ML20202G606
| ML20202G606 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 03/21/1986 |
| From: | Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| To: | Kirsch D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| REF-PT21-86, REF-PT21-86-123-000 ANPP-35637-EEVB, DER-86-03, DER-86-3, PT21-86-123, PT21-86-123-000, NUDOCS 8604140444 | |
| Download: ML20202G606 (5) | |
Text
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h ts Arizona Nuclear Power Project
#g df P.O. BOX 52034
- PHOENIX ARIZONA 85072-2034 March 21, 1986 Nh
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ANPP-35637-EEVBJr/LAS /D1 dL9,2.11 U. S. Nuclear Regulatory Commission Region V 1450 Maria Lane - Suite 210 Walnut Creek, California 94596-5368 i
Attention:
Mr. D. F. Kirsch, Acting Director Division of Reactor Safety and Projects Palo Verde Nuclear Generating Station (PVNGS)
Units 1, 2, 3 Dockets Nos. 50-528, 529, 530 i
Subject:
Final Report - DER 86-03 A 50.55(e) and 10CFR21 Condition Relating to Lack of Fire Barriers in Seismic Gap Areas File: 86-006-216; 86-056-026; D.4.33.2
Reference:
(A) Telephone Conversation between R. C. Sorenson and D. R. Larkin on January 24, 1986 (Initial Reportability - DER 86-03)
(B) ANPP-35278, Dated February 24, 1986 (Interim Report - DER 86-03) l
Dear Sir:
Attached, is our final written report of the Subject Deficiency which has been determined to be Not Reportable under 10CFR50.55(e) and 10CFR21.
l Very truly yours, Ettlu & n/d,,y
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E. E. Van Brunt, Jr.
Executive Vice President Project Director EEVBJr/DRL/ldf Attachment (s) cc: See Page 2 8604140444 860321 PDR ADOCK 05000528 l l S
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e ANPP-35637-EEVBJr/LAS/D'RL-92.11' March 21. 1986
. DER 86 FINAL REPORT
'Mr. D. F. Kirsch 1 Acting Director 4-Page 2 cc:
J. M. Taylor, Director Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission Washington, D. C.
20555 A. C. Gehr (4141)
R. P. Zimmerman (6241)
Records Center Institute of Nuclear Power Operations 1100 Circle 75 Parkway'- Suite 1500 Atlanta, Georgia 30339 4
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FINAL REPORT - DER 86-03 DEFICIENCY EVALUATION 50.55(e)
ARIZONA NUCLEAR POWER PROJECT (ANPP)
PVNGS 1, 2, 3 I.
Description of Deficiency The PVNGS Fire Hazards Analysis (FHA) did not identify the 6-inch seismic gap area between the Diesel Generator and Control Buildings (100' and 120' elevations). Trains A and B safe-shutdown cables associated with the diesel generators, are routed in this gap through conduit expansion / deflection fit-tings and open cable trays which were not provided with vertical fire-rated barrier separation. Since there is no fire detection and suppression equip-ment within the gap area, the safe-shutdown circuits for the diesel genera-tors did not comply with Appendix R,Section III.G.2 requirements.
EVALUATION All seismic spaces between plant structures were evaluated for potential fire hazard. A total of nine (9) seismic gap spaces were identified. Four of the nine seismic gap apaccc were not previously evaluated in the FHA.
Only two of which were found to contain redundant safety related circuits without vertical fire-rated barrier separation.
One gap is between the Diesel Genera-tor and Control Buildings, and the other gap is between the Auxiliary Building and Condensate Storage Tunnel. However, the lack of separation found in the Auxiliary Building and Condensate Storage Tunnel seismic space is an extension of the physical layout existing in the tunnel itself and is therefore addressed by an existing deviation to 10CFR50, Appendix R, presented in the FdA (see FSAR i
Section 9B.2.9).
The only area of concern is the seismic gap between the Diesel Generator and Control Buildings, at the 100' and 120' elevations.
j An evaluation of the seismic gap between the Diesel Generator and Control Build-ings was performed to assess the possibility of a fire effecting the safety re-lated circuits. The existing arrangement of circuits and other physical aspects i
of the seismic gap is considered an acceptable deviation from Appendix R,Section III.G.2 for the following technical reasons:
(a) The area (6-inches wide) is not accessible and cannot be used for storage of combustibles. The only probable entry points for stored combustibles are two doorway openings in each gap area.
(b) The external openings of the space at the outside walls of the buildings are provided with metal expansion joint closures, and the top is enclosed by a neoprene e7pansion joint.
(c) Both the Diesel Generator and Control Building walls are heavy concrete construction 3-hour-rated fire walls.
l (d) There are no above-ground flammable liquid storage tanks which could rupture and allew flammable fluid to enter the space from the outside.
l (e) Flammable liquids inside the Diesel Generator Building will not enter the space because of curbs and sumps.
(f) No piping containing flammable liquids or gases are in the space.
1 Final Report - DER 86-03 Page 2 (g) The distance between the nearest Train "A" circuit and Train "B" circuit (both of which are normally deenergized and en-closed inside flexible neoprene boot material) is approxi-mately 10 feet, 9 inches.
(h) The closest dimension between Train "A" and Train "B" cable in_ exposed ccble tray is approximately 21 feet, with normally energized 125 V-dc cables. All circuits are verified to have-proper fuse / breaker circuit protection to protect against auto ignition of the cables due to overcurrent conditions.
(i) The amount of fixed combustible load within the gap.is minimal, consisting of the neoprene material from the conduit fitting boots / roof seal and approximately 6 pounds of cables (3 pounds for each Train and 1 pounds in each of four trays). The cables meet the requirements of IEEE 383 and meet additional criteria of resisting 210,000 BTU / hour of heat.
(j) The design, as noted in (g) and (h) above, meets Regulatory Guide 1.75
" Physical Independence of Electric Systems".
(k) There are no potential ignition sources in the space.
Based upon the above, a fire in the seismic gap space large enough to cause a loss of both Diesel Generators is remote and highly unlikely-to occur. A fire of such magnitude will require the admission of-large amounts of transient combustibles and an ignition source into the gap area through the doorway openings. Existing administrative control procedures and continuous reviews of the units for transient i
combustibles by the utility fire protection staff will prevent this type of fire.
The root cause of this condition was that during the performance of the Fire Hazard Analysis, this enclosed seismic gap area for each-unit was not identified on the drawings and, thereby, not evaluated.
This inadvertent omission of the seismic gap between the Diesel Generator and Control Buildings' (100' and 120' elevations) from the original evaluation is an isolated occurrence. The evaluation of all other seismic gaps, of each unit, revealed that they comply with Appendix R commitments.
II.
Analysis of-Safety Implications Based on the above,_the potential for a fire in'this seismic. gap area-is not credible due to the inaccessibility of the areas to transient combustibles and the absence of credible ignition sources. This condition, if left uncorrected, would.not represent a significant safety condition and is, therefore, evaluated as not reportable under 10CFR50.55(e) and 10CFR21.
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Final Report - DER 86-03 Page 3 III. Corrective Action Each doorway opening to the seismic gap area, between the Diesel Generator and Control Buildings (100' and 120' elevations), will have 1-hour fire rated scismic gap seals installed to provide addi-tional assu.ance against exposure hazards associated with transient combustibles. DCP 20A/30A-ZY-179 has been initiated to add the-1-hour fire rated seismic gap seal to the gap areas of Units 2 and 3; the Unit 1 seal was ins *alled per PCR 86-13-ZY-001 and CWO 129075.
This DCP is forecasc to be released by March 28, 1986. As an interim corrective action, a continuous fire watch was' established at'the seismic gap in Unit I by ANPP and remained in place until the final seismic gap seal was installed..In accordance with LER 1-85-096, a continuous fire watch was established in Unit 2 by ANPP and will remain in place until the seismic gap seal is installed. If necessary, a fire watch will be established for~ Unit-3.if installation'of the gap seal is not completed prior to fuel load. FSAR Change Notice #2125 modifies FSAR Appendix 9B.2
" Fire Hazard Analysis" to reflect the review of the seismic gap area between the Diesel Generator and Control Buildings.
Reference 1.
EER 85-ZG-003, December 8, 1985 l
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