ML19338C955

Forwards IE Circular 77-14, Separation of Containment Water Sys from Noncontaminated Plant Sys. No Response Required

ML19338C955
Person / Time
Site:	Dresden, Byron, Braidwood, Quad Cities, Zion, LaSalle
Issue date:	11/28/1977
From:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:	Brian Lee COMMONWEALTH EDISON CO.
References
NUDOCS 8009100929
Download: ML19338C955 (1)

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NOV 2 81977 1

i Docket No. 50-456, 50-457 Docket No. 50-454, 50-455

' Docket No. 50-29. 50-304 Docket No. 50-

, 50-374 Docket No. 5 50-237, 50-249 l

Docket No. 50-254, 50-265 1

Cosmonwealth Edison Company AITN:

Mr. Byron Lee, Jr.

Vice President Post Office Box 767 Chicago, IL 60690 Centlement l

The enclosed IE Circular No. 77-14 is forwarded to you for infor-i nation. No written response is required.

Should you have any i

questions related to your understanding of this matter, please i

contact this office.

Sincerely, t

- I James C. Keppler j

Director i

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Enclosures:

l 1.

IE Circular No. 77-14 l

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List of IE Circulars Issued in 1977 cc w/encle:

Mr. R. Cosaro, Project Superintendent Mr.' Cunner Sorensen, Site Project Superintendent Mr. N. Wandke, Plant i

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November 28, 1977 IE Circular No. 77-14 SEPARATION OF CONTAMINATED WA,TER SYSTEMS FROM NONCONTAMINATED PLANT SYSTEM This circular describes an event which occurred at a nuclear power facility; however, the generic implications may be applicable to test reactors, fuel cycle f acilities, and major byproduct material processors.

In June 1977, the licensee for Beaver Valley 1 reported that makeup water from a primary water storage tank (PWST) contaminated the plant water treatment system, which in turn supplies the in-plant domestic (potable) water system. The plant domestic water became contaminated with a tritium concentration of 7xE(-3) uCi/ml. The domestic water was contaminated for approximately six hours before the condition was detected by the licensee and controls were established over the use of in-house water. No significant exposure of plant personnel resulted from the event; however, five individuals showed positive levels of tritium by urinalysis. No release to the offsite environment above maximum permissible occurred.

The PWST receives processed reactor coolant water from the Boron Recovery System which has been purified through evaporation, degasi-fication and demineralization to remove radioisotopes other than tritium. The PWST is used to supply primary grade water to the reactor coolant system and is normally kept separated from the water treatment system. The cross connection between the primary grade water system and the water treatment system occurred when an isolation valve was inadvertently lef t open during valve line-up operations to recirculate the PWST. The procedure which specified the required line-up was being used for the first time since preoperational testing and did not list the subject valve.

In addition to the valving error, however, a design error resulted in connecting a line from the PWST to a water treatment system line at a position upstream of two teries stop-check valves.

In the proper configuration, the line would have been connected downstream of the stop-check valves, which would have prevented back flow of water from the primary grade water system to the water treatment system even with the isolation valve left open.

Corrective actions taken 1

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IE Circular No. 77-14 2.-

November 28, 1977 by the licensee were to:

(1) correct identified procedural deficiencies which led to the valving error; (2) modify the piping installation to the intended configuration; and (3) add two series isolation valves upstream or the stop-check valves in a "tell-tale" arrangement to provide an air break between the primary water and water treatment lines. The above corrective actions are being reviewed for suit-ability with design separation criteria.

Section 10.5.3 of the National Standard Plumbing Code requires double check valves of siphon breaker between potable and nonpotable systems.

Section 9.2.4 of the Standard Review Plan (NUREG-75/087) states that the acceptance criteria for design of the potable and sanitary water systems (PSWS) is acceptable if there are no interconnections between the PSWS and systems having the potential for containing radioactive materials.

A somewhat similar incident had previously occurred in March 1975 at Millstone Units 1 and 2 when an improperly wired conductivity cell instrument permitted the return of high activity water to the house heating boiler makeup system. Overflow from the deaerating feed tank and surge tank, which are components of the house heating boiler makeup system, resulted in an unfiltered and unmonitored release of contaminated water.

It is recommended that you review your systems and as-built (or design) drawings, identify all interconnections between contaminated and non-contaminated water systems, and review the interconnection design to assure that separation has been provided. Operating procedures which could lead to inadvertent contamination of domestic water systems should be reviewed to verify that proper valve lineup and administrative controls are provided to prevent contamination of the domestic water supply and the subsequer.t intake of radioisotopes by plant personnel.

No written response to this Circular is required. Your review of this matter to determine its applicability to your facility and any correc-tive and preventive actions taken or planned, ar appropriate, will be reviewed during a subsequent NRC inspection.

If you desire additional information regarding this matter, contact the Director of the appro-priate NRC Regional Of fice.

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O IE Circular No. 77-14 November 28, 1977 LIST 1hG OF IE CIRCULARS ISSUED IN 1977 CIRCULAR SUBJECT FIRST DATE OF ISSUED TO NO.

ISSUE 77-01 Malfunctions of 1-4-77 All holders of Limitorque Valve Operating Licens Operators (OL) or Construe tion pernit(CP) 77-02 Potential Heavy 2-15-77 All affected Spring Flooding holders of OLs77-02A Potential Heavy 2-16-77 All affected Spring Flooding holders of cps 77-03 Fire Inside 2-28-77 All holders of a Motor Control OLs and cps Center 77-04 Inadequate Lock 3-17-77 Safeguard Group Assenblies I, II, IV, V, Licensees 77-05 Liquid Entrapment 3-24-77 All holders of in Valve Bonnets OLs and cps 77-06 Effects of Hydraulic 4-1-77 All holders of Fluid on Electrical OL's and cps Cable 77-07 Short Period During 4-12-77 Holders of Reactor Startup B'a'R OLs 77-08 Failure of Feedwater 4-13-77 All holders Sample Frobe of OLs 77-09 Improper Fuse 5-25-77 All holders of Coordination In BWR BWR OLs or cps Standby Liquid Control Systec Control Circuits 77-10 Vacuun Conditions 7-15-77 All holders of Resulting in Datage to OLs Liquid T:secss Tanks D**b]D

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IE Circular No. 77-14 November 28, 1977 LISTING OF lE CIRCULARS ISSUED IN 1977 (Continued)

CIRCULAR SUBJECT FIRST DATE OF ISSUED TO NO.

ISSUE 77-11 Leakage of Con-9-6-77 All holders of OLs tainment Isolation and cps Valves with Resilient Seats 77-12 Dropped Fuel Asscc-9-15-77 All helders of BWR blies at EWR Facili-OLs or cps ties 77-13 Reactor Safety Signals 9-22-77 All holders of OLs.

Negated During Testing and cps 1

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