ML20073S431
| ML20073S431 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 05/25/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20073S428 | List: |
| References | |
| NUDOCS 9406030122 | |
| Download: ML20073S431 (3) | |
Text
_ _ _ _ _ _ _ _ - _ - - _ _ _ _ _ ___ _
je nau Jg 4
E UNITED STATES 5'
ti NUCLEAR REGULATORY COMMISSION k.....,/
WASHINGTON "LC. 20555-Occ1 SAFEYY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.11a TO FACILITY OPERATING LICENSE NPF-35 AND AMENDMENT NO. 112 TO FACILITY OPERATING LICENSE NPF-52 DUKE POWER COMPANY. ET AL, CATAWBA NUCLEAR STATION. UNITS 1 AND 2 DOCKET NOS. 50-413 AND 50-414
1.0 INTRODUCTION
By letter dated January 27, 1994, Duke Power Company, et al. (the licensee),
for Catawba Nuclear Station, Units 1 and 2, proposed changes to surveillance requirements (SR) 4.6.3.2 and 4.9.4.1 for Technical Specifications (TS) 3/4.6.3 " Containment Isolation Valves," and 3/4.9.4, " Containment Building Penetrations." Specifically, the licensee proposed elimination of the humidity control function of the containment purge (VP) system humidistats by suggesting the following changes to SR 4.6.3.2 and 4.9.4.1:
l l
SR 4.6.3.2 Deletion of the requirement for periodic verification of VP isolation on high l
relative humidity (RH) isolation test signal. The subject verification requirement is worded as follows in the existing TS:
"d.
Verifying that on a High Relative Humidity (270%) isolation test signal, each upper and lower containment purge supply and exhaust valve actuates to its isolation position."
SR 4.9.4.1 Revision of the existing SR which is given below "4.9.4.1 Each of the above required containment building penetrations shall be determined to be either in its closed / isolated condition or exhausting through an OPERABLE Reactor Building Containment Purge System with the capability of being automatically isolated upon heater failure within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> prior to the start of and at least once per 7 days during CORE ALTERATIONS or movement of irradiated fuel in the containment building by:
a.
Verifying the penetrations are in their closed / isolated condition, or b.
Verifying the upper and lower containment purge supply and exhaust valves close upon a High Relative Humidity test signal."
l 9406030122 940525 DR ADOCK 05000413 PDR
. as follows:
"4.9.4.1 Each of the above required containment building penetrations shall be determined to be either in its closed / isolated condition or exhausting through an OPERABLE Reactor Building Containment Purge System within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> prior to the start of and.at least once per 7 days during CORE ALTERNATIONS or movement of irradiated fuel in the containment building by:
a.
Verifying the penetrations are in their closed / isolated condition, or b.
Exhausting through an OPERABLE Reactor Building Containment Purge System."
Contingent upon NRC approval of the above proposed TS change, the licensee has plsnned to implement a plant modification involving VP system control wiring changes to remove the humidistats from the control circuits for both units.
The licensee provided justification for the proposed TS changes. The staff's evaluation of the proposed TS changes is given below.
2.0 EVALVATION The VP system filtration units include electric duct heaters located upstream of the filter trains.
These heaters raise the temperature of the air stream entering the carbon adsorber in the filter train to limit the relative humidity (RH) of the air stream to less than 70 percent. The original basis for limiting the RH of the influent air stream to less than 70 percent by-using the heaters was to assure that the adsorber would perform with removal efficiencies for radiciodine in elemental and organic-forms no less than what I
were used for these forms in the' design basis accidental analysis. As stated i
in the January 27, 1994, licensee's submittal, the original basis for the humidistats was to ensure that the VP system filter trains operated within the TS limits, i.e., the RH for the air stream cntering the adsorber was s 70%.
The humidistats ensured the above basis was met through their control function which would result in automatic termination of the VP system operation when 1
the humidistats would sense RH 2 70% in the air stream entering the adsorber, indicating a possible heater failure.
Technical Specification Amendment Nos. 90 and 84 to TS 3/4.9.4 for Units 1 and 2, respectively, revised carbon adsorber testing requirements to 95% RH equilibrium conditions by incorporating carbon adsorber testing procedures in accordance with ASTM D3803-1989. The subject procedure is a' stringent carbon adsorber testing procedure that assumes no heater to limit the RH of the influent air stream through the carbon adsorber test sample to less than 70%.
These tests are conducted periodically to validate the iodine removal efficiencies used in the design basis accident analysis.
The revised TS thus allow the carbon adsorbers to experience RH levels higher than 70% and still l
remain within their analyzed conditions.
Since the design basis filter efficiencies can be met for the VP systems using a test method that assumes no heaters, the above TS amendments include " ACTION" statements to imply that the VP system operability no longer depends upon heater operability.
However, to
.' provide additional margin to carbon adsorber performance, the amended TS include SR to ensure heater operability.
Further, the amer.ded TS include
" ACTION" statements which call for restoring an inoperable heater to operable status within 7 days or file a special report within 30 days specifying the reason for heater inoperability and planned actions to return it to operable status.
As justified in the licensee's submittal dated January 27, 1994, the revised carbon adsorber SR and heater ACTION statements per TS Amendment Nos. 90 and 84 for Units 1 and 2, have effectively precluded the control function served by the VP system humidistats and are, furthermore, a logical follow-up of the already NRC approved TS Amendment Nos. 90 and 84 for Units 1 and 2, respectively.
It should also be noted that the proposed TS changes do not impact the isolation of the VP system on high radiation signal.
Based on the above findings, the staff concludes that the licensee's proposed changes to SR 4.6.3.2 and 4.9.4.1 for Units 1 and 2 TS 3/4.6.3 and 3/4.9.4, as shnwn in the licensee's January 27, 1994, submittal, are acceptable.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the South Carolina State official was notified of the proposed issuance of the amendments. The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
The amendments change surveillance requirements.
The NRC staff has determined that the amendments involve 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 amendments involve no significant hazards consideration, and there has been no public comment on such finding (59 FR 10005 dated March 2, 1994). Accordingly, the amendments meet the eligibility criteria for categcrical 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 amendments.
5.0 CONCLUSION
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 l
activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendments will not be inimical to the common l
defense and security or to the health and safety of the public.
Principal Contributor:
T. Chandrasekaran Date: May 25, 1994 j
l
. _ - - _ _ - -