ML21246A270

Email from P. Pater, Ga, to M. Doell, NRC - Ga Triga Fssr Clarification Items

ML21246A270
Person / Time
Site:	General Atomics
Issue date:	05/18/2021
From:	Pater P General Atomics
To:	Marlayna Vaaler Doell Reactor Decommissioning Branch
Marlayna Doell, 301-415-3178
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Download: ML21246A270 (8)

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From: Pater, Paul To: Doell, Marlayna

Subject:

[External_Sender] RE: RE: RE: RE: RE: GA TRIGA FSSR Clarification Items Date: Tuesday, May 18, 2021 12:02:05 PM Attachments: Scenario 3 Worker External Exposure.pdf TRIGA Pipe Filled Cyl Surface.pdf

Hi Again, First, my apologies for not appropriately addressing your question yesterday. After I received your email requesting a conference call, I realized that maybe there is something I didnt see.

Well, this morning I found an error with the MicroShield numbers I provided and assumed that is the concern.

While setting up the pipe geometry in MicroShield for Scenario #3, I ran several different cases, to ensure I properly modeled the pipe geometry. The bottom line is that while I provided the correct MicroShield report with the proper geometry, I didnt provide the correct Effective Dose Equivalent value which came from a different pipe geometry case. I have included both case reports and both Dose Equivalent reports for your review. The correct Effective Dose Equivalent value for Scenario #3 is 2.687E-3 mrem/hr. Regarding the bounding values in Section 7.4.3 of the FSSR, the doses for the upper and lower limits are 2.79 mrem/yr and 0.107 mrem/yr respectively.

I hope this helps clear up the confusion and allows for a more productive meeting next week.

Please let me know if you need anything else.

Thanks so much,

Regards, Paul

From: Doell, Marlayna <marlayna.doell@nrc.gov>

Sent: Tuesday, May 18, 2021 9:20 AM To: Pater, Paul <paul.pater@ga.com>

Subject:

-EXT-RE: RE: RE: RE: RE: GA TRIGA FSSR Clarification Items

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Perfect! I will set us up over Teams and just have to imagine your smiling faces. Look for a scheduler shortly!

And yes, I am available for the next 45 minutes (until 10 AM your time, and then after noon your time for the rest of the day, so give a shout whenever!

Cheers, MVD

From: Pater, Paul <paul.pater@ga.com>

Sent: Tuesday, May 18, 2021 10:04 AM To: Doell, Marlayna <marlayna.doell@nrc.gov>

Subject:

[External_Sender] RE: RE: RE: RE: GA TRIGA FSSR Clarification Items

Hi Marlayna, GA uses Teams for their virtual meetings and screen sharing, however, for security reasons we do not have cameras on our computers.

Bob Liz and I would like to meet on Tuesday, May 25th at 11-12 PM EST. This way if something comes up we still have the other dates to work with.

By the way are you available for a phone call?

Thanks, Paul

From: Doell, Marlayna < marlayna.doell@nrc.gov>

Sent: Monday, May 17, 2021 2:03 PM To: Pater, Paul < paul.pater@ga.com>

Subject:

-EXT-RE: RE: RE: RE: GA TRIGA FSSR Clarification Items

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Thanks Paul!

This was very helpful and I have passed everything along to the technical team. We chatted briefly and I think a call would still be beneficial just so all you HP folks can get together and make sure we are speaking the same language Below are some dates/times that our folks are free next weeklet me know if any of these match up on your end and I will send out a scheduler as needed. Also, does GA use Teams or WebEx? I thought this might be easier than just a teleconference in case we want to share screens or any of that good stuff. Let me know and I can set up either if possible!

Potential GA/NRC Meeting Dates:

Tuesday, May 25 12 PM EDT Wednesday May 26 4 PM EDT Thursday May 27 - any time between 10 AM and 4 PM EDT

Have a great rest of your afternoon and I will talk to you soon!

Marlayna

From: Pater, Paul < paul.pater@ga.com>

Sent: Monday, May 17, 2021 12:47 PM To: Doell, Marlayna < marlayna.doell@nrc.gov>

Subject:

[External_Sender] RE: RE: RE: GA TRIGA FSSR Clarification Items

Hi Marlayna, Yes, the crazy week ended well and weekend was very relaxing. Believe it or not we had what I call miserable weather like Seattle, cold and drizzly, so mostly indoors projects around the house. After reading the email below I was thrilled to know that our efforts to submit a thorough, concise FSSR with organized supporting documentation was well received. It was our intention to tell the TRIGA story and make it convenient for the reader to apply release criteria to the survey results. Im happy to know the review team appreciated GAs effort in submitting a quality FSSR.

As far as the clarification question below, please see the last paragraph in section 7.3.4 of the FSSR. More than likely I was not clear enough regarding my intention to provide results in effective dose equivalence instead of mR/hr. Both GA and your review team got the same MicroShield result in units of exposure rate at 2.94E-3 mR/hr. However, I felt that since the release criteria is dose based and our results in RESRAD are in mrem, I needed to provide a dose value for Scenario #3. MicroShield has an option to generate a case Dose Equivalent Report, which I printed. In this report, ICRP 51 and 74 values are provided for critical organs along with Effective Dose Equivalent Rate. I choose ICRP 51 simply because it was more conservative. From this point, I can estimate hours worked on the pipe and provide total dose to the representative person.

If your review team would like to discuss this approach and/or any other information we provided, we will make ourselves available to discuss via conference call at your convenience.

As always, we appreciate the efforts of your staff and open communication during this project.

Sincere regards, Paul

From: Doell, Marlayna < marlayna.doell@nrc.gov>

Sent: Monday, May 17, 2021 8:35 AM To: Pater, Paul < paul.pater@ga.com>

Subject:

-EXT-RE: RE: RE: GA TRIGA FSSR Clarification Items

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Hi again!

I hope that your crazy week ended well and that you and the whole team had a great weekend I am happy to report that there will be NO formal NRC RAIs for the General Atomics FSSR / license termination review. This is basically unprecedented in the history of FSSR reviews, so you and your folks are to be highly commended. The NRC sadly doesnt give out medals (that I am aware of any way!), so I hope my heartfelt appreciation for such a good quality product will be enough!

There was one additional clarification question identified which is captured below, so after your folks have a chance to take a look and prepare whatever discussion/documentation they would like to provide we can set up a call to discuss, and assuming that goes well move on to preparation of the final license termination documentation. There is no particular rush on this, and next week would probably be better for a phone call on our end as our annual decommissioning counterparts meeting takes places all this week, so let me know what works best for you and we can figure it out from there!

GA FSSR Clarification Question

The NRC staff were not able to reproduce the results of the effective dose equivalent rate in the MicroShield calculations from Section 7.3.4 of the FSSR (reported as 4.05E-3 mrem/hr). We did, however, get the same result as in the submittal for the exposure rate (2.94E-3 mR/hr). We used Versions 11 and 12 of MicroShield for our calculations, while GA used Version 8, but would not expect the different versions to cause a major difference in the calculated results (our results for the dose rate were ~50% less than GAs).

Would it be possible to obtain a copy or otherwise discuss the Dose Equivalent Report from the GA calculations? Also, if the GA team any thoughts on what might be causing the difference between their results and ours could they let us know?

Cheers, Marlayna 301.415.3178 605.348.2334 (home)

From: Pater, Paul < paul.pater@ga.com>

Sent: Thursday, May 13, 2021 11:07 AM To: Doell, Marlayna < marlayna.doell@nrc.gov>

Subject:

[External_Sender] RE: RE: GA TRIGA FSSR Clarification Items

Hi Marlayna, No worries! It has worked out for the better. This week has been challenging with numerous laboratory requests accompanied by limited staff.

We are ready to provide any information you need or discuss what has already been provided.

Best, Paul From: Doell, Marlayna < marlayna.doell@nrc.gov>

Sent: Wednesday, May 12, 2021 3:01 PM To: Pater, Paul < paul.pater@ga.com>

Subject:

-EXT-RE: RE: GA TRIGA FSSR Clarification Items

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Hi Paul!

I realized I never responded to you on the below and wanted to let you know you are not forgotten!

The technical folks super appreciate the info you guys provided and are in the process of reviewing it so that I can set up a call as needed. Unfortunately the workload exploded a little this last couple of weeks so some things are getting shuffled in the schedule, but we should be back on track with GA next week (and have the other things out of the way!) so I will look to get the final update to you on any additional clarifications/RAIs ASAP and we can go from there.

Please give me a shout if you need anything additional in the meantime and have a great afternoon!

Marlayna 301.415.3178 605.348.2334 (home)

From: Pater, Paul < paul.pater@ga.com>

Sent: Wednesday, May 5, 2021 12:45 PM To: Doell, Marlayna < marlayna.doell@nrc.gov>

Subject:

[External_Sender] RE: GA TRIGA FSSR Clarification Items

Hi Marlayna, Welcome back! I hope your mini vacation was relaxing and a nice break from the homestead.

Initially, my goal was to provide the documentation you requested with a short email before your return but we just didnt get there. As of yesterday, we have put together documents and supportive information to assist with reviewing the scaling factors question and with the phone discussion next week. I have attached several documents for your review along with the following explanations to provide some clarity. Keep in mind we have only attached the results pages but can provide the entire reports if you desire.

Let me start by confirming that we had a typo in the table we provided in our email sent on February 19, 2021. For soil sample #1 the Cs-137 concentration in pCi/g should have read 0.026 instead of 0.266. This is important because it was used in the Sample Ratio Average calculation to obtain the scaling factor of 1.17. This value is mentioned in your email below. If you remove sample numbers #1 and #8 (<LLD), the new Sample Ratio Average scaling factor is 1.848. Using this ratio value, the Sr-90 concentration increases to 170.7 pCi/g. The RESRAD case for the pipe at the surface was rerun with the new Sr-90 concentration with the total dose increasing slightly from 6.647 mrem/yr to 6.672 mrem/yr. Please see the attached table (TRIGA Sr-90 Cs-137 Ratio), TestAmerica results, and page 8 of the RESRAD report.

Regarding the pipe scale samples. Attached is a single page from TestAmerica showing both results. The GA-5-SCALE-PIPE-01 sample is pipe scale from the inside of the broken section of pipe. This sample was taken back in August 2019. GA performed a gamma spec analysis on August 19, 2019 but the sample was not sent to TestAmerica until the end of October. Again, we were still in the discovery phase. The GA-5-SOIL-PIPE-01 sample was primarily outside pipe scale mixed with some soil. GA performed a gamma spec analysis on October 25, 2019 and sent the sample to TestAmerica in late October along with the other samples. The pipe scale Sr-90/Cs-137 ratio can also be found on the attached table (TRIGA Sr-90 Cs-137 Ratio). The gamma spec reports are also included.

Regarding the RESRAD Pathways and Assumptions in your email, I did neglect to turn off the pathways which do not apply to GA. It was not our intention to include all pathways but radon, however, it is the more conservative approach.If the NRC is willing to acknowledge and accept that two different pathway analyses were provided, GA will also acknowledge and accept the differences. We feel this is a reasonable approach considering the values are at the micro mrem/yr level.

We are ready to discuss these results and conclusions via conference call at your convenience.

Best Regards, Paul

From: Doell, Marlayna < marlayna.doell@nrc.gov>

Sent: Monday, April 26, 2021 4:06 PM To: Pater, Paul < paul.pater@ga.com>

Subject:

-EXT-GA TRIGA FSSR Clarification Items

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Hi Paul!

I hope that you and the whole TRIGA gang are doing well this week (it is STILL snowing here so I am mad at all of you and my family in San Diego as well at the moment ). We are churning away merrily on our review of the GA FSSR / license termination request, and are pretty close to declaring that we have NO additional information requests (RAIs) associated with this action, which would be awesome all around for all sorts of reasons. I am waiting for one more dose assessment reviewer to confirm that condition next week, and we can proceed accordingly from there!

In the meantime, there are a couple of clarification items that have come up, and do not reach the level of full/formal RAIs, but would still be nice to discuss or otherwise have (I think easy!) answers to. I have included these minor topics below, and figured I would leave it up to your folks to decide whether a call or an email back would be the easiest next step. So in no particular order, the clarifications are:

GA Buried Pipe Dose document: Sr-90/Cs-137 Scaling Factor After reviewing GAs response to the NRCs initial request for information on the range of ratios observed for Cs-137 and Sr-90 in site samples and any analyses done to develop and justify the assumed scaling factor, it was stated that two pipe scale samples were sent to TestAmerica during buried pipe cleanout. Could we get a copy of those two scale sample analyses?

Based on the 11 soil sample results taken after a portion of the floor was removed in the TRIGA Mark F reactor room for the site-specific Sr-90/Cs-137 scaling factors, which of the data were > LLD?

What are the dose consequences if the amount of Sr-90 is more than assumed by the scaling factor? Has GA considered an analysis using a more reasonably conservative scaling factor based on the TestAmerica data, rather than the April 2019 memo or true average of the data?

Note that this might already be covered by the RESRAD cases already run with scaling factors between.81 (memo) and 1.17 (average of 11 data points).

Section 7.3.1 RESRAD Pathways and Assumptions This section of the FSSR states that RESRAD pathways for Scenarios 1 and 2 will be External Gamma, Inhalation, and Soil Ingestion. However, Scenario 1 (buried pipe at depth) considers all pathways except radon. This appears to have led to the RESRAD output value for Scenario 1 (1.854e-6 mrem/yr) being two orders of magnitude too high. This is likely an acceptable approach since it is more conservative, but is that was GA intended?

These have not been polished up or otherwise reviewed by anyone but me and the technical folks, but hopefully they make sense on your end and we can figure out how best to painlessly address them. I personally think a call to chat through most of these, followed by an email to follow-up on the couple of info requests would likely be more than sufficient, but I am happy to do whatever makes your side more comfortable (including asking for this information via a more formal process if that is GA managements preference!).

I am going to be out of the office from April 28-May 4 (and actually out of towngasp!), but can set something up for when I return and/or wait until I have heard back from the final reviewer so we can discuss anything additional that might come up in one go. Please let me know what your team prefers, and give me a shout if you have questions or need anything additional in the meantime as I will be checking in periodically throughout the week. Thanks as always for the support and enjoy your actual spring weather out in Southern California!

Cheers, Marlayna

Marlayna Vaaler Doell

~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Decommissioning Project Manager U.S. Nuclear Regulatory Commission NMSS/DUWP//RDB

Phone: 301.415.3178 Mobile: 440.668.7399 Home: 605.348.2334 E-mail: marlayna.doell@nrc.gov Office Location: Fulltime Telework from Rapid City, South Dakota!

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