ML20244B622
| ML20244B622 | |
| Person / Time | |
|---|---|
| Site: | Hope Creek  |
| Issue date: | 09/24/1981 |
| From: | Gammill U Office of Nuclear Reactor Regulation |
| To: | Leckie F NCS CORP. (FORMERLY NUCLEAR CONTAINMENT SYSTEMS |
| Shared Package | |
| ML20236Y423 | List: |
| References | |
| NUDOCS 8111090008 | |
| Download: ML20244B622 (4) | |
Text
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TMI Site r/f TM1 P0 HQ r/f A A F, 1
September 24, 1981 mua noms,
OCT 061981 Mr. Fred Leckte, Nuclear containment systems, Inc.
1225 Dublin Road Columbus, Ohio 43215
Dear Mr. Leckie:
The subject of what conditions are applicable for laboratory methyl iodide tests is certainly not straightforward, as you indicated in your letter of July 1 (attached).
Your letter has been referred to my office for resoluticn.
Uith AflSI and ASTM standards, regulatory guides, and technical specifications, it can be a confusing area.
First, plant technical. specifications are.the over-riding controlling document; If these technical specifications list specific conditions, perform the test under these conditions.
If some conditions, but not all are specifled, then the ASTH procedures in ASTM 03803-1979 " Standard Test Methods for.Radiofodine Testing of Huclear-Grade Gas Phase Msorbents",
should be invoked for the remainder of the 1:enditions.
If cha.11enged, a technical case can easily be made for using the ASTH procedures.
Now, if the technical sp'ecific'ations refer to Regulatory Guide 1.52, Revision 2, March 1978, then page 6 of this document' points you' in the right direction.
In Section C.G.b.(3), the reader is directed:
" Repre-sentative samples of used activated carbon pass the laboratory tests given in Table 2." Table 2 (on page 7 of Regulatory Guide 1.52) refers to Table 5-1 of ANSI-H509-1975 for the test conditions (see the third column in Table 2), and also specifies the allowable penetration.
As an example, for two inch systems outside containment with heaters, used carbon should be tested per test 5.b of NISI-N509-1976, to a penetration of less than 1%, except 70% relative humidity is applicable, not 955.
Now there are two minor variatio6s.
ANSI-N509-1980 has now been published, and does not numbar the tests.
The apa11 cable test (i.e., Test 5.b) is labeled as Hethyl Iod.ine, 30"C. 95ll; R.H.
Again, note that Regulatory Guide _1:52 says. to perform the test et70 relative humidity with s enetration.of'.11 (and this takes precedence over. the 951 relative p'umidtty ~and'3". penetration in Att$1-N509-1980). Also,TT509-1976 refers h
to the RDT M16-1T for detailed procedures, whereas N509-1980 refers to ASTM D3803.
The issuance of H509-1980 (an be inte, preted as allowing the utility an option.
They can either literally invoke their technical specifications and use N509-1975. Or, since H509-1980 has been issued and is an ate they should be able to use N509-1980, with its temperature l
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9 Mr. Fred Leckte t
September 24, 1981 of 30*C instead of 80*C.
Technically, the best way to go is to use N509-1980, since it is an updat's and refers to the latest industry approved test procedures (ASTM 03803). No field inspector shou',d object.
since the utility is increasing its safety margin by using the latest industry accepted guidance.
Therefore, I will answer your specific question on testing when the specification refers only to Regulatory Guide 1.52: use the latest industry accepted guidance and test at 30*C, 701 relative humidity to a methyl fodide penetration of 1% with A.'iSI-N509-1980 and AST11 D3803 as the basis.
(This, I repeat, is an update of the technical specification, which indicates to use 4509-1976).
The second complication is a system with no air heaters.
It does not follow to test at 705 relative humidity, and no column in Table 2 of Regulatory Guide 1.52 applics.
Testing should be perfor;::ed according to
~ Test 5.b of ANSI-i!509-197G which is updated (again) by the' test labeled Methyl lodine 30*C, 95% relative humidity in ANSI-tiSO9-1930 (with ASTM 03803 for detailed procedures).
Acceptance criteria should be based on the accident analyses performed: If 90% credit was assumed in the accident analysis, the allowable penetration is 51; if 70% credit was assumed in the accident analysis, the allowable penetration is 10%.
Therefore, again to answer your specific question:
For systems with no heaters test the.used carbon at 30*C, 95% relative humidity and ASIM D3803 procedures, to a penetration based on that assumed in the accidertt analys's.
I hope this clears up your technical concerrs.
If you haYe further questions, pl_ ease feel free to contact me at 301-492-8361.
Sincerely, William Gamill, Chief Effluent Treatment Systems Branch Office of Nuclear Reactor Regulation Attach nent: As Stated bec: W. Kreger R. Bangart L. Higgenbotham C. Willis R. Houston
- 5. Snyder L. Barrett R. Bellair-M. Welastela
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ATTACHMENT 4 PHOTOCOPY OF PAGE 63 FROM
" NUCLEAR AIR CLEANING HANDBOOK" (ERDA 76-21) 1 l
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63 tion will depend on the deg'ee of fuel burnup) will camber of screens used to hold the adsorbent in saist in the forms of best-gamerating radionodine and modular call and pSU adsorbers. Gas residence time will contribues to fisusoe product decay bestang of the can be increased by increasing bed depth or, for a carbon, which, if adequate cookas airflow is not fixed bed depth, by decreasing airflow velocity (i.e.,
maintained, saay esses t yh of trapped iodine by underrating). Incrossas bed depth over the 2 in.
oc ignition of carton in the beds. Of these two mimmum employed in both PSU and modular cell possibilities, desorption of iodine is the more serious adsorber designs and W in Regulatory for two reasons; first because it would constitute a Guide 1.32" has the advantap of increasing system loss of containment for radiciodine, and secondly reliability by increasing holding capacity. It has the because bed temperatures will never reach the igni-disadvantages of higher cost and,in activated carbon j
tion point if sufficient airflow to prevent desorption systems, of slightly decreasing ignition temperature."
of trapped iodine is maintained. Sufficient airflow is ignition temperature also decreases with aging of the necessary to keep bed temperatures below 230*F, carbon, particularly in continuously on-line systems.
probably on the order of 6 to 10 fpm. An M PL of 2.5 Minimum operational airflow capacity can be deter-mg total iodine (including inert and radioactive mined from the equation isotopes as both elemental iodine and organic com-pounds) per gram of carbon is considered adequate to C= gg q (3.2) 28.8 E prevent significant fission product decay heating provided a minimum airflow of 6 to 10 fpm under where accident conditions is maintained."
C= minimum system design airflow, cfm; To determine the minimum quantity of carbon N= number of cells or adsorber assemblies in the required in a specific system,the quantity ofinert and bank (N = 1 for a PSU);
radioactive iodine that may be trapped in the n = number of beds per adsorber assembly (n = 2 adsorbers must be estimated. Using the MPL of 2.5 for IES CS-8 type 11 cells);
mg total I/mg C and the assumptions on iodine i = bed thickness, in.(r = 2 for IES CS-8 type 11
_ distribution noted previously, the minimum quantity cells);
of carbon in the system can be estimated from the A = total area of all bed screens of one cell or of a eq9 anon PSU, in/;
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i tal unPeyorated area of screens having t5tal C= 0.22 Q,
(3.1) area A, m.,,
S= number of screens per cell or PSU adsorber; where T= minimum gas residence time required for C= minimum quantity of carbon required, Ib; effective sorption, sec.
Q= potential iodine inventory that could be re-For IES CS-8 type 11 cells and gas residence time of leased, s.
0.25 sec, Eq. (3.2) reduces to a
Using this equation, a 1000-MW(e) reactor with a CH = 333 N --
(3.3) potential iodine inventory of 15,000 g would require For an installation of mod ular cell adsorbers, gas res-a mmimum of 3300lb of carbon to provide adequate idence time can also be increased by providing two protection against desorption and igmtion under banks in series. This not only increases holding ca-accident conditions. This amount is more than pacity and system reliability but avoids the de-adequate to meet the requirements for efficiency and, crease in carbon ignition temperature (since each bed retention under normal conditions, is only 2 in, thick) and provides series redun.
System airflow is a function of the quantity of dancy. Because the first bank serves as a guard bed, carbon in the system and of gas residence' time.
most of the aging, weathering,and poisoning of the Although the rainimum gas residence tiene of 0.20 sec adaorbent would take place in the first bank, and is required for eNective sorption of organic wrvice life of the second bank should be greatly radioiodine ccg ', a miaimum of g.25 see is extended. All these advantages are gained at in-recommended for design purposes. This provides the creased investment costs, building space charge conservatissa necessary to account for adsorbent bed (because e(the greater space required), and operation 5
thinning due to the nearly unavoidable warpage and costs (because of the greater power requirements L_____________________
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