ML20245F579
| ML20245F579 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 08/04/1989 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20245F578 | List: |
| References | |
| NUDOCS 8908140420 | |
| Download: ML20245F579 (3) | |
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l SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 134 TO FACILITY OPERATING LICENSE N0. NPF-3 TOLEDO EDISON COMPANY AND THE CLEVELAND ELECTRIC ILLUMINATING COMPANY DAVIS-BESSE NUCLEAR POWER STATION, UNIT NO. 1 DOCKET NO. 50-346
1.0 INTRODUCTION
In its letter dated January 15, 1988, the Toledo Edison Company (the licensee) requested an amendment to the operating license for the Davis-Besse Nuclear Power Station, Unit No. I to delete, in its entirety, Sections 3/4.3.3.7, Chlorine Detection Systems, from Appendix A to the license, Technical Specifi-cations. The sections to be deleted include the Limiting Condition for Opera-tion, the Action Statement, the Surveil 7ance Requirements and the Basis Section.
The subject amendment application also requested that the Index in Appendix A be updated to reflect this change.
2.0 EVALUATION The purpose of the chlorine detection system at the Davis-Besse facility is to provide an alarm and to automatically isolate the control room in the event that a chlorine concentration of 5 parts per million (ppm) or more is present.
This system was required since the licensee previously stored chlorine in its gaseous elemental forin on-site in a single 30-ton railroad tank car about 300 yards north of the turbine building. The chlorine in this tank car and in the piping from the tank car was the assumed chlorine source in the accident analysis in Chapter 15 of the Updated Safety Analysis Report (USAR). The licensee also kept chlorine on-site in 12150-pound cylinders in the water treatment building.
The chlorine detection system was designed and installed in accordance with the NRC guidelines contained in R aulatory Guides 1.78 and 1.95.
The principal criterion governing the design of this system was the limitation stated in Regulatory Guide 1.78 that the chlorine concentration in the control room should not exceed 15 ppm by volume within 2 minutes after the operators are made aware of the presence of chlorine.
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The licensee'has removed the two on-site sources for a potential release of chlorine cited above.
Instead, the licensee now uses a 15-weight-percent sodium hypochlorite (Na0C1) solution to control algae and slime in the on-site water systems. This sodium hypochlorite solution is stored in tanks at two separate locations. One of these is used in the circulating water system while the other is used in the makeup water treatment system.
It is possible that significant quantities of gaseous chlorine could be released on-site from either of the two sodium hyochlorite systems cited above by means of a chemical reaction. This release could be caused by the interaction of the sodium hypochlorite solutions with either an acid, ammonia, a detergent or any substance with a low pH (i.e., acidic in nature). While these substances are stored on-site, inty are physically separated from the sodium hypochlorite solutions. Moreover, a near simultaneous rupture of one of the sodium hypo-chlorite systems and a system containing a solution capable of chemically releasing gaseous chlorine (e.g., an acid or ammonia) plus a mechanism for bringing both substances into contact is required to generate chlorine.
Additionally, both sodium hypochlorite tanks have dikes surrounding them capable of storing 110 percent of the tank volumes.
It is highly improbable that gaseous chlorine would be released from either of the two tanks containing sodium hypochlorite solutions considering the various factors required to bring two chemical solutions together capab'e of releasing gaseous chlorine. These factors are: (1) the near simultaneous rupture of two separate systems; (2) a drainage path connecting the two substances; and (3) failure or overtopping of the dike. Accordingly, the staff finds that the on-site release of gaseous chlorine from either of the two sodium hypochlorite systems need not be considered.
With respect to off-site sources of chlorine, the licensee determined that chlorine is not routinely shipped nor manufactured near the Davis-Besse facility. The licensee did, however, identify a site about 3 miles from the Davis-Besse site where chlorine is stored in six 150-pound cylinders.
This storage site is the Erie Industrial Park Water Treatment Facility.
Had this storage site been situated at 5 miles, or greater, from the Davis-Besse facility, this limited quantity of chlorine need not have been considered per the NRC guidance in Regulatory Guide 1.78.
The licensee therefore calculated that an accidental release of this chlorine could, under certain meteorological conditions, result in a maximum chlorine concentration at the Davis-Besse control room air intake of about 6 ppm.
Since this concentration is only at the center of the potential plume of gaseous chlorine, the average concentration would be significantly less.
Furthermore, the meteorological conditions required to achieve this concentra-tion (i.e., wind direction and low velocity) represent a low probability.
More importantly, this maximum chlorine concentration of 6 ppm is below the guideline limit for control rooms of 15 ppm as stated in Regulatory Guide 1.78.
Since chlorine would be readily detectable by the control room operators at levels of 1 to 3 ppm, there would be ample opportunity for the control room
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. operators to take action. This would include manually isolating the control room. This capability of manually isolating the control room air intake is independent from the chlorine detection system and will remain in place after deletion of the chlorine detection system.
The staff agrees with the lictnsee that there is neither an on-site nor nearby off-site source of potential chlorine release which could result in a chlorine concentration at the Davis-Besse control room air intake requiring automatic control room isolation. On this basis, the staff concludes that the present chlorine detection system is no longer required. Accordingly, the proposed deletion of Sections 3/4.3.3.7, including Section 3/4.3.3.7 in the Bases, from the Appendix A to the Davis-Besse operating license is acceptable.
3.0 ENVIRONMENTAL CONSIDERATION
This amendment involves a change to a requirement with respect to the installation or use of a facility component located withir the restricted area as defined in 10 CFR Part 20 or a change to a surveillance requirement. 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 expo:;ure. The Commission has previously issued a proposed finding that this amendment involves no significant hazards consideration, and there has been no public comment on such finding. Accordingly, this amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuantto10CFR51.22(b),noenvironmentalimpact L
statement nor environmental assessment need be prepared in connection with the issuance of this arendment.
4.0 CONCLUSION
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The staff 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, and (2) such activities will be conducted in compliance with the Commission's regulations, and the l
issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
M. D. Lynch Dated:
August 4, 1989 1
D August 4 1989 0
Docket No. 50-346 DISTRIBUTION Docket File c BGrimes NRC & Local PDRs TMeek(4)
PD33 Gray File Wanda Jones Mr. Donald C. Shelton MVirgilio JCalvo Vice President, Nuclear PKreutzer ACRS(10)
Toledo Edison Company TWambach GPA/PA Edison Edison Plaza - Stop 712 OGC-WF1 ARM /LFMB 300 Madison Avenue DHagan PDIII-3 r/f Toledo, Ohio 43652 EJordan JHannon MDLynch
Dear Mr. Shelton:
(TAC NO. 66734)134TO FACILITY OPERATING LICENSE NO
SUBJECT:
AMENDMENT NO.
The Consission has issued Amendment No.134 to Facility Operating License No.
NPF-3 for the Davis-Besse Nuclear Power Station, Unit No.1.
The amendment revises the Technical Specifications in response to your application dated January 15, 1988.
This amendment deletes Sections 3/4.3.3.7, Chlorine Detection Systcms, from Appendix A, Technical Specifications, and Section 3/4.3.3.7 from the Bases.
The index in Appendix A has also been updated to reflect this deletion.
A copy of the Safety Evaluation is also enclosed. Notice of issuance will be included in the Commission's next biweekly Federal Register notice.
Sincerely, Original signed by Thomas V. Wambach, Sr. Project Manager Project Directorate III-3 Division of Reactor Projects - III, IV, V & Special Projects Office of Nuclear Reactor Regulation
Enclosures:
1.
Amendment No.134 to License No. NPF-3 2.
Safety Evaluation cc: See next page Y
Office:
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