ML19296B167
| ML19296B167 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 01/23/1980 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19296B163 | List: |
| References | |
| NUDOCS 8002200202 | |
| Download: ML19296B167 (7) | |
Text
",
ENCLOSURE 2 3.0 EVALUATION The following provides our evaluation of the incomplete items.
Numbers in parenthesis following each heading refer to the sections of our previously issued SER which address these incomplete items.
3.1 Cable Spreading Area (3.2.1)
Our SER noted that the licensee would conduct an evaluation to determine a suitable nethod to provide isolation, separation or protection of redundant safety related cables in the cable spreading area.
By letter dated July 31, 1979, the licensee provided an evaluation of the cable spreading room. The licensee proposed a wet pipe sprinkler system in the cable spreading room and fire retardant barriers because of redundant cable exposure.
Our consultant inspected the cable spreading room on August 31, 1979, and the licensee by letter dated October 9,1979, subse-quently agreed to implement the following: (a) combustible penetration damming a:arial be re oved, (b) fire rated dampers be installed in tne two ventilation openings of tne block 'aall separating divisional cabl' ;, (c) fire retardant barriers will be installed to separate recrcan: non-essential cables, and (d) a wet pipe automatic s;-iwier system will be installed for cable tray protection 'n tne 93 x 60 foot area containing a large concentration of cables.
The system will have branc' lines extending from the ceiling with spray heads over the trays. Some areas of the cable spreading room have no crossovers and redundant cables are widely sepa rated.
For those areas, the fire protection will consist of detection and manual suppression.
In the 90 x 60 foot areas of the cable spreading room the licensee cannot confinn what the actual separation between redundant cables important to achieving safe shutdown.
We will require thct alternate shutdown be provided independent of the 90 x 60 foot area.
The above requirement is now included in Appendix R to 10 CFR Part 50 which became effective on We, therefore, expect that the licensee will confonn to this require-ment.
Subject to conformance to this requirement, this item is satisfactorily resolved.
8 0 022 00 2 o a_
i
- 3.2 Protection of Redundant Cable Trays (3.2.2)
Our SER noted that the consequences of fire damage to systems required for safe shutdown would be determined where physical separation of cables in the auxiliary building may not preclude damage to redundant safety related systems.
Fire retardant coatings, automatic sprinklers, suitable fire barriers or early warning detection would be provided to assure that fire danage does not result in a loss of shutdown capability where prompt action is not taken to suppress fires in these areas.
An evaluation of cable routing in the auxiliary building was conducted by the licensee, and the results were submitted by letter dated July 31, 1979. After review of the submittal the adequacy of proposed solutions remained in doubt. A site visit tc specifically examine those areas in question was conducted on August 31, 1979 by our fire protection c:nsul tant. As a result of this visit certain modifications were documeated by letter dated October 9,1979 and clarified
- /.e:ter cated November 21, 1979.
Tne modifications prucosed for the various areas are as follows:
(1) Elevation -45 feet Zone 1 A Column F.8/H.2 and 16.6/17.2 Automatic sprinklers will be provided in the trays to protect crossovers in a balcony area.
Ionization detec-tors will be provided at the ceiling.
The sprinklers will be fed from an adjacent standpipe.
(2). Elevation -45 feet Zone A-1 A Column F.8/H.2 and 17.2/18.4 Ionization detectors will be orovided between Z1 and Z2 trays for the length of the zone.
(3) Elevation -25 feet Zone A-9 Charging Pump Area The general area ionization detectors will provide sufficient early notification to prevent involvement of the adjacent division.
(4) Elevation -5 feet Zone A-18, Column F.3/F.8 and 18.9/19.6 Pipe Penetration Room The cable trays involved in the crossovers will be completely enclosed to prevent fire impingement on the conduits above.
Ionization detectors will also be installed above the trays.
! (5) Elevation -5 feet, Zone A-14, Column F.8/H.2 and 18.1 General ionization detectirn will be provided in the zone with a number of detectors installed at the crossover.
Fire barriers will be inst 111ed above Z14FK10. The clothing storage rack will be relocated to reduce the combustible exposure to safety related cable trays.
(6) Elevation -5 Zone A-14, Columns L.5/M.4 and 17.7 Ionization detectors and barriers will be installed for protection of the Z1 and 22 crossover.
(7) Elevation -5 Zone A-14, Columns M.
and 17.8 Ionization detectors and a barrier between the trays and conduit will be installed to protect the crossover.
(8) Elevation 14 feet 5 inch, Zone A-2
. Column M.7 and 18.9/20.0 The protection of the crossover will consist of both area and tray automatic sprinklers.
The area sprinklers will extend 15 feet into fire Zone 1-270.
General area protection will also be provided ir, the vicinity of the crossover.
(9) Elevation 14 feet 6 inch, Zone A.24, Column H.2/H.4 and 17.1/17.5 A general area detection system with specific detectors located at the tray crossovers will be installed and where the tray stacks run parallel with one another.
Fi.e barriers will also be providec at these crossovers.
(10) Elevation -14 feet 6 inch Zone A-24, Column F.8/H.2 and 17.4 Ionization cetectors will be proviced over the crossovers and the trays involved will be totally enclosed from column line 16.6 to 17.7.
In several of the above listed areas either the separation is not adequate to assure safe shutdown or the information available is not adequate to determine the impact of a fire on safe shutdown.
, For these areas, we will require alternate shutdown as follows:
(a) Auxiliary Building Zone 1 A, Column F.8/H.2 and 16.6/17.2 elevation -45.
(b) Auxiliary Building Zone A-24, Columns F.8/H.2 and 17.4 elevation 14'-6".
(c) Auxiliary Building Zone A-14, Column F.8/H.2 and 18.1.
The above requirements are now included in Appendix R to 10 CFR Part 50 which became effective on We, therefore, expect that the licensee will conform to these requirements.
Subject to conformance to these requirements, these items are satisfactorily resolved.
3.3 Smoke Detection System Tests (3.2.2)
Our SER noted that in-situ tests aculd be conducted with a suitable smoke generating device to verify that a fire would be promptly detected by installed smoke detectors Ir.d that ventilation air flow patterns in the area do not signi#icantij reduce or prevent detection response.
Bencn tests would ce concucteo to verify that smoke detectors would provide prorp response and have adequate sensitivity to the products of combustion for the combustibles in the area where smoke detectors are installed.
If any fire detection systems are found to be inadequate, appropriate modifications will be made to provide adequate performance.
By letter dated July 31, 1979, the licensee indicated that various concepts had been reviewed and that use of a technique developed by NUTECH Cor? oration for siting of fire detectors showed some merit. The licensee evaluated N'JTECH's technique in a demonstration test held at the Yankee Nuclear Power Plant on August 23 and 24, 1979. The licensee concluded that although NUTECH's concepts have advanced the state-of-the-art, more testing or qualification would be necessary to provide assurance of acceptability.
The staff has also evaluated the NUTECH tests and has concluded that the method does not satisfy the staff requirement; the test requirement is beyond present state-of-the-art technology.
In addition, the NUTECH test report contains major deficiencies which detract from the credibility of the test method, such as inconsistencies in the interpretation and presentation of data, the use of unexplained rationale which require additional in-plant testing to improve the derived test results.
l'
. The licensee should, therefore, be relieved of zny schedule or commitment with this requirement until acceg2nce criteria can be developed that can be applied with the present day technology.
However, the licensee has not provided any infmmation on the requirement to conduct bench tests of smoke detectors for verification of prompt response and sensitivity to products of combustion in the area where installed. Thenefore, we will require that this be done to comply with the requirenents of our previously issued SER.
3.4 _ Cable Fire Barrier Penetrations Test Data (3.2.4)
Our SER noted that test date will be provided to demonstrate the adequacy of electrical cable fire barrier penetrations.
By letters dated July 31, and October 9,1979, the licensee orovided information on the cable fire barrier :enetrations.
The data contained in the letter of July 31,19I9, indicates that the penetrations are sealed with :. Corning Q3-6548 medium density Silicone RTV Foan The ir.staller certifies the materials used to the ASTM-E-119 Fire Endura 1ce Test and indicates that they have been installed as three hour fire seals with some exceptions.
The exceptions mentioned have been sealed with a minimum of 6 inches of silicone foam plus 1 inch of dammig, which in most cases is the thicknees of the penetrated structure.
We have reviewed the fire load characteristics for the Cable Vault and Control Room. This review indicates that the maximum hourly fire severity is far less that the rating of the fire barrier seals which are provided.
We find that the certifications provided demonstrate the adequacy of the cable fire barrier penetrations except that they do not show that a pressure differential across the seal (with the higher pressure on the exposed side) that is equivalent to the maximum pressure differential a fire barrier is expected to experience has no effect an the per-formance of the penetration seal. Subject to such a demon-stration we find these seals acceptable.
bx, ;d O L 'f r. Q~
jl '
ldF 3.5 Reactor Coolant Pump Lube Oil Fire Hazard (3.2.5)
Our SER noted that the licensee is evaluating a method of oil collection or routing to prevent the spread of oil or the use of alternative types of lubrican:s to reduce the fire hazards associated with the reactor coolant pump lube oil systems.
By letter dated July 31, 1979, the licensee provided infoma-tion on the evaluation conducted as a result of our concern.
The licensee proposed the implementation of a drip pan collection system to collect oil from all exterior leakage points and route it to a storage tank located at the base of the reactor coolant pump supports.
The licensee provided a description and sketch of the system.
We have reviewed the licensee's submittal and have talked by telephone with the licensee. The licensee's submittals do not confom with the staff's -epuirements.
The staff will require the following:
The Reactor Coolant Punp lubrica-i:r sptem snall te protected by either an oil collection syste, or ir autora-ic fire suppression system.
Oil collection systems shall be :a:aole of collecting lube oil from all potential pressurized and unpressurized leakage sites in the reactor coolant puns' lube oil systems and drain the oil to a vented closed container.
Requirements for a flame arrestor in the vent shall be detemined on the basis of flash point characteristics of the oil involved.
Leakage points to be protected snall include lift pump and piping, overflow lines, lube oil cooler, oil fill and drain lines and plugs, flanged connecticns on oil lires and lube oil reservoirs where such featuras exist on the reactor coolant pumps.
Leakage shall be collec ed and drained to a closed container that can P:ld the entire lube oil system inventory.
The drain lire shall be large enough to accommodate the largest poter-ial cil leak.
To provide adequate protection fa an SSE, one of the following should be provided:
a.
The lube oil system componer.ts whose failures could result in leakage should be designed to withstand an SSE without leakage; and, the dropping of oil collection system components during an SSE should not cause loss of operability of safety-related equipment; or
( b.
The oil collection system should be designed to with-stand an SSE and continue to be able to collect and drain leakage that may occur during an SSE.
In this case, the oil collection syste. should be adequate to collect oil from any external lube oil piping not designed te withstand an SSE, in addition to leakage from points identified above.
If an automatic fire suppression system is selected, either the automatic and manual fire suppression system or the lube oil system components whose failure could result in leakage should be designed to withstand the SSE.
All of the above requirements are now included in Appendix R to 10 CFR Part 50 which became effective on We, therefore, expect that the licensee will confom to these requirements. Subject to confomance to these requirements, these items are satisfactorily resolved.