B11775, Forwards Responses to NRC Questions Re 850819-23 Fire Protection Audit
| ML20133G616 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 10/07/1985 |
| From: | Opeka J NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES |
| To: | Youngblood B Office of Nuclear Reactor Regulation |
| References | |
| B11775, NUDOCS 8510160052 | |
| Download: ML20133G616 (8) | |
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(203) 66s-s000 October 7,1985 Docket No. 50-423 Bil775 Director of Nuclear Reactor Regulation Mr. B. 3. Youngblood, Chief Licensing Branch No. I Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C. 20555 l
Dear Mr. Youngblood:
Millstone Nuclear Power Station, Unit No. 3 Fire Protection Audit During the week of August 19 - 23, 1985, the NRC-NRR Staff, NRC - Region i Staff and its consultants from Brookhaven National Laboratory conducted the fire protection audit for Millstone Unit No. 3. A small number of questions were raised by the NRC-NRR Staff during the audit and the NRC requested Northeast Nuclear Energy Company (NNECO) to provide responses in a timely manner.
l Enclosed are NNECO's responses to these questions.
1 If there are any questions, please contact our licensing representative directly.
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY I
et. al.
BY NORTHEAST NUCLEAR ENERGY COMPANY Their Agent i
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STATE OF CONNECTICUT )
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Then personally appeared before me 3. F. Opeka, who being duly sworn, did state that he is Senior Vice President of Northeast Nuclear Energy Company, an Applicant - herein, that he is authorized to execute and file the foregoing l
information in the name and on behalf of the Applicants herein and that the i
statements contained in said information are true and correct to the best of his 4
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, FIRE HAZARD ANALYSIS / SAFE SHUTDOWN NRC CONCERN The Fire Hazards Analysis does not clearly describe the eftects of fire on safe-shutdown in each fire area.
NNECO RESPONSE The FHA currently states in the " consequences of postulated fire" section that:
The equipment in this area could be destroyed or rendered inoperable; however, due to the redundancy and separation ot equipment, there would be no effect on the safe shutdown of the plant.
This section will be rewritten for each fire area.
The revised wording will state, as a minimum the following information:
This area complies with section C.5.b of BTP CMEB 9.5-1, as documented in the Millstone 3 safe-shutdown analysis.
In the event of a fire in this area, the plant can be safely shutdown using equipment located in separate fire areas.
Where a deviation exists, wording will be as follows:
This area does not comply with the specific requirements of section C.5.b of BTP CMEB 9.5-1.
An alternative means of compliance is provided as described in deviation request number dated NNECO is presently in the process of revising the Fire Hazard Analysis to reflect the above wording.
CO TEST POINTS 2
NRC CONCERN Concerns were expressed regarding the number and locations of the CO concentration measuring probes, which would be used to verify 3
the CO system operability.
2
. CO TEST POINTS (CONTINUED) 2 NNECO RESPONSE Based on past discussions with the Chemetron Test Representative (CO, systen, designer) as well as the NRC Technical Reviewer, NNECO has developed the following CO acceptance test guidelines:
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A minimum of three (3) C0 measuring probes will be 7
utilized in each safety rGlated area protected by CO during testing with the exception of the Cable Spreading Room which will be monitored by six (6) measuring probes during its test.
o The three (3) measuring probes will be installed in each area so that measurements as to the level of CO, present within each area will be taken at a high point near the ceiling, mid point between the floor and ceiling and at a low point within the area.
This arrangement (three (3) different elevations) is a standard test procedure for concentration monitoring of gas fire suppression systems such as Millstone Unit No.
3's.
In addition to the different elevations, the monitoring probes will also be separated / staggered throughout the test area in order to ensu: e that the design concentration levels are uniform thraughout the area.
FIRE AMEA VS. FIRE 20NE NRC CONCERN The difference between fire areas and fire zoner is not clearly explained in the Fila.
NNECO RESPONSE Section 5.4 of the Fire llazards Analysis will be revised as follows:
The plant arrangement is divided into fire areas and fire zones for purposes of conducting the fire hazards analysin and safe-shutdown evaluation.
Fire arers are defined as plant areas l
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. FIRE AREA VS. FIRE ZONE (CONTINUED)
NNECO RESPONSE (CONTINUED) bounded by fire rated assemblies of either 3-hour rated construction or lesser fire resistance as specifically identified and justified in the Fire Hazards Analysis.
Fire zones are zones within fire areas that are used to more thoroughly describe the fire area.
Fire zones may or may not be bounded by fire rated construction.
The safe-shutdown evaluation relies only on fire areas to determine the effects of fire on safe-shutdown.
SPARE CONDUIT SLEEVES NRC CONCERN Capped conduit sleeves through fire barriers were not fire rated assemblies.
NNECO RESPONSE In order to verify the fire integrity at Millstone Unit No. 3's fire barriers in which spare conduit sleeves have been installed, NNECO intends to perform an ASTM E-119 fire test utilizing the spare sleeves.
The fire test of the spare sleeves will be conducted in order to satisfy ASTM E-119/ Branch Technical Position 9.5-1 guidelines regarding fire barrier / penetration seal Acceptance criteria.
Test documentation to verify compliance to the above referenced guidelines will be kept on file by the Licensee for NRC review.
LOCAL ANNUNCIATION NRC CONCERN During the Millstone Unit No. 3 Fire Protection I&E Inspection, a question was asked regarding the lack of local alarm indication lights installed above the floor of the Instrument Rack Room and Computer Room in the Control Building, to locato smoke detectors in alarm beneath the floor area.
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.. LOCAL ANNUNCIATION (CONTINUED)
NNECO RESPONSE NNECO's position regarding the installation of the local alarm indication lights referenced above is as follows:
o Automatic Total Flooding Halon 1301 systems are the primary means of suppression provided for each hazard (i.e.,
Instrument Rack Room and Computer Room underfloor areas).
Alarm location identification above the floor does not enhance the operation or reliability of the total flooding system's (underfloor only) primary means of suppression, o
The Computer Room and Instrument Rack Room detection zones (both underfloor and at the ceiling), in conjunction, with smoke escaping from the underfloor area, provide fire locatitig capability comparable to that achievable with the installation of the above referenced lights.
As stated during the I&E inspection, it is NNECO's intention not to install local alarm indication above the floor, for detection installed beneath the floor, in the Computer Room and Instrument Rack Room of the Control Building.
FIRE DETECTION (OUTSIDE CONTAINMENT)
NRC CONCERN The location, spacing or lack of fire detection in safe shutdown / safety related areas created questions regarding the design criteria used to satisfy NFPA 72E/BTP 9.5-1 guidelines.
Areas of concern were Auxiliary Building, Main Steam Valve Building and Hydrogen Recombiner Building.
NNECO RESPONSE NNECO has recently reviewed the areas of concern regarding the installation of fire detection in safety related/ safe shutdown areas at Millstone Unit No. 3 NNECO has redefined its design criteria so that fire detection coverage will be provided within areas where combustible loading (cables and oils), which could represent a fire hazard, are normally present.
Areas that will not be protected with fire detection coverage will be those areas where combustible loading is not present, i.e.,
cables in conduit or oils contained in valves, piping and tanks which meet the design criteria of NFPA 30.
.. FIRE DETECTION (OUTSIDE CONTAINNENT) (CONTINUED)
NNECO RESPONSE (CONTINUED)
NNECO is presently modifying its fire detection design / installation to address the above design criteria so that its design will satisfy NFPA 72E/BTP 9.5-1 guidelines.
FIRE DETECTION (INSIDE CONTAINNENT)
NRC CONCERN The spacing of fire detectors in Containment does not appear to comply with NFPA 72E.
NNECO RESPONSE NNECO has evaluated this concern and is offering the following:
The Millstone Unit No. 3 Containment (Fire Area RC-1) is a multi-level structure consisting of intermediate levels formed by open gratings.
NFPA 72E requirements for detector spacing in a single level structure call for ceiling mounted detectors on a 30 foot spacing.
Due to the ceiling height and the possibility of smoldering fires because of the sub-atmospheric pressure maintained inside containment, this requirement is not considered to provide the most effective type of detection system for this area.
In accordance with paragraphs 4-3.1.2 and A-4-3.1.2 of NFPA 72E, an engineering survey was performed which recommended placing detectors at various levels of the Containment on the intermediate floor gratings.
To provide a more effective coverage, the detectors are placed at different locations on each level, thereby providing a ' staggered' arrangement as recommended by paragraph A-4-3.1.2 of NFPA 72E.
It is NNECO's position that this arrangement provides a more rapid detection capability, and based upon our engineering evaluation, complies with the alternative detector spacing requirements of paragraph 4-3.1.2 of NFPA 72E.
In addition, since equipment within Containment is monitored in the Control Room, damage to equipment caused by fire will result in direct annunciation / indication of system trouble / failure.
.o 1 FIRE DETECTION (INSIDE CONTAINMENT) (CONTINUED)
NNECO RESPONSE (CONTINUED) i Therefore, it is NNECO's position that the present fire detection system design is adequate for this type of structure and that no further action is required.
NOTE:
This position was reviewed and found acceptable during the Millstone Unit No. 3 Fire Protection Audit in August, 1985.
1 STRUCTURAL STEEL 1
NRC CONCERN Concerns were raised regarding the effects of a fire on the exposed structural steel within the Engineered Safeguards i
Facility Building (ESP).
NNECO RESPONSE NNECO is presently having a computer analysis performed on essential areas within the ESF Building, which demonstrates the effects that a fire would have on unprotected structural steel.
The computer analysis / fire model program is the same fire / structural steel program which was developed by Professional Loss Control Inc. and reviewed and found acceptable by the NRC for Limerick (Philadelphia Electric Co.).
This program / analysis considers the effects of both a total burn-out as well as localized heat concerns.
Based on the results of the analysis, NNECO will take the appropriate steps (fire proofing) to ensure that a fire will not effect the structural stability of the fire barriers within the ESF Building.
It should be noted'that the above approach (fire coating as necessary), based on computer analysis results, is the same approach that was reviewed and found acceptable by the NRC Technical Staff for other areas within Millstone Unit No.
3.
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