ML16138A811
| ML16138A811 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 04/02/1996 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML16138A810 | List: |
| References | |
| NUDOCS 9604080222 | |
| Download: ML16138A811 (6) | |
Text
UNITED STATES S, 0 NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-4001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 215 TO FACILITY OPERATING LICENSE NO. DPR-38 AMENDMENT NO. 215TO FACILITY OPERATING LICENSE'DPR-47 AND AMENDMENT NO. 212TO FACILITY OPERATING LICENSE DPR-55 DUKE POWER COMPANY OCONEE NUCLEAR STATION, UNITS 1. 2. AND 3 DOCKET NOS. 50-269, 50-270, AND 50-287
1.0 INTRODUCTION
By letter dated April 2, 1996, Duke Power Company (the licensee) submitted an emergency request for changes to the Oconee Nuclear Station, Units 1, 2, and 3 Technical Specifications (TS).
The requested changes would revise TS 4.5.4 and 4.14 relating to Surveillance Requirements for charcoal filter laboratory testing related to the testing methodology used to determine operability of the charcoal filters in the penetration room ventilation system (PRVS),
reactor building purge filters, and spent fuel pool ventilation system (SFPVS).
Currently, the licensee tests charcoal in these systems in accordance with ASTM D 3803-1989, "Standard Test Methods for Radioiodine Testing of Nuclear-Grade Gas-Phase Adsorbents." Although this method of testing provides more accurate assurance that these ventilation systems will perform their design function, it is inconsistent with the requirements of the TS.
Therefore, the proposed emergency amendment modifies the TS to reflect the current testing methodology.
2.0 EVALUATION The proposed amendment changes the testing requirements in the TS used to determine the operability of the charcoal in PRVS, SFPVS, and the reactor building purge system. The charcoal is provided to remove iodine from the air as it passes through these systems. There are no changes to the physical design or operation of the facility. TS Bases, and Updated Final Safety Analysis Report (FSAR) design bases are not affected.
American National Standards Institute (ANSI) N510-1975, "Nuclear Power Plant Air Cleaning Units and Components," and applicable American Society for Testing and Materials (ASTM) D 3803-1979 (Method C), "Standard Method for Radioiodine Testing of Nuclear-Grade Gas-Phase Adsorbents," presently form the licensing basis test requirements. The essential elements of this test are:
9604080222 960402 PDR ADOCK 05000269 P
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- 95% Relative Humidity (RH)
- A pre-test charcoal sample equilibration for temperature at 1300 C only
- A test medium temperature of 1300 C
- A challenge for one hour and a post-test sweep for four hours at 1300 C and 95% R.H.
- Methyliodide penetration of less than 10 percent The essential elements of the proposed TS change are those required by ASTM D 3803-1989, "Standard Test Methods for Radiation Testing of Nuclear-Grade Gas Phase Adsorbents." ASTM D 3803-1989 is updated guidance based on revising the ASTM D 3803-1979 standard in corformance with the justification noted in NRC Information Notice (IN) 87-32 and EGG-CS-7653 (Contractor's Technical Evaluation Report for the NRC/INEL Activated Carbon Testing Program).
The essential elements of the proposed TS change for testing per ASTM D 3803 1989 (Method A for used charcoal) are:
- 95% relative humidity (RH) for the charcoal samples
- Pre-test charcoal sample equilibration for humidity
- Equilibration of the sample for 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br /> (16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> unmonitored and 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> monitored) at 300 C and 95% RH
- Elution for 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> at 30' C and 95% RH
- Challenge for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> at 300 C and 95% RH
- Methyliodide penetration of less than 10%
The differences between the current TS and the proposed TS change requirements for charcoal testing are:
- A test temperature of 130*C versus 30*C
- No pre-test humidity equilibration versus a pre-test humidity equilibration
- Temperature equilibration of the test charcoal to the test air temperature
- A one-hour challenge and a four-hour post-test sweep versus a one-hour challenge and a one-hour post-test sweep These differences will be addressed individually and the proposed change will be shown to be more conservative than the present TS requirement.
The quantity of water retained by charcoal (carbon) is dependent on temperature. Generally, the higher the temperature, the less water retained.
The water retained by the charcoal decreases the efficiency of the charcoal to adsorb other contaminants. At 300C and 95% RH, carbon will retain about 40 weight percent water. At 130'C and 95% RH, charcoal retains only about 2 to 3 weight percent water. Therefore, the lower temperature test medium of the proposed TS will yield more conservative results than present TS.
Pre-test humidity equilibration is achieved by sweeping air of the appropriate humidity through the test charcoal.
This condition is for testing new charcoal and until 1977 it also was applied for testing used charcoal.
In 1977, RDT M16-1T-1977 was released stating that for testing used carbon, "the
-3 material shall not be pre-equilibrated before testing."
NUREG/CR-0771, "Effects of Weathering on Impregnated Charcoal Performance," May 10, 1979, provides a basis by stating that, "it is thought that the elimination of the pre-humidification is a better simulation of accident conditions since a charcoal filter must be ready at all times...."
It also states that, "several investigators do not recommend any pre-treatment (of the carbon) in order to prevent a partial regeneration of the carbon which would increase the measured trapping efficiency." Therefore, by the release of the 1979 ASTM 0 3803, it was established that the better test method was not to pre-equilibrate the humidity of the charcoal.
The present TS reference to N510-1975 (ASTM D 3803-1979, Method C) requires the charcoal to be equilibrated to 130'C and 95% RH.
The methyliodide test medium would then be introduced at 130*C. Charcoal testing is not performed this way because this would cause condensation to form on the charcoal (the dew point temperature of the test medium at these conditions is approximately 71'C. Condensation on the charcoal sample itself ("wetting the bed") results in the test being invalid. This is supported by paragraph 12.41. of ASTM 0 3803-1989 which states with respect to relative humidity of the test medium that, "tests at saturation or above give very erratic results."
Because of this, the testing standards after 1976 (i.e., ASTM 0 3803-1979, ASTM D3803 1989, N509-1980), have been changed to include pre-test thermal equilibration at the test temperature.
The post-test sweep of the charcoal is performed to evaluate the ability of the charcoal to hold the adsorbate once it is captured. The current TS test specifies a four-hour test at 130 0C. The proposed TS change will use a one hour sweep at the test medium temperature of 30'C. The lower temperature bounds the design basis conditions realistically by yielding more conservative results.
The requested changes revise TS 4.5.4 and 4.14, relating to Surveillance Requirements for charcoal filter laboratory testing, such that existing flawed test methodology in the TS will reflect the currently utilized acceptable test methodology in accordance with industry standards. The staff has evaluated this change and concludes that the testing methodology proposed by the licensee adequately demonstrates the operability of the penetration room ventilation system, the reactor building purge filters and the spent fuel pool ventilation system and is therefore acceptable.
3.0 EMERGENCY CIRCUMSTANCES In its April 2, 1996, application, the licensee requested that this amendment be treated as an emergency amendment. In accordance with 10 CFR 50.91(a)(5),
the licensee provided the following information regarding why this emergency situation occurred and how it could not have been avoided.
While performing an analysis of safety related ventilation and purge systems, the licensee recognized that the TS requirements for testing the charcoal plenum of these systems is different from that used by the licensee. The TS refers to ANSI Standard N510-1975. The licensee has been using ASTM 0 3803 1989 to meet the TS requirements. The licensee and vendor have determined
-4 that this method of testing better demonstrates the ability of these systems to perform their functions than the test specified in the TS. The licensee promptly reported this condition to the NRC, requested the emergency amendment to correct this discrepancy and avoid an unnecessary plant shutdown of Oconee Units 1 and 3, and prevention of defueling of Oconee Unit 2.
The licensee recognizes that NRC Information Notice (IN) 87-32, "Deficiencies in the Testing of Nuclear-Grade Activated Charcoal," dated July 10, 1987, identified that serious problems existed with the testing capabilities of many of the testing companies and the testing standards. All areas were vendor specific. Guidance to licensees was to seek direct contact with the individual testing companies to improve test accuracy. INEL report EGG-CS-7653, referenced in IN 87-32, recognizes Nuclear Containment Systems, Inc. (NCS), the vendor used by Oconee Nuclear Station, as one of the few vendors whose laboratory performance meets NRC criteria. They were also determined to fully satisfy the licensee's Vendor Quality Assurance Program.
IN 87-32 further identified serious shortcomings with the Standard (RG 1.52, Revision 2) which has not been revised since 1978. Based on the information provided in IN 87-32, the licensee took action to verify the test methodology and accuracy. The IN did not cause the licensee to review the TS for any needed changes.
The licensee identified the inconsistency between their existing practice and the TS requirements, and promptly notified the NRC and proposed this emergency amendment to resolve the inconsistency. As a result of prior information about problems with the testing of charcoal, the licensee took action to ensure that the testing done to support operation of Oconee.Units 1, 2, and 3 was conservative. Absent relief from the NRC, a plant shutdown would be required for Oconee Units 1 and 3, and for Oconee Unit 2, would prevent startup, since testing not consistent with TS requirements would result in the equipment being declared inoperable.
The staff concludes that an emergency condition exists in that failure to act in a timely way would result in shutdown of Oconee Units 1 and 3, and prevent the return to power of Oconee Unit 2. In addition, the staff has assessed the licensee's reasons for failing to file an application sufficiently in advance to preclude an emergency, and concludes that the licensee identified the deficiency in the TS, promptly notified the staff of the deficiency, and promptly proposed this amendment to remedy the situation. Thus, the staff concludes that the licensee has not abused the emergency provisions by failing to make timely application for the amendment. Thus, conditions needed to satisfy 10 CFR 50.91(a)(5) exist, and the amendment is being processed on an emergency basis.
4.0 FINAL NO SIGNIFICANT HAZARDS CONSIDERATION
DETERMINATION The Commission's regulations in 10 CFR 50.92(c) state that the Commission may make a final determination that a license amendment involves no significant hazards consideration if operation of the facility in accordance with the amendment would not:
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(1) Involve a significant increase in the probability or consequences of an accident previously evaluated; or, (2) Create the possibility of a new or different kind of accident from any previously evaluated; (3) Involve a significant reduction in a margin of safety.
The proposed changes do not involve a significant hazards consideration, because operation of the Oconee Nuclear Station in accordance with the proposed change would not:
- 1. Involve a significant increase in the probability or consequences of an accident previously evaluated.
The charcoal testing protocol changes will not affect system operation or performance, nor do they affect the probability of any event initiators.
These changes do not affect the setpoints for actuation of the ventilation systems or accident mitigation capabilities. Therefore, the proposed changes will not significantly increase the consequences of an accident or malfunction of equipment important to safety previously evaluated in the Final Safety Analysis Report (FSAR).
- 2. Create the possibility of a new or different kind of accident from any previously evaluated.
The changes to the charcoal sample testing protocol will not affect the method of operation of the system. The proposed changes only affect the testing criteria for the charcoal samples. No new or different accident scenarios, transient precursors, failure mechanisms, or limiting single failures will be introduced as a result of these changes. Therefore, the possibility of a new or different kind of accident other than those already evaluated will not be created by these changes.
- 3. Involve a significant reduction in a margin of safety.
The new charcoal adsorber sample laboratory testing protocol more accurately demonstrates the required performance of the adsorbers in the Penetration Room Ventilation System (PRVS), Reactor Building Purge Filters, and Spent Fuel Pool Ventilation System (SFPVS), following a design basis Loss of Coolant Accident (LOCA) or in the Reactor Building Exhaust following a fuel handling accident outside containment. The change in charcoal sample testing protocol will not affect system performance or operation. The decontamination efficiencies used in the offsite and control room dose analyses are not affected by this change.
Therefore, no offsite and control room dose analyses are affected by this change, and all offsite and control room doses will remain with the limits of 10 CFR Part 100. Thus, these changes will not result in a significant reduction in any margin of safety.
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5.0 STATE CONSULTATION
In accordance with the Commission's regulations, the South Carolina State official (David King) was notified of the proposed issuance of the amendment.
The State official had no comments.
6.0 ENVIRONMENTAL CONSIDERATION
S The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and change surveillance requirements. The NRC staff has determined that the amendment involves no significant increase in the amounts, and no significant changes in the types, of any effluent that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. 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. The Commission has made a final no significant hazards finding with respect to this amendment.
7.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, that: (1) the amendment does not (a) significantly increase the probability or consequences of an accident previously evaluated, (b) increase the possibility of a new or different kind of accident from any previously evaluated or, (c) significantly reduce a margin of safety and, therefore, the amendment does not involve a significant hazards consideration; (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner; (3) such activities will be conducted in compliance with the Commission's regulations; and (4) 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:
Len Wiens Date:
April 2, 1996