ML19290F164
| ML19290F164 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 03/06/1980 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| References | |
| NUDOCS 8003180224 | |
| Download: ML19290F164 (1) | |
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UNITED STATES q
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NUCLEAR REGULATORY COMMISSION
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1990 N. CALIFORNI A BOULEVARD
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- ,,,e WALNUT CRE E K, CAllFORNI A 94596 NEY i' ;;0 Docket ?!o. 50-312 Sacramento Municipal Utility District P. O. Box 15830 Sacramento, California 95813 Attention: Mr. John J. Mattimoe Assistant General Manager Gentlemen:
The enclosed IE Circular is forwarded to you for information.
flo written response to this IE Circular is required.
If you have any questions related to the subject, please contact this office.
Sincerely,
/Dm^0-R. H. Engelken Director
Enclosures:
1.
IE Circular flo. 80-03 2.
List of IE Circulars Recently Issued cc w/ enclosures:
R. J. Rodriguez, SMUD L. G. Schwieger, SMUD 8003iHO*2.'Z.y
SSINS: 6830 Accession fo.:
UNITED STATES 7912190685 NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMEtiT WASHINGTON, D.C.
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March 6, 1980 IE Circular fio. 80-03 PROTECTION FROM T0XIC GAS HAZARDS Chlorine gas releases have been reported at two different reactor facilities in the past two years.
At Millstone, in March 1978, a leak of about 100 standard cubic feet of chlorine (about a gallon of liquid) occurred over a ten minute perico, resulting in the hospitalization or 15 people.
The ventilation system carried the chlorine into the plant buildings, where personnel distress was noted.
No injuries occurred in the buildings due to the small size of the release.
At Browns Ferry, in June 1979, a small leak from a diaphragm on a chlorine reducing valve resulted in the hospitalization of five people, including a control room operator.
Chlorine is highly toxic, producing symptoms after several hours expcsure in concentrations of only one ppm.
Concentrations of 50 ppm are dangerous for even short exposures and 1000 ppm is fatal for brief exposures.
- Chlorine, used at some power stations to control organisms in the circulating water, is normally supplied in one ton containers or in tank cars of up to 90 tons capacity.
Other potential sources of toxic gas that have been identified at nuclear power plants include:
flearby industrial facilities. At Waterford, in July 1979, construction forces had to be evacuated for two and a half hours due to a chlorine gas release from a nearby chemical plant.
Chlorine transportation on adjacent highways, railways and rivers.
Large tanks of aqueous arvonia storef.adr plant buildings.
Both acid and caustic storage tanks located in a common building near the control room. At the Dresden site, in August 1977, accidential mixing of acid and caustic solutions resulted in toxic fumes that entered the control rocm via the ventilation system.
Criterion 19 of Appendix A to 10 CFR 50 requires a control room from which action can be taken to maintain the reactor in a safe condition under accident conditions.
The control room designs in current license applications are
IE Circular No. 80-03 March 6, 1980 Page 2 of 2 reviewed for operator protection from toxic gases (as well as radiation), in 6ccordance with Standard Review Plan (SRP) 6.4 (NUREG 75/087 dated 11/24/75).
Related information on the identification of potential hazards and the evalua-tion of potential accidents can be found in SRP sections 2.2.1-2.2.2 and 2.2.3 respectively. The SRP references Regulatory Guide 1.78 (dated June 1974) on control rocm habitability during chemical releases.
It also references Regulatory Guide 1.95 on requirements for protection against chlorine releases specifically.
The majority of the plants currently operating, however, were built and licensed prior to the development and implementation of this guidance.
A review of some older plants, with respect to toxic gas hazards indicates that they do not have the degree of protection that would be required for present day plants.
Evaluation cf the protection of control rooms from toxic gas releases is part of the systematic evaluation program currently being carried out on certain older plants.
Also, as older facilities submit requests for significant license amendmer.ts, their design features and controls for protec-tion of control rooms are reviewed and, if appropriate, are required to be changed.
However, the recent history of frequent toxic gas release incidents appears to warrant a more rapid implementation of the newer toxic gas protec-tion policies.
For the above reasons, it is strongly recommended that:
You evaluate your plant (s) against section 6.4 and applicable parts of sections 2.2.1-2.2.2 and 2.2.3 of the SRP with respect to toxic gas hazards.
Where the degree of protection against toxic gas hazards is found to be significantly less than that specified in the SRP, provide the controls or propose the design changes necessary to achieve an equivalent level of protection.
No written response to this circular is required.
If you desire additional information regarding this matter, contact the Director of the appropriate NRC Regional Office.
Attachments:
Sections 2.2.1-2.2.2;2.2.3 and 6.4 of NUREG 75/087
IE Circular No. 30-03 Enclosure Parch 6, 1980 RECENTLY ISSUED IE CIRCULARS Ci rcular Subject Date of Issued to No.
Issue 80-02 Nuclear Power Plant Staff 2/1/80 All holders of Reactor Work Hours OLs, including research and test reactors, and cps 80-01 Service Advice for GE 1/17/80 All licensees of Induction Disc Pelays nuclear power reactor operating facilities and holders of nuclear power reactor cps 79-25 Shcok Arrestor Strut 12/20/79 All licensees and Assembly Interference holders of power reactor cps 79-24 Proper Installation and 11/26/79 All Holders of a Calibration of Core Spray Power Reactor OL or Pipe Break Detection CP Equipment on BWRs.
79-23 Motor Starters and 11/26/79 All Power Reactor and Contactors Failed Operating Facilities to Operate and Holders of Reactor cps 79-22 Stroke Times for Power 11/16/79 All Power Reactor Operated Relief Valves Operating Facilities and all Utilities having a CP 79-21 Prevention of Unplanned 10/19/79 All holders of Power Releases of Radioactivity Reactor OLs and cps 79-20 Failure of GTE Sylvania 9/24/79 All holders of Power Relay, Type PM Bulletin Reactor OLs and cps 7305, Catalog SU12-11-AC with a 12V AC Coil 79-19 Loose Locking Devices 9/13/79 All Holders of Power on Ingersoll-Rand Pumps Reactor OLs and cps 79-18 Proper Installation of 9/10/79 All Holders of Power Target Rock Safety-Relief Reactor OLs and cps