ML20127B432
| ML20127B432 | |
| Person / Time | |
|---|---|
| Issue date: | 02/16/1984 |
| From: | Curtis R NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| To: | Benaroya V Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20127B435 | List: |
| References | |
| FOIA-84-577 NUDOCS 8404050416 | |
| Download: ML20127B432 (2) | |
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MEMORANDUM FOR: Victor Senaroya, Chief Chemical Engineering Branch, NRR Walter Butler, Chief Containment Systems Branch, NRR Karl Kniel, Chief -
Generic Issues Branch, NRR
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Vincent Noonan, Chief -
Equipment Qualification Branch FROM: Robert T. Curtis, Chief Containment Systems Research Branch, RES
SUBJECT:
" CABLE RESPONSE DURING THE HYDROGEN BURN-DEMONSTRATION
. TEST AT THE NEVADA TEST SITE" As you are aware, the hydrogen combustion demonstration program at the Nevada Test Site was recently completed. During the second phase of this test program safety related equipment was exposed to the hydrogen burn environment. The objective of these experiments was to assess the survivability of equipment i
under conditions outlined in the final hydrogen rule. A key objective was to provide a data base for closure on the issue of survivability of equipment in a large dry containment. The purpose of this memorandum is to provide you with some preliminary observations on the response of a specific type of equipment (cables) during these tests.
In my memorandum of January 19, 1984, I outlined three final tests to be conducted at NTS. The tests have been completed and the preliminary results from the program will be made available to you as soon as it becomes available.
Upon the completion of the program, John Larkins visited the facility to j
preview the results of the final tests and to make plans for a final report.
I '. During the visit he made certain observations which we feel are worthwhile to l
bring to your attention. In viewing the videocassette recordings of these experiments it was noted that at relatively high hydrogen concentrations, i representative of approximately 755 metal-water reaction, f*135H with 305 l :
steam and 135 H, with sprays and fans) the cables burned extensive,y, T both
! i , during the hydrbgen gas burn and afterwards. Post test examination revealed extensive charring, pitting, cracking and holes where a metallic surface was l
L l, clearly visible. The first conclusion was that the metallic surfaces were l
- exposed conductor, however, after later discussions with EPRI it was concluded that the surface was probably metallic braids or metallic paper.
EMCLOSURE 3 J
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A team from EPRI ' utility representatives. Westinghouse and SA'NDIA visited the site on February 7 & 8, 1984 and visually ins;,ected most of the equipment used A brief trip report from SANDIA is enclosed. The in the various tests.
consensus from this team was that in none of the cable samples was metal The actual testing of the cable conductor and insulator conductor visible.
will be done over the next six weeks or so and at that time we will be as to the functional capabilities of the conductor and insulation. EPRI will informed
- 17. 1984. Also a provide a qualitative quick-look report on or about FebruaryIf you desire more -
VCR tape is available of these last series of experiments.
information on the observation from these tests or viewing of the VCR tape, please call me or John Larkins (X74478).
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Robert T. Curtis, Chief Containment Systems Research Branch
Enclosure:
As stated .
cc: R. Minogue. RES D. Ross, RES
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r Date: February 10,1984 ,
To: John Larkins, NRC From: W. H. McCulloch, 6445 On February 6-7,1984 Bill McCulloch, John Aragon, and Don King of SLA visited the NTS Hydrogen Burn Facility to inspect the condition of equipment and cable / splice samples after a series of hydrogen burn tests' conducted by EPRI.
Also present for the inspection were Jack Haugh and George Sliter of EPRI.
Dick Miller of Westinghouse, Don Randall of Astron, and John Wanless of the NUS
- Corporation The calorimeters we had supplied were of special interest to use, but, at the request of John Larkins, NRC, we also inspected the other equipment and cable / splice samples from their original (new) condition, and we made no attempt to evaluate or interpret the observed conditions of the samples or to assess their operability or reliability. The equipment and samples were tagged and photographed and the condition of each item was noted in an Engineering
, Record book. The inspection consisted of visually examining the exterior of the equipment and cable / splice samples and the interior of the equipment as their covers were rennved. At times unusual or unexpected " flakes", " crusts" or corrosion were refu n d from the equipment and placed in sample bags.
The equipment inspected included absolute and differential pressure gages, solenoid valves, limit switches, resistive temperature devices, penetration assemblies, a fan rotor, and a motor operated valve. Cable samples were obtained from various manufactures: Kerite, Rockbestos, Samuel Moore, Raychem.
Okonite, Boston Insulated Wire & Cable and Anaconda. Most of the cable samples I
had been spliced inte loops using a variety of splicing techniques not all of j the type used in nuclear facilities. We are to be informed later by EPRI which l were the higher grade splices.
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! In general, the equipment exteriors were scratched, discolored and corroded.
l evidence of their handling and exposure to fires and high temperatures. There were not however, any indications of external damage to the equipment. Upon removing the covers we found water condensed on most surfaces inside the pressure gages. The most probable source for this water intrusion is through the feed throughs for the experimental instrumentation (which is not typical of installation in nuclear facilities). But there was no way to assure that the
" nuclear grade" gaskets and seals did not allow the intrusion of at least some l of the water. (It should be noted that " nuclear grade" installation procedures O
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John Larkins and checks must'be meticulously followed: other techniques' judged acceptable even by experienced and careful installers, can lead to problems as occured repeatedlyinthistestseries.) Except for the condensation and small amounts for foreign material (scale from evaporated water and bits of construction material, e.g., metal filingss) we found no evidence of damage or malfunction.
The presence of the water might give some concern There if the wascomponent were enough water present to
- expected to perform over an extended period.
cause shorting in a printed circuit board if the potting material were absent -
or compromised.
Damage t'o the cable / splice samples ranged from virtually none to severe damage to the cable jacket. Except for some splices which may not have been " nuclear grade" our visual inspection revealed no evidence of failure of the conductors or insulators. However, there was in many cases sufficient damage to the cable outer jacket to seriously doubt its ability to protect the inner cable parts from a wet environment. For instances, if the inner insulation shrank back slightly from the splices, moisture could easily cause shorts. In the absence of defined criteria for survivability, we cannot say that we observed success Of approximately fifty cable samples, only two were virtually free or failure. Several of damage. showed slight surface melting and a few were charred without significant surface wrinkling or bulging. On many samples the jacket had expanded (either from its own phase change or from pressure generated by high temperture.
gases inside the jacket) and collapsed giving a heavily wrinkled or knurled appearance (like the rough bark on a mature tree). In the more severe cases 6 the jackets had holes and/or splits to reveal the inner layers. All but one of the splices showed some damage (usually substantial shrinkage or splitting of the splice jacket). Again, our observations were limited primarily to the cable jacket and we saw no clear indication of damage to internal parts or of a cable's inability to perforin its function.
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