IR 05000295/1987018
| ML20237H221 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 08/17/1987 |
| From: | Greger L NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20237H204 | List: |
| References | |
| 50-295-87-18, 50-304-87-20, NUDOCS 8708240397 | |
| Download: ML20237H221 (4) | |
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I U.S.. NUCLEAR REGULATORY COMMISSION
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REGION III-
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Reports'No. 50-295/87018(DRSS); 50-304/87020(DRSS)
Docket-Nos. 50-295; 50-304 Licenses No. DPR-39; No. DPR-48 Licensee: ~ Commonwealth Edison Company P. O. Box 767 Chicago, IL 60690
Facility Name:
Zion Nuclear Power Station, Units 1 and 2 Meeting At:
Region III Office, Glen Ellyn, Illinois Meeting Conducted:
July 15, 1987
Approved By:
L. Robert e er, Chief 8-/7-87 Facilities Radiation Protection Date Section Meeting Summary-Meeting on July 15, 1987 (Reports No. 50-295/87018(DRSS);
No. 50-304/87020(DRSS))
Areas Discussed:
An enforcement meeting conducted to discuss an event in which a release of airborne radioactivity into the auxiliary building resulted in airborne radioactivity entering the control room and the implications of that event on operability of the control room ventilation system.
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Meeting Attendees Commonwealth Edison Company
C. Reed, Senior Vice President, Nuclear Operations K. Graesser,. General Manager PWR Division i
L. Butterfield, Nuclear Licensing Manager I
D. Farrar, Technical Services Manager.
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M. Turbak, Operating Plant Licensing Director T. Rieck, Zion Technical Services Superintendent
P. LeBlond, Zion Nuclear Licensing Administrator F. Lentine, Zion Project Engineer, SNED G. Lahti, Assistant Head, NSLD, Sargent & Lundy
Nuclear Regulatory Commission - Region III
C. Paperiello, Deputy Regional Administrator J. Grobe, Director, Enforcement and Investigation Coordination Staff
W. Shafer, Chief, Emergency Preparedness and Radiation Protection Branch i
W. Forney, Chief, Project Branch No. 1 L. Greger, Chief, Facilities Radiation Protection Section B. Berson, Regional Counsel W. Schultz, Enforcement Specialist M. Holzmer, Senior Resident Inspector, Zion C. Gill, Senior Radiation Specialist P. Eng, Resident Inspector, Zion
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Nuclear Regulatory Commission - NRR C. Nichols, Senior Reactor Engineer, Plant Systems Branch, DEST C. Willis, Senior Health Physicist, Radiation Protection Branch, DREP 2.
Enforcement Meeting Details The enforcement meeting was held to discuss an event which is described in Inspection Reports No. 50-295/87005(DRSS) and No. 50-304/87005(DRSS).
This event, concerning a release of airborne radioactivity in the auxiliary building which resulted in airborne radioactivity entering the control room, was described by the senior NRC representative.
Although the event resulted in control room operator doses well within regulatory limits, the NRC concluded that this event and subsequent licensee and NRC evaluations showed that the control room emergency ventilation system had been technically inoperable since construction due to an installation error which allowed excessive unfiltered inleakage and therefore
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precluded the system from performing in accordance with its design
requirements.
The concerns discussed by Region III personnel included:
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l Atjt' e time _ of. the. event the control room ventilation system was h'
operating in the accident mode, which should have precluded the radioactive gases entering the control room atmosphere.
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While the inleakage pathway was corrected expeditiously, the inleakage pathway (relief damper backflow) had been in existence since plant construction.
Subsequent to the event, the licensee and the NRC were involved in a
- e-lengthy series _of calculations concerning the potential dose'to.
control room personnel in the event of a design basis accident (DBA)
with the relief: damper'inleakage pathway in. existence.
The NRC position on this matter,'which was provided..to the.-licensee with Inspection Reports No. 50-295/87005 and No. 50-304/87005, is that-the potential dose to control room personnel under DBA conditions would have exceeded the regulatory limits established by General Design Criterion 19 of Appendix A to 10 CFR 50.
In response to the Region III comments, the licensee stated that once discovered the inleakage pathway was promptly corrected and a control ventilation-system walkdown verified the identified relief damper inleakage pathway was the only significant failure to install system components in accordance with design drawings.
The licensee also presented their assessment of the safety significance of the event.
The licensee identified the following completed and planned corrective actions:
Prompt control room ventilation system walkdown and leakage testing
was conducted.
Relief dampers were failed closed, blanked-off, and sealed.
- An extensive system review was conducted.
- Procedures were revised to clearly define appropriate actions if
high radiation is detected in the control room.
Drawings were corrected to reflect the as-built system.
- Performance tests will be conducted at least every 18 months to
verify positive control room pressure with the control room ventilation system in the accident mode.
The control. room ventilation system description will be updated
- after completion of further system enhancements.
The licensee stressed their belief that the NRC enforcement policy requires the severity of enforcement actions to be based on the actual or potential impact on the health and safety of the public.
The licensee stated their dose assessment differed from the NRC analysis primarily because of this belief that the safety assessment of the violations
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.should be based on " realistic" parameters rather than the NRC's. Standard Review Plan (NUREG-0800) assumptions.
The following were, identified by the licensee as'their significant deviations from.the Standard Review Plan (SRP)' assumptions:
Fraction of iodine released - Final Safety' Analysis Report (FSAR)
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design basis-gap release instead of the 50% core release per the SRP.
Containment leak rate - measured bounding.value'(0.035%/ day) instead
of the Technical Specification value of 0.1%/ day.
Atmospheric dispersion / building wake dilution - FSAR design
basis / actual physical configuration instead of the SRP atmospheric dispersion model.
Intake iodine filter performance - FSAR design' basis of 99.99%
efficiency instead of the SRP maximum allowable credit of 99%
efficiency.
Control room personne1' occupancy factor - bounding value from the
licensee's shift manning procedure instead of the SRP assumptions.
The senior NRC representative acknowledged the licensee's presentation and stated that the Region III recommendation concerning enforcement action for the event would be forwarded to the NRC Office of Enforcement for their concurrence.
After review by that Office, the licensee would be notified in writing of the NRC's proposed enforcement action.
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