ML20132F817
| ML20132F817 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 12/23/1996 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20132F815 | List: |
| References | |
| NUDOCS 9612260103 | |
| Download: ML20132F817 (5) | |
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UNfTED STATES I}
NUCLEAR REGULATORY COMMIS810N g
WASHINGTON. D.C. 300BMeet
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1 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION
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RELATED TO AMENDMENT NO.110 TO FACILITY OPERATING LICENSE NO. NPF-43 i
DETROIT EDISON COMPANY i
FERMI-2 DOCKET NO, 50-341
1.0 INTRODUCTION
By letter dated March, 25, 1996, the Detroit Edison Company proposed a revision to the Fermi 2 Tr hnical Specifications (TS) 3/4.6.5.3 " Standby Gas Treatment System (SGTS)" and 3/4.7.2 " Control Room Emergency Filtration System
'(CREFS)." Specifically, the licensee proposed to change the SGTS Surveillance Requirements (SRs) 4.6.5.3.b.2 and 4.6.5.3.c and the CREFS SRs 4.7.2.1.c.2 and 4.7.2.1.d.
In each case, the proposed TS change specifies that the laboratory test of charcoal should use the American Society for Testing and Materials (ASTM) D 3803-1989 test protocol instead of the RDT M 16-IT test protocol referenced in American National Standards Institute (ANSI) N509-1976.
In addition, the licensee also proposed to specify the test conditions for temperature and relative humidity (RH) as well as the allowable methyl iodide penetration for the laboratory tests.
2.0 EVALUATION
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The proposed TS amendment changes the testing requirements used to determine the operability of the charcoal in the SGTS and CREF5. The charcoal is l
provided to remove iodine from the air as it passes through the SGTS and CREFS. There are no changes to the physical design or operation of the i
facility. Table 6.2-11 of the Updated Final Safety Analysis Report (UFSAR) should be revised to reflect that the SGTS charcoal will be lab tested to
-ensure a 99.9% removal efficiency for methyl iodide.
The TS Bases are not affected.
The Femi 2 SGTS SRs 4.6.5.3.b.2 and 4.6.5.3.c presently specify Regulatory Position C.6.a of Regulatory Guide (RG) 1.52, Revision 2, " Design, Testing, and Maintenance Criteria for Post Accident Engineered-Safety-Feature Atmosphere Cleanup System Air Filtration and Adsorption Units of Light-Water-Cooled Nuclear Power Plants," as the requirement for the laboratory testing of the charcoal. RG 1.52 references ANSI N509-1976, " Nuclear Power Plant Air Cleaning Units and Components." ANSI N509-1976 specifies that testing is to be performed in accordance with paragraph 4.5.3 of Military Specification RDT M 16-IT, " Gas Phase Adsorbents for Trapping Radioactive Iodine and Iodine Components" (year not specified) at 80 *C and with a 25 *C pre-and post-test sweep. The essential elements of this test are:
70% RH for air filtration systems designed to control the RH to 70% (i.e., filtration systems with heaters) 9612260103 961223 PDR ADOCK 05000341 P
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l A 5-hour pre-test charcte tvaple equilibration at 25 *C and 70%
i RH i
A 2-hour injection of cri...enge gas at a test medium temperature e
of 80 *C and 70% RH j
A 2-hour post-test sweep at.25 *C and 70% RH Methyl iodide penetration of less than 0.175%
l 4
i The licensee proposed to change Fermi 2 SGTS SRs 4.6.5.3.b.2 and 4.6.5.3.c to i
reference ASTM D 3803-1989, " Standard Test Method for Nuclear-Grade Activated i
Carbon" as the requirement for the laboratory testing of the charcoal.
l ASTM D 3803-1989 is updated guidance based on ASTM D 3803-1979 which is i
updated guidance based on RDT M 16-IT. The essential elements of the proposed TS change for testing per ASTM D 3803-1989 are:
70% RH A 2-hour pre-test thermal stabilization at 30 *C A 16-hour pre-test charcoal sample equilibration at 30 *C and 70%
i M
A 2-hour equilibration of the sample at 30 *C and 70% RH A 1-hour injection of challenge gas at a test medium temperature i
of 30 *C and 70% RH A 1-hour post-test sweep at 30 *C and 70% RH Methyl iodide penetration less than 0.1%
+
i The major differences between the current TS and the proposed TS change requirements for carbon testing are:
Technical Specifications Current Proposed Test Temperature 25 *C, 80 *C, 25 *C 30 *C 4
l Total Pre-Test Equilibration 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> 18 hours Methyl Iodide Penetration 0.175%
0.1%
i i
In addition, the current TS allow larger tolerances of laboratory test -
protocol parameters than the proposed TS.
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These differences will be addressed individually and will be shown to be acceptable.
As stated above, the licensee proposed to challenge the representative carbon samples at 30 *C rather than 80 *C.
Information Notice 86-76, " Problems Noted in Control Room Emergency Ventilation Systems," indicated that laboratory testing of charcoal at a temperature higher than that expected during the course of an accident could result in an overprediction of the capability of the charcoal to remove methyl iodide. The quantity of water retained by i
charcoal (carbon) is dependent on temperature. Generally, the higher the temperature the less water retained. The water retained by the carbon j
decreases the efficiency of the carbon to adsorb other contaminants. At 30 *C
(
.and 95% RH, carbon will retain about 40 weight percent water. At 80 *C and j.
95% RH, carbon retains only about 2 to 3 weight percent water. Therefore, the lower temperature test of the proposed TS'will yield more conservative results than the present TS.
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, ASTM D 3803-1989 specifies a test temperature of 30 *C for both the pre-and post-test sweep instead of the 25 *C required by ANSI N509-1976. There is 4
little difference in the adsorption behavior of carbon between these two i
temperatures. The 25 *C parameter is more conservative. The increase from 25 *C to 30 *C does not represent a significant decrease in the test results.
However, the 30 *C test temperature is more representative of the conditions that the charcoal will be exposed to under all potential events, and is, therefore, acceptable.
Pre-test N midity equilibration is achieved by sweeping air of the appropriate humidity through the test carbon. The present TS reference to ANSI N509-1976 (RDT M 16-lT) requires the charcoal to be equilibrated to 25 *C and 70% RH.
The methyl iodide test medium would then be instantaneously introduced at i
80 *C.
Testing the charcoal with such thermal step changes is technically incorrect because it results in condensation forming on the charcoal sample.
Condensation on the charcoal sample itself (" wetting the bed") results in the test being invalid. This is supported by paragraph 12.41. of ASTM D 3803-1979 l
hich states with respect to relative humidity of the test medium that, " tests at saturation or above give very erratic results." Because of this, the j
ASTM D 3803-1989 standard includes a 2-hour pre-test thermal-only stabilization at 30 *C and specifies a temperature of 30 *C for all phases of 4
the test. Therefore, ASTM D 3803-1989 is a better test because it solves the problem of the formation of condensation on the charcoal sample.
The ASTM D 3803-1989 standard is more stringent than the RDT M 16-1T standard since it has smaller tolerances for various parameters of the test protocol that result in more acceptable reproducibility of the test and it requires that the carbon sample be pre-test equilibrated for a much longer duration.
i The longer pre-equilibration is conservative since it will completely saturate the representative carbon sample to the condition to which the subject charcoal adsorbers are expected to be exposed during design-basis conditions.
During the pre-equilibration, the charcoal is exposed to a flow of air controlled at the test temperature and RH before the challenge gas is fed through the charcoal. The purpose of the pre-equilibration phase of the test is to ensure that the charcoal has stabilized at the specified test temperature and RH for a period of time which results in the charcoal adsorbing all the available moisture before the charcoal is challenged with methyl iodide. Therefore, the measured methyl iodide removal efficiency is lower than it is if pre-equilibration is not performed.
In addition, the current testing at 80 *C thermally regenerates the charcoal causing the test to provide results which over-predict the capability of the charcoal. Hence, the proposed testing in accordance with ASTM D 3803-1989 standard would result in a more realistic prediction of the capability of the charcoal.
The licensee proposed a methyl iodide penetration of 0.1% for the 6-inch bed of charcoal in the SGTS. Table 2 of RG 1.52 specifies a penetration of 0.175%
for beds with a depth of 4 inches or greater. The proposed penetration of 0.1% is acceptable because it is more conservative than the guidance provided in RG 1.52.
i The proposed changes to CREFS SRs 4.7.2.1.c.2 and 4.7.2.1.d were similar to the changes proposed for SGTS SRs 4.6.5.3.b.2 and 4.6.5.3.c except a methyl iodide penetration of less than 1.0% was proposed for the 2-inch bed of charcoal for the emergency makeup filter train and the 4-inch bed of charcoal for the emergency recirculation air filter train.
The proposed 1.0% methyl iodide penetration is based on the charcoal filter efficiency of 95% credited
. in the dose analysis for both the 2-inch and 4-inch beds.
If, in the future, higher credit is required for the 4-inch bed of charcoal, then prior NRC 4
approval must be obtained for a TS amendment request to test to a more restrictive methyl iodide penetration. Since the proposed methyl iodide penetration limit is the same as the present penetration limit, the staff finds the proposed changes to CREFS SRs 4.7.2.1.c.2 and 4.7.2.1.d acceptable.
The requested changes revise the charcoal filter laboratory testing in SRs 4.6.5.3.b.2, 4.6.5.3.c, 4.7.2.1.c.2, and 4.7.2.1.d, such that existing test methodology in the TS is revised to reflect current NRC guidance on laboratory testing of charcoal. The staff has evaluated this change and concludes that the testing methodology proposed by the licensee adequately demonstrates the operability of the charcoal in the SGTS and CREFS and is therefore acceptable.
The requested changes to TS 3/4.6.5.3 " Standby Gas Treatment System" and TS 3/4.7.2 " Control Room Emergency Filtration System" revise the SRs for the charcoal filter laboratory testing. The staff has determined that using the proposed ASTM D 3803-1989 testing standard at 30 "C, 70% RH, and a methyl iodide penetration of 0.1% for the SGTS and 1.0% for the CREFS will result in a more realistic prediction of the capability of the charcoal. Therefore, the staff concludes that the testing methodology proposed by the licensee adequately demonstrates the operability of the SGTS and the CREFS and is accepteble.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Michigan state official was notified of the proposed issuance of the amendment. The state official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
The amendment changes surveillance requirements. The staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration and there has been no public comment on such finding (61 FR 40014). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFP, 51.22(c)(9).
Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
5.0 CONCLUSION
The staff has concluded, based on the considerations discussed above, that:
4 (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, l
and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributors: John Segala Andrew Kugler Date:
December 23, 1996
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i DATED: December 23. 1996 i
l AMENDMENT NO. 110 TO FACILITY OPERATING LICENSE NO. NPF-43-FERMI-2 (Docket' FlTE i
PUBLIC' PD3-1 R/F.
J. Hannon t
J. Roe C. Jamerson A. Kugler OGC G. Hill, IRM (2)
C. Grimes, 0-IlF23 J. Segala ACR$
i M.~ Jordan, RIII i
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