ML20198H610
| ML20198H610 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 12/23/1998 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20198H607 | List: |
| References | |
| NUDOCS 9812290379 | |
| Download: ML20198H610 (4) | |
Text
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a UNITED STATES y
j NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 30666 4001
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SAFETY E'/ALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.140 TO FACILITY OPERATING LICENSE NO. NPF-12 SOUTH CAROLINA ELECTRIC & GAS COMPANY l
SOUTH CAROLINA PUBLIC SERVICE AUTHORITY VIRGIL C. SUMMER NUCLEAR STATION. UNIT NO.1 f
DOCKET NO. 50-395
1.0 INTRODUCTION
By letter dated May 21,1997, as supplemented on December 4,1998, South Carolina Electric
& Gas Company (SCE&G) requested NRC approval of changes to Virgil C. Summer Nuclear Statica (VCSNS) Technical Specification (TS) Section 54.7.6 " Control Room Normal and Emergency Air Handling System," and Section 3/4.9.11 " Spent Fuel Pool Ventilation System."
This TS amendment proposes changing the methods for testing the system charcoal adsorbers from American National Standards Institute (ANSI) N509-1980 to American Society for Testing i
and Materials (ASTM) D3803-1989.
2.0 EVALUATION Currently, TS Surveillance Requirements 4.7.6.c.2 and 4.7.6.d require the licensee to verify that control room (CR) laboratory carbon sample analysis results show a methyl lodide penetration ot < 1 percent when tested in accordance with ANSI N5091980 at a relative humidity (RH) of 70 percent and at 25'C. ANSI N509-1980 references ASTM D3803-1979. TS Surveillance Requirements 4.9.11.b.2 and 4.9.11.c specify that spent fuel pool (SFP) carbon sample laboratory analysis must meet ANSI N509-1980 testing criteria at a 30*C test media temperature.
This TS amendment proposes changing the methbds for testing the system charcoal adsorbers from ANSI N509-1980 to ASTM D3803-1989. SCE&G proposes to test the CR charcoal at 70 percent RH and 30*C, with a methyliodide penetration of < 2.5 percent. They also propose to
-l test the SFP charcoal at a 95 percent RH and 30"C, with a methyl lodide penetration of < 2.5 percent.
Essential elements for current testing requirements (ANSI NE09-1980), proposed testing requirements (ASTM D3803-1989), and their differences are I sted in Table 1 for the CR charcoal, and Table 2 for the SFP charcoal.
9812290379 981223 DR ADOCK 05000395 p
. Table 1. Control Room Charcoal Testing Essential Elements Current Testing Proposed Testing Differences Requirements Requirements 70% relative humidity 70% relative humidity none 25'C test medium 30*C test medium increase in test medium temperature temperature temperature from 25'C to 30*C
< 1% methyl iodide
< 2.5% methyl lodide increase allowed methyl penetration penetration iodide penetration frorn
< 1% to < 2.5%
no pre-equilibrating period 16-hour pre-equilibrating 16-hour increase in pre-period for new and used equilibrating period charcoal 16-hour equZbration period 2-hour equilibration period 14-hour decrease 11 for new charcoal for new and used charcoal equilibration period 120-minute methyliodide 60-minute methyl iodide 60-minute decrease in feed period feed period methyliodide feed period 240-minute elution period 60-minute elution period 180-minute decrease in elution period f
large test parameter small test parameter smaller test parameter tolerances tolerances tolerances RH testing requirements remain unchanged. Test medium temperature is increased from 25'C to 30*C for CR charcoal, but remains at 30 C for SFP charcoal. ASTM D3803-1989 challenges the representative charcoal samples at 30*C. The quantity of water the charcoal retains depends on temperature, with less water being retained as the temperature rises. The water retained in the charcoal decreases its efficiency in adsorbing other contaminants. Most charcoalis anticipated to be challenged at a temperature near 30*C, thus the
. Table 2. Spent Fuel Pool Charcoal Testing Essential Elements Current Testing Proposed Testing.
Differences Requirements Requirements 95% relative humidity 95% relative humidity none 30*C test medium 30*C test medium none temperature temperature
< 1% methyl iodide
< 2.5% methyliodide increase allowed methyl penetration penetration iodide penetration from j
< 1% to < 2.5%
i j
s no pre-equilibrating period 16-hour pre-equilibrating 16-hour increase in pre-period for new and used equilibrating period charcoal 16-hour equilibration period 2-hour equilibration period 14-hour decrease in for new charcoal for new and used charcoal equilibration period 120-minute methyliodide 60-minute methyliodide 60-minute decrease in feed period feed period methyllodide feed period i
240-minute elution period 60-minute elution period 180-minute decrease in elution period 4
\\
large test parameter small test parameter smaller test parameter tolerances tolerances tolerances
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ASTM D3803-1989 temperature test condition will yield realistic results.
The proposed TS require that laboratory testing of charcoal samples show's a methyliodide penetration of s 2.5 percent. The VCSNS control room ventilation and the fuel handling building exhaust plenum design basis calculations assume the charcoal has a 95% radiciodine removal efficiency. The proposed change to a s 2.5 percent penetration continues to support the VCSNS safety analysis assumption of s 5 percent penetration. The s 2.5 percent methyl
, lodide penetration labo atory testing acceptance criterion includes a safety factor of 2 which provides the staff with a degree of assurance that, at the end of the operating cycle, the charcoal will be capable of performing at a level at least as good as that assumed in the licensee's dose analysis.
ASTM D3803-1989 provides results which are more easily reproducible compared to ASTM D3803-1979. This is due to smaller tolerances on various test parameters, and the requirement for pre-equilibrating the charcoal sample. During the pro-equilibrating, the charcoal is exposed to an air flow controlled at the test temperature and RH before feeding the challenge gas through the charcoal. The purpose of the pre-equilibrating test phase is to ensure that the charcoal has stabilized at the specified test temperature and RH. This results in the charcoal adsorbing all the available moisture before challenging the charcoal with methyl iodide. Having every charcoal sample begin the test at the same initial conditions ensures reproducibility of the results. Hence, the proposed testing in accordance with ASTM D3803-1989 results in a more realistic prediction of charcoal capability. As discussed above, the more realistic testing provides results that are more easily reproducible and includes a safety factor of 2. Accordingly, the staff concludes that the proposed TS changes are acceptable.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the State of South Carolina 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 NRC 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 pub';c comment on such finding (62 FR 33133). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 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 CONCLUSIOE The Commission has concluded, based on the considerations discussed above, that (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, 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 Contributor: M. Padovan Date: December 23, 1998 l
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