ML20212H658

Advises That Removal of Chlorine Monitors from Control Room Intakes Consistent W/Guidelines of SRP Section 6.4 & Therefore,Acceptable.Staff Evaluation Encl

ML20212H658
Person / Time
Site:	Braidwood
Issue date:	03/04/1987
From:	Varga S Office of Nuclear Reactor Regulation
To:	Farrar D COMMONWEALTH EDISON CO.
References
NUDOCS 8703060178
Download: ML20212H658 (5)

Text

og -March 4 1987 ,

.~ Docket Nos. 50-456 '

DISTRI

.and 50-457 . .. a NRC PDR.

. Local _PDR PDf3 Rdg.

T. Novak ~0GC-Mr. Dennis L. Farrar E. Jordan B. Grimes Director of Nuclear Licensing J. Partlow . N. Thompson Commonwealth Edison ~ Company. J. Stevens- C. '. Vogan Post Office Box 767 ACRS_(10)

Chicago, Illinois.60690

SUBJECT:

REMOVAL OF CONTROL ROOM CHLORINE MONITORS By letter dated June 3,1986, the licensee' provided an analysis to demonstrate that the chlorine monitors for the control room intake are not required. Based on the small probability of a chlorine event, the licensee's commitment to

maintain prompt notification communications with the county, the requirement to isolate the control room upon receipt of notice of a toxic gas incident, and the requirement-to demonstrate control room integrity on a routine basis, the staff has determined that the removal of the chlorine monitors from the

-control room intakes is consistent with the guidelines of SRP Section 6.4 and is, therefore, acceptable.

The staff's evaluation is contained in Enclosure 1.- This evaluation will be included in the next SSER publication.

-Steven A. arga, Director

- Project Directorate #3 i

Division of PWR Licensing-A

Enclosures:

l As stated-cc: See next page PDf3 g PDf3 9,D\

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Braidwood Station Mr. Dennis L. Farrar Units I and 2 Comonwealth Edison Company cc: Ms. Lorraine Creek Mr. William Kortier Route.I Box 182 Atomic Power Distribution Manteno, Illinois 60950 Westinghouse Electric Corporation Post Office Box 355 Douglass Cassel, Esq.

Pittsburgh, Pennsylvania 15230 109 N. Dearborn Street Chicago, Illinois 60602 Joseph Gallo, Esq.

Isham, Lincoln & Beale Elena Z. Kezelis, Esq.

1150 Connecticut Ave., N. W. Isham, Lincoln & Beale Suite 1100 Three First National Plaza Washington, D. C. 20036 Suite 5200

• C. Allen Bock, Esq. Chicago, Illinois 60602 Post Offices Box-342 Mr. Charles D. Jones Director Urbana, Illinois 61801 Illinois Emergency Services and Disaster Agency Thomas J. Gordon, Esq.

Waaler, Evans & Gordon 110 East Adams Street Springfield, Illinois 62706 2503 S. Neil Champaign, Illinois 61820 George L. Edgar Newman & Holtzinger, P.C.

Ms. Bridget Little Rorem 1615 L Street, N.W.

l Appleseed Coordinator Washington, D.C. 20036 I 117 North Linden Street Essex, Illinois 60935 Michael Miller, Esq.

Isham, Lincoln & Beale Mr. Edward R. Crass One First National Plaza Nuclear Safeguards and Licensing Division 42nd Floor Sargent & Lundy Engineers Chicago, Illinois 60603 55 East Monroe Street Chicago, Illinois 60603 U. S. Nuclear Regulatory Comission Resident Inspectors Office RR#1, Box 79

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Bracev111e, Illinois 60407 Regional Administrator, Region III U. S. Nuclear Regulatory Comission 799 Roosevelt Road Glen Ellyn, Illinois 60137

I l Enclosura 1 1

SECTION G.4 CONTROL ROOM HARTTABILITY By letter dated June 3,1986, the licensee provided an analysis to demonstrate that the chlorine monitors for the control room intake are not required.

The analysis involved a resurvey of the offsite sources of chlorine within five miles of the station, a calculation of the dispersion of the toxic gas and control room infiltration, and a probability evaluation of the rupture of a chlorine tank car on the Norfolk and Western Railroad.

The licensee's analysis stated that the probability of a chlorine tank car rupture within a 5 mile radius of the plant is significantly less than 10-6 j year.

The licensee's analysis presumed that no toxic gas monitors existed and that the station operator would not don the self-contained breathing apparatus until the chlorine odor was detected (3.5 ppm). The licensee calculated that the concentration existing in the control room 2 minutes after detection would be 13.3 ppm (toxicity is 15.0 ppm). The licensee stated that this allows adequate time for the operators to don self-contained breathing apparatus.

The NRC staff has independently reviewed the probability of a chlorine tank car rupture within the 5 mile radius and calculated the concentration in the control room assuming no toxic gas monitors and detection by odor at 3.5 ppm The staff's analysis of the probability of a chlorine tank car rupture within 5 miles of the Braidwood facility was 1.3 X 10-6 / year, which was a factor of approximately 30 greater than the probability calculated by the licensee. The reason for this disparity was that the licensee calculated the probability of an accident based upon the frequency of chlorine tank car shipments per year and release per car mile (any type).

The calculation should have been based upon the probability of a release per chlorine car mile.

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The staff's analysis also showed that if the licensee was dependent upon the operators to detect the chlorine at a concentration of 3.5 ppm and then to initiate action to protect themselves, than an insufficient period of time exists for the operators to don self-contained breathing apparatus before exceeding toxicity limits. Consequently, with the absence of chlorine monitors, the staff believes that if a release occurs within 5 miles of the Braidwoood facility, the control room should be placed into the isolation mode prior to detection of chlorine odor by the control room operators. This can be accomplished by early notification of a chlorine tank car accident.

By letter dated December 23, 1986, the licensee indicated that representatives from Will County, Illinois have agreed to provide notification to the Braidwood Station in the event of a chlorine accident. The staff believes that this notification process is an acceptable means of alerting the Braidwood Station so that the control room can be isolated. In addition, the station will be required to: include with their control room technical specifications a surveillance requirement to demonstrate on an 18 month basis that the control room envelope can be isolated; and include a procedure to demonstrate, on an annual basis, that control room envelope integrity is j maintained, i.e., infiltration into the control room envelope in the isolation made does not negate the toxic gas analysis and thus, the capability to protect the operators.

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.- Although the probability of a chlorine release occurring is small, compensatory actions are in place which would be utilized to mitigate the consequences of such an event. Based on the small probability of a chlorine event, the licensee's commitment to maintain prompt notification communications with the county, the reouirement to isolate the control room upon receipt of notice of a toxic gas incident, and the requirement to demonstrate control room integrity on a routine basis, the staff has determined that the removal of chlorine monitors from the Braidwood Station control room intakes is consistent with the guidelines of SRP Section 6.4 and is, therefore, acceptable.

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