR Part 20. These evaluations should include, at a minimum, the following operations:

1. Installation of the device;

2. Inspection of wiring;

'3. Servicing of the wiring;

4. Removal of debris from the interior of the cuff (both below the hydraulic cylinders and in the well area);

5. Maintenance of the ventilation system;

6. Maintenance of the fire protection system;

7. Servicing the dosimetry system in the product chamber;

8. . Changing air filters, and

9. Leak testing the sources in the device.

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Device Ooeration:

46. Please provide a detailed drawing of the handle keys, including interaction with the control console, to verify that 10 CFR 36.23 interlock requirements have been

, addressed. .

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! 47. . Please describe the foreign object detection system referenced on page 18 of your -

application, including a drawing indicating the location of the detector, and its method of operation.

! 48. Page 14 of your application, the last sentence of the second to the last paragraph states that, "[d]uring transit, the sources do not irradiate the chamber until the topmost section of the door / source is engaged with the bottom of the upper inner column." This statement does not seem to be correct. Please clarify that the chamber is being partially irradiated as the sources move to the upper position.

49. 10 CFR 36.39(h) requires the irradiator to have a system for detecting fires in the product chamber. Drawing No. 304300 in your application shows a heat rise detector in the product chamber, but, since this detector is not discussed elsewhere in the application, it is not clear whether it is used for fire detection or for product quality control. Specify the detector to be used to detect fire in the product chamber, and describe its principles of operation. Please describe the components of the system, its principles of operation, the location of the components. Demonstrate that this detector is protected from mechanical and radiation damage. Describe the how the detector will activate the alarms and fire extinguishing system required by Part 36.

50. Provide the following additionalinformation concerning the emergency egress system.

1. Page 22 of your application states that there is a button in the chamber which will cut the electrical power to the hydraulics.10 CFR 36.23(b) requires that activation of the emergency egress system will cause the source / door to return to the down position. Confirm that depressing the emergency button in the product chamber will cause the door / source to be returned to the down position.

2. Page 22 of your application states that there is an inside release for each of the

! chamber doors which can be used any time the door / source is in the down position. In an emergency, it is likely that the door / source will have moved from the down position, blocking the chamber doors. Show that, if the door / source is not in the down position, using one of the inside releases will cause it to return to the down position. Note that this is also necessary to meet the requirements of 10 CFR 36.23(a).

3. 10 CFR 36.23(b) requires that activation of the emergency egress system will activate visible and audible alarms to alert at least one other individual. Describe that the alarms meet this requirement.

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51. 10 CFR 36.23(d) requires advanced activation of the audible and visible alarms warning that the sources are being moved. Describe how you implement this requirement in your irradiator.

52. As discussed in item 10.3 of NUREG-1556, Vol. 3, you must submit drawings and descriptions of non-safety critical components of the irradiator that could degrade the effectiveness or usefulness of safety critical components. Describe the features incorporated into your design, referencing appropriate drawings, to allow removal of hydraulic fluid (from a rupture or a leak), accumulated debris, and other foreign matter from the interior of the cuff. Address removal from both the outer area of the cuff and from the area directly below the door / source.

53. As discussed in Section 10.8 of NUREG-1556, Vol. 3, please note that "[t]he applicant should provide any special procedures that need to be followed when the product is installed at the user's facility." Accordingly, please submit the procedures that you will i provide to the user so that the user can safely operate and maintain the device. l

1. Submit procedures necessary for the maintenance of the device. These should include fully developed procedures for:

1. Installing the irradiator;

2. Performing initial surveys of the area outside the shielding of the irradiator;

3. Inspection and maintenance of the hydraulic system;

4. Inspection of wiring and servicing of the wiring;

5. Removal of debris from the interior of the cuff below the hydraulic cylinders

6. Removal of debris from the well area in the interior of the cuff directly below the door / source;

7. Testing the functioning of the product chamber doors and the emergency egress controls;

8. Testing the functioning of all audible and visible alarms;

9. Testing the source position indicator;

10. Maintenance of the ventilation system;

11. Maintenance of the fire protection system; and

12. Inspecting the air filtration system and changing the filters.

Note that, because these procedures will be included in the device registration from the NRC, they must not require use of GrayStar or any other service orovider specified by name. Any procedures that cannot be performed by the user should refer to "a service provider licensed by the NRC or an Agreement State." The procedures already included in your application dated April 15, 1999, should also be revised accordingly.

2. Submit procedures necessary to address adverse situations. These should include fully developed procedures for

1. Responding to a fire in the product chamber, L _

2. Returning the door / source to the fully down position should it stick in some other position; l

3. Responding to activation of an emergency egress control;

4. Responding to rupture of the seal on a hydraulic cylinder or other event that leads to hydraulic fluid getting into the interior of the cuff;

5. Responding to a power failure lasting more than a few seconds;

6. Verifying the integrity of the device after a natural disaster; and

7. Determining whether the device can be operated safely if the product chamber is damaged, for example by a fire or by penetration by a forklift.

As above, the procedures must not require the use of GrayStar or any other service provider specified by name. The actions to be taken in case of an extended power failure is discussed briefly in the narrative portion of the application, but should be formalized as a procedure.

3. Submit a copy of the Operator's Manual for the irradiator for us to be able to determine that "the distributor provides the user with the information necessary to safely operate and maintain the product" as specified in Section 10.8, NEREG-1556, Vol.3.

4. Submit other procedures necessary for the user of the irradiator, again omitting requirements for use of a service provider specified by name. Consider each of the items below and any other relevant topics. If the procedure should be standard for all users of the device, submit the fully developed procedure.

Otherwise, state that it should be reviewed as a part of the user's specific license application. The topics are:

1. Surveys to confirm the constancy of the dose rates around the irradiator;

2. Training of individuals who will operate the irradiator;

3. Reviews of the performance of each individual who operates the irradiator;

4. Ensuring product removed from the product chamber is free from contamination; and

5. Use of personnel dosimetry.

54. 10 CFR 36.23(a) requires the irradiator to incorporate a control that prevents the source / door from being moved from the down position if the product chamber doors are not fully shut. Describe more fully the interlock system for the product chamber doors.

Specifically, explain what prevents the hand!e key from being removed from the door if it is improperly latched (e.g., if the lower latching rod engages a hole that is not intended).

55. 10 CFR 36.31(d) requires that each control of the irradiator must be clearly marked as to its function. Submit a detailed diagram of the irradiator control panel showing the layout of the controls and all markings.

56. 10 CFR 36.31 requires the console of a panoramic irradiator to have a source position indicator. On page 16 of your application dated April 15,1999, you state that, since the door / source is in clear view through the outer product loading door, the operator can C

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instantly ascertain whether the source is up, down, or in transit. Given the dimensions of the door / source and the outer product loading doorway, it appears that the operator will not be able to readily ascertain at what point the source is in its transit, nor whether it has raised properly to its full up position. Furthermore, the operator may choose to close the outer security doors during irradiation, in which case the operator cannot see the door / source position. Describe the indicator located on the irradiator console that willindicate the position of the door / source. j

57. The list of quality assurance procedures in OlP-06-01 is incomplete. Specifically, OlP-12-01, " Control and Calibration of Measuring and Test Equipment," is not contained in the list of controlled documents. Review the list of controlled documents to ensure that no documents have been omitted. Submit a corrected version of OIP-06-01, or explain why OIP-12-01 is not included.

58. The section entitled "Use of Probabilistic Risk Assessment (PRA)" of Exhibit 7 of your application dated April 15,1999, indicates that there would not be any event which can lead to radiation exposure or loss of control of radioactive material. A number of I different failure modes are feasible. For example, events that could lead to the failure of l the source integrity could result in reduction of the shielding and dispersal of the l material through the ventilation system. Should the door / source fail to return to the down position, on-site removal of the sources could be necessary. The emergency egress control in the product chamber could fail to cut power to the hydraulics.

In order for the NRC to approve a device, we need to know that accidents such as these are very improbable or that, should the accident occur, the probable consequences are acceptable. Note that each of the accidents mentioned requires multiple events to occur in order for the accident to happen. PRA provides a framework for combining the probabilities of each event required to lead to an accident in order to evaluate the probability of the accident occurring. It also provides a framework for determining the probability of each of the possible outcomes should the accident occur.

Submit a modified Probabilistic Risk Assessment to demonstrate that the GrayStar Model 1 is safe. The PRA must include the probability of failure for each eleme " of the irradiator system (including failure of personnel to perform properly, failures cased by natural disasters, and internal disasters such as someone flooding the cuff interior) and the possible outcomes of each failure. It must then consider credible combinations of failure of two elements, whether those elements are related or independent, and so on for three, four, and more failures until all combinations with reasonable probability have been exhausted.

59. NRC requires that any person (as defined in 10 CFR 30.2) who service irradiator systems that directly or indirectly effect the safety of the device be licensed to perform such services pursuant to 10 CFR Part 30. Page 21 of your application states that, when necessary, GrayStar will perform wash-downs of the irradiator cuff and sample the discharge before releasing the water. Page 29 of the application states that any service or modification to the unit that might have an effect on radiation safety can only be performed or directly supervised by GrayStar, Inc. or its qualified representative. Page l 31, states that GrayStar will supervise installation and perform operational testing of l

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I' t-each unit prior to commercial operation. Pages 37 and 38 of the application state that GrayStar will perform leak testing of the irradiator sources and contamination surveys should a leaking source be suspected. The NRC requires a license to perform these services, which GrayStar does not currently have. To obtain information about applying for a license to perform these services, please contact our Region 1 office at (610) 337-5000. .

60. The drawings in Exhibit 9 of your application are labeled as preliminary drafts. Note that the device registration is based on the drawings and, once the registration is issued, any

~ changes in the irradiator design will require you to amend the registration certificate.

You will, therefore, need to submit the final versions of the drawings as soon as practical

so that they can be reviewed for the device registration.

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