ML20214N773
| ML20214N773 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood, 05000000 |
| Issue date: | 09/10/1986 |
| From: | Miosi A COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| 2083K, IEIN-84-90, NUDOCS 8609170025 | |
| Download: ML20214N773 (23) | |
Text
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ____________ _ ______
COnunonweehh h d7 CPe First Nebonel Plaza, Chece00, lHinois '
s Address Hoply to: Post Omco Box 767 Checago,lHinois60000 0767 September 10, 1986 Mr. Harold R. Denton U.S. Nuclear Regulatory Commission Office of Nuclear Reactor-Regulatory Washington, DC. 20555
Subject:
Byron Station Units 1 & 2 Braidwood. Station Unit 1 & 2 Supplemental Information on
~ Environmental Effects of Main Steam Line Break Outside Containment Information Notice 84-90 NRC Docket Nos. 50-454. 455. 456. and 457 I
~
Reference (a):
July 22, 1986 A.D. Miosi letter to H.R. Denton
Dear Mr. Denton:
Enclosed is information requested as discussed during a
-conference call with members of your staff on August 20, 1986, which provides further clarifications to our Reference (a) submittal on the issue of environmental effects of a main steam line break outside containment.
Enclosed is a. description of the computer model utilized for the steam tunnel and valve room temperature calculations, a diagram of the model, and the'RELAP 4 Mod 6 input listing of the model.
The computer code utilized in the WCAP 10961 "Steamline Break Mass / Energy Releases for Equipment Environmental Qualification Outside Containment" was the LOFTRAN code which is. documented in l
Supplement 1.to WCAP 8822 " Mass and Energy Releases Following a l~
Steam Line Rupture".
The mass / energy release data actually employed in.the Byron and Braidwood calculations was taken from WCAP 10961 for a " Category 1" plant.
All applicable casea were run and used to determine the limiting cases documented in the previous submittal.
The specific tables used were Tables A-1.1 to A-1.30 as well as Tables A-1.31, A-1.32, A-1.35, A-1.36, A-1.39, A-1.40,'A-1.43, A-1.44 A-1.47, and A-1.48.
The latter tables covered the sensitivity of the blowdown to ranges of AFW flow bounding the Byron and Braidwood plants.
8609170025 860910 PDR ADOCK 050004S4 P
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. Also enclosed are clarifications which specifically address questions on the approach and bases utilized in the extension of qualification to higher temperatures than the components were tested to, and the effects of higher temperatures after closure of the Main-Steam Isolation Valve (MSIV).
Included with these clarifications is the thermal lag analysis of the MSIV components.
Based on the enclosed review of the qualification data and the failure modes review of the affected components in addition to the Reference (a) submittal, we conclude that the postulated superheated steam transient will not adversely affect safety related equipment in the steam tunnel.
Should you have any questions concerning this matter please contact-this office.
One signed original and fifteen copies of this letter and enclosures are provided for your review.
Very truly yours, k
A. D. Miosi Nuclear Licensing Administrator
/klj cc:
J.
Stevens L. Olshan 2083K
MODEL DESCRIPTION The main steamline break is assumed to be in the unit I section of the second quadrant valve room.
The RELAP4/ MOD 6 computer code is used to determine the temperature transient. This analysis assumes a homogeneous mixing of steam and air throughout the subcompart-ments and do not account for the heat sinks. The enti re model con-sists of 8 volumes and 8 junctions as shown in Figure 1.
The volume descriptions are summarized as follows Volume 1 : Atmosphere (TDV)
Volume 2 : Second quadrant valve room - break location.
Volume 3 : Main steam tunnel second quadrant Volume 4 : Main steam tunnel Volume 5 : Main steam tunnel - first quadrant Volume 6 : First quadrant valve room.
Volume 7 : Main steam tunnel - first quadrant Volume 8 : Main steam tunnel - first quadrant The basic assumptions and information used in the analysis are sum-marized as follows :
- 1. Initial subcompartment conditions of 14.7 psia, 90 F.
and 30 % relative humidity are assumed.
- 2. Only one break occurred per analysis.
- 3. The mass and energy release rates for the postulated main steamline break is taken from Reference 6.(wcAp ioggs)
- 4. No heat transfer out of the rooms is considered.
- 5. The HVAC systems are not considered.
- 6. The transient duration of 1800 seconds is assumed.
- 7. No automatic or manual break isolation is modeled.
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FIGURE 1
s BYRON STEAM TUNNEL MODEL MDUCMMdMM3%MZMMMMHCH2HMu%MMMUNH UZHMMMMMMMMZMMMMMMMMMUMMMZMMMMMMMMMMMM M
8 VOLUMES / 8 JUNCTIONS MODEL M
M V1 : ATMOSPHERE (TDV)
M M
V2 : VALVE ROOM - 2ND QUADRANT M
M V3 : MAIN STEAM TUNNEL - 2ND QUADRANT M
M V4 : MAIN STEAM TUNNEL M
M V5 : MAIN STEAM TUNNEL - IST QUADRANT M
M V6 : VALVE ROOM - IST QUARDRANT M
M V7 : MAIN STEAM TUNNEL - IST QUADRANT M
M V8 : MAIN STEAM TUNNEL - IST QUADRANT M
M---------
FILE BYRON.CNTL(STY) ----- 11/01/85 M
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM M------
PROBLEM DIMENSIONS DATA CARD --------
M LDMP NEDI NTC NTRP NVOL NBUB NTDV NJUN NPMPC NCKV NLK 010001
-2
-7 3
2 8
0 1
8 0
0 0
+
1 0
0 0
0 0
3 M
'NFILL NSLB NGOM NMAT NCOR NHTX ISPROG 010002 0.0 1.0 MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM M
. MINOR EDIT VARIABLE DATA 020000-AT 2 AT 3 AT 4 AT 5 AT 6 A7 7 AT 8 MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM M
TIME STEP DATA CARDS M
NMIN NMAJ NDMP NCHK DELTMAC DELTMIN LAST ENDCPU 030010 100 10 100 0
0.01 1.0E-6 300.0 MSTARTUP 030020 50 10 100 0
0.02 1.0E-6 1000.0 MTRANSIENT 030030 25 10 100 0
0.04 1.0E-6 10000.0 MTRANSIENT MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM M
TRIP CONTROL CARDS M
IDTRIP IDSIG IX1 IX2 SETPT DELAY 040010 1
1 0
0 1800.0 0.0 M END PROBLEM 040020 2
1 0
0 0.1 0.0 M START FILL FLOW MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM M-----
VOLUME DATA PART 1 M
IBUB IREAD P
TEMP X
V 050011 0
1 14.7 90.0 0.3 1.E10 MATMOS 050021 0
0 14.7 90.0 0.3 21805.4 MVALV RM-2NDQ 050031 0
0 14.7 90.0 0.3
'13695.0 M2ND QDRT 050041 0
0-14.7 90.0 0.3 34865.0 MMAIN TUNN 050051 0
0 14.7 90.0 0.3 35016.0 MIST QDRT 050061 0
0 14.7 90.0 0.3 21805.4 MVALV RM-ISTQ 050071 0
0 14.7 90.0 0.3 17388.4 MIST QDRT 050081
'O O
14.7 90.0 0.3 13529.9 MIST GDRT M----
VOLUME DATA PART 2 --------------------
M ZVOL ZM JTPMV FLOHA DIAMV ELEV IAMBLO 050012 1.E3 0.0 0
1.E7 0.0 0.0 0
050022 36.33 0.0 0
742.95 0.0 0.0 0
050032 19.0 0.0 0
317.0 0.0 0.0 0
050042 19.0 0.0 0
203.0 0.0 0.0 0
050052 20.0 0.0 0
432.0 0.0 0.0 0
050062 36.33 0.0 0
742.95 0.0 0.0 0
050072 29.0 0.0 0
432.0 0.0 0.0 0
050082 19.0 0.0 0
280.0 0.0 0.0 0
MMMMMMMMMMMMMMhMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM M
TIME DEPENDENT VOL INFO M
IRIN TIM PTABL TEMP XTABL ZTABL 070101 1
1.E6 14.7 90.
0.3 0.0 MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMhMMMMMMMMMMMMMMMMMMMMMA M
JUNCTION DATA M
IH1 IH2 IP IV HP AJUN ZJUN INERTA FJUNF FJUNR 080011 2 3 0 0
- 0. 0 -
146.0 0.0
.0 1.5685 1.5685 080021 3 4 0 0 0.0 199.8 0.0
.0 2.1860 2.1860 080031 4 5 0 0 0.0 199.8 0.0
.0 2.7530 2.7530 080041 5 6 0 0 0.0 146.0 0.0
.0 1.5685 1.5685 080051 5 7 0 0 0.0 373.6 0.0
.0 2.2600 2.2600 080061 7 8 0 0 0.0 270.8 0.0
.0 2.2600 2.2600 080071 8 1 0 0 0.0 270.8 0.0
.0 1.0656 5000.
080081 0 2 1 0 0.0 1.0 0.0
.0 0.0000 0.0000 M----
JUNCTION DATA --- PART 2 -------------------
M JVERTL JCHOKE JCALCI MVMIX DIAMJ CONCO ICHOK IHQ SRCOS IADJ 080012 1
-1 2
3 0.0 1.0 0
0 0.
0 080022 1
-1 2
3 0.0 1.0 0
0 0.
0 080032 1
-1 2
3 0.0 1.0 0
0 0.
0 080042 1
-1 2
3 0.0 1.0 0
0 0.
0 080052 1
-1 2
3 0.0 1.0 0
0 0.
0 080062 1
-1 2
3 0.0 1.0 0
0 0.
0 080072 1
-1 2
3 0.0 1.0 0
0 0.
0 080082 1
3 2
3 0.0 1.0 0
0 0.
O MMMMM FILL DATA MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
e ENVIRONMENTAL EFFECTS OF MAIN STEAM LINE BREAK OUTSIDE CONTAINMENT Clarification of Approach and Methods
==
Introduction:==
As explained in'a previous submittal (Commonwealth Edison letter, A. Miosi to H. Denton, " Evaluation of Environmental Effects of Main Steam Line Break Outside Containment", July 22,1986), superheated steam release from a Main Steam Line Break (MSLB) could, given a set of low-probability circumstances, result in exceeding the existing design basis Environmental Qualification temperatures in the Main Steam Tunnel.
The effects of these higher temperatures were addressed in the previous submittal.
Clarifications to that submittal are contained in this document.
Specifically addressed are questions on the approach and bases utilized in the extension of qualification to higher temperatures than the components were tested to and the effects of high temperatures after closure of the Main Steam Isolation Valve (MSIV).
The extension of qualification is addressed first and the requirements for post valve closure is addressed second.
Extension of Oualification:
The extension of the qualification was achieved in accordance with 10CFR50.49 which states:
"Each item of-electric equipment important to safety must be qualified by one of the following methods:
(1)
Testing an identical item of equipment under identical conditions or under similar conditions with a supporting analysis to show that the equipment to be qualified is acceptable.
(2)
Testing a similar item of equipment with a supporting analysis to show that the equipment to be qualified is acceptable.
(3)
Experience with identical or similar equipment under l
similar conditions with a supporting analysis to shov that
~
the equipment to be qualified is acceptable.
(4)
Analysis in combination with partial type test data that supports the analytical' assumptions and conclusions."
The qualified components in the Main Steam Tunnel were tested to environmental parameters which met or exceeded the Byron /Braidwood Environmental Qualification requirements for the area which was a transient which peaked at 328cF.
In general, the approach taken to extend the qualification was to review qualification reports (for those components which must remain functional after a MSLB) and assess the margin over the original requirements.
The steam line pressure transmitters are qualified by test to 420oF which exceeds the predicted maximum of 399oF prior to MSIV closure.
As a result no re-evaluation was required to extend the qualification to the time of MSIV closure.
Similarly, cables and splice kits used in this area were tested to transients more severe than the worst predicted tr'ansient up to the time of MSIV closure, with one exception.
Brand ~ Rex cables were tested to 385oF, 14o below the predicted temperature at the time of MSIV closure.
Because the cable insulation is a thermosetting
-compound and will not see sudden deterioration until ignition temperatures are reached, the approximately 1 minute that the tested i
temperature is exceeded will not adversely affect the functionality of the cables.
For the MSIV, which was tested to the plant unique parameters, no other qualification data exists for the entire actuator and ratesting is not practical.
However, the actuator is made up of mechanical components which are not affected by temperature and electrical assemblies which are functional components themselves and have been tested to more severe parameters for other applications.
The materials used in the components have been reviewed.to provide additional assurance of the operability of the components and to confirm the applicability of the test results.
The safety related (fast acting isolation) portions of.the MSIV actuator consist of pneumatic and hydraulic reservoirs, actuation cylinder and piston, limit switches, air operated actuation valves, and solenoid operated pilot valves.,
The only electrical components are the limit switches and the solenoid valves.
The only non-metallic portions of the mechanical / hydraulic parts of.the actuator are elastomers used as seals.
The only seal which is in an application which would be considered active'are-the Ethylene-Propylene Rubber (EPR) seals on the actuator piston.
These seals are rated for service temperatures of up to 400cF with continuous service at 300oF and were tested as part of the actuator to the plant specific transient which pc.aked at 328oF.
A thermal lag analysis, described in the previous submittal, established that the EPR temperature will not exceed 270oF
. prior'to valve closure.
A more detailed description of the thermal lag analysis is included in Attachment A, " Thermal Lag Analyses of
)~
MSIV Components."
As a result, the mechanical / hydraulic portions of j
the actuator are considered qualified until after MSIV isolation.
1 The Namco limit switch'used on the HSIV has been tested to a peak temperature of 391oF with 340oF for 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.
A conservative thermal lag analysis using the calculated superheat transient until the time of valve closure demonstrates that the non-metallic portions i
of the limit switch will remain below 340oF during the transient.
This establishes that the existing qualification test is bounding and the limit switch is qualified.
The solenoid valves used to actuate the MSIV were also tested as part of the MSIV actuator.
Additional test information is available for similar solenoids using identical materials.
These components were tested to 4200F without failure.
Evaluation of the components resulted in the conclusion that qualification can be extended to the components installed under option 2 of 10 CFR 50.49.
Post Isolation Oualification:
After the HSLB which is postulated to cause the superheat conditions and temperatures up to.399oF at the time of isolation, continued blowdown from a crack in the break exclusion zone or as the result of.a failed MSIV will continue to increase the environmental temperature.
The maximum temperature which could occur in the Steam Tunnel is dependent upon the size ~of the Main Steam Line break and the response of the Reactor Coolant (RC) System.
Highest temperatures (about 563nF) would occur following large breaks and rapidly decrease due to overcooling of the~RC System.
The most severe case for-equipment qualification would be a smaller break which peaks at a later time and lower temperature but has a longer duration at high temperature.
Transients which have been cal.culated indicate a worst case of temperatures of.approximately 400or at 30 minutes after the break.
This temperature continues to increase until cooling of the RC
~
System results in decreasing steam temperatures.
Since the RC System will initially be cooled very rapidly and then be~ cooled at a rate of 50"F per hour, a worst case assumption is made that the blowdown peaks at about 500nF and decreases at 50oF per hour until approximately 350or is reached (corresponding to 400 psi where the RHR can be initiated and steam generator heat removal is no longer needed).
In order to evaluate the effects of this transient on the function of the MSIV's, the design was reviewed to determine which
{
components are required to maintain-the valve closed, and which components have a failure mode which could potentially result in re-opening of the MSIV.
After the HSIV has closed, the pressure transmitters have no required. function or adverse failure mode.
The pressure signal is used to initiate valve closure but has no part of'the valve opening function.
All possible pressure transmitter failures will leave the valve in its existing position.
The cables and splices used in this area are not susceptible to failure as a result of the limited time at elevated temperatures postulated here.
If a cable did fail, the most likely failure is a short to ground which would result in loss of. power in that circuit.
As discussed below, the MSIV is not dependent upon power to remain
~
closed against pressure.
Therefore, the only possible failure which would result in re-opening of the HSIV is a hot short from one cable-to another specific cable without grounding such that the HSIV opening signal is simulated.
Since the valve cicsure signal overrides the opening signal, and the cable / splice failure mode of loss of insulation at 500oF or less for a limited time is not considered credible, this possibility is dismissed and the cables / splices are considered qualified for post isolation service also.
After the HSIV closes, differential pressure across the valve disc will hold the MSIV in the closed position.
This feature is part of
'the design of'the MSIV and is intended to eliminate reliance on electrical or control systems to maintain isolation.
This mechanical means of keeping the HSIV closed is also independent of the hydraulic
closing system of the actuator.
The only potential for re-opening of the HSIV is if the actuator receives or, through failure, generates an opening signal.
This erroneous opening signal would have to be combined with a failure that causes loss of the closure signal since the closure signal overrides the opening signal.
Because the pressure transmitters and other components in the Tunnel are not potential sources of a spurious opening signal,the potential for opening due to environmental effects on the solenoid valves and limit switches are reviewed here.
The solenoid valves have two potential failure modes open circuits and short circuits in the solenoid coils.
One solenoid is I
energized after valve closure in each closing circuit.
Because of the mechanical design of the valve discussed above, this solenoid is not required to maintain the HSIV in the closed position.
The design includes this energized solenoid to facilitate testing and startup because the valve will potentially drift with no differential pressure across the disc.
Open and short circuits were postulated for all the solenoids in the design and none were found to result in re-opening of the closed valve.
The limit switches serve to help control the valve by sensing the extent of the actuator travel and to provide indication of the valve position.
The limit switches are NAMCO Hodel 180 switches.
These switches connect sets of contacts based on the mechanical position of a lever.
The limit switches were reviewed to determine if any combination of connections and positions would cause the valve to re-open.
The only limit switch with this potential is a limit switch which " seals-in" the opening circuit to prevent drifting.
When the valve partially re-opens, this limit switch activates the opening circuit and moves the valve to the full open position.
Again, the closing signal overrides this signal.
Re-opening of the valve would l
require failure of the closing circuit, and movement of the valve or internal failure of the limit switch which would close previously open contacts.
Examination of the switch demonstrates that this failure will not occur since it would require a spurious mechanical motion of l
a metal component or a gross deformation of the insulating materials I
causing a hot short without a short to ground.
l The only spurious mechanical motion which could affect the limit switch is the movement of the HSIV and, because of the mechanical locking feature of the design discussed above, this movement is not credible.
The insulcting material is asbestes filled phenolic.
Appendix B contains excerpts from and references to relevant testing data.
The high temperature failure mcde of this material is darkening i
and internal crazing with associated loss of strength after prolonged l
exposure.
Intermittent exposures to temperatures of 500oF will not seriously affect physical properties. (Handbook of Common Polymers, 7
N.J. Roff and J.R. Scott, CRC Press, 1971.)
Irradiation inhibits long term effects of temperature by reducing oxidation but should have little effect on short term temperature related degradation.
Specimens have been exposed to temperatures as high as 900oF in radiation tests without complete failure. (Radiation Effects on Organic Materials in Nuclear Plants, EPRI Report NP-2129, 1981.)
Phenolic laminates exposed to SOOo for 1/2 hour without radiation retained flexural strength of about 47,000 psi.
Subsequent testing of nonirradiated and irradiated specimens at temperatures of 600, 700, 800,
and 900oF demonstrated retention of some strength. (Battelle Radiation Effects Information Center Report No. 21, 1961.)
Based on this information we conclude that there are no credible failure modes.
which would result in re-opening of the HSIV.
==
Conclusions:==
Based on the above review of the qualification data and the failure modes review of the affected components in addition to the previous submittal, we conclude that the postulated superheated steam transient will not adversely affect safety.related equipment in the steam tunnel.
A L
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Appendix A
Thermal Lag Analysis of MSIV Components a
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s Project Nos. 4391/92 4683/84 Thermal Lag Analyses of MSIV Components The thermal lag analyses of the internal's of the MSIV actuator hydraulic cylinder, the MSIV actuator pneumatic reservoir, and the NAMCO limit switch were performed using the Sargent & Lundy-propriety computer program KITTYlA.
KITTYlA is a general node /
~
path computer code used to calculate node properties and path heat flow rates for transients in user specified configurations.
The analyses examined the thermal response of the component surface and internals to several main steam line breaks.
The heat transfer mechanisms considered in the analyses to assess heat transfer to the surface of the components are consistent with'those identified in NUREG-0588 Appendix B.
Additionally, radiation heat transfer was considered in these analyses.
The mechanisms considered are therefore as follows:
a.
Forced convection heat transfer between the valve house environment and the exterior of the component, b.
Condensation heat' transfer on the exterior of the component, and c.
Radiation heat transfer between the valve house environment and the exterior of the component.
The results of the analyses indicate that forced convection and radiation are the predominant modes of heat trunster tc the surface of the ccmponents during the transient.
A.
Forced Convection The forced convection heat transfer was nodeled using the correlation applicable for heat transfer to flat plates as given in Kreith, " Principles of Heat Transfer", 3rd Edition, on page.341.
The free stream steam velocity used in the correlation was determined based on the steam blowdown Project.Nos. 4391/92 4683/84 Thermal Lag Analyses of MSIV Components (Cont'd)
A.
Forced Convection (Cont'd) rate, and orientation of the component within the room.
Since the components are located close to the MSIV which is located near a penetration, the velocity was determined by dividing the blowdown rate by the product of the steam / air density and penetration area.
This resulted in values for the forced convection heat transfer coefficients of approximately 2
6.0, 1.1, and 2.3 Btu /hr ft - F for the limit switch, hydraulic cylinder, and pneumatic reservoir, respectively.
Natural convection heat transfer was ignored since the effects of forced convection would be predominant throughout the blowdown.
B.
Condensation Condensation heat transfer was modeled using the correlation obtained from Kreith on page 527.
The values for the con-densation heat transfer coefficients ranged from 1000-3000 Btu /hr-ft - F.
Condensation heat transfer continued until the surface of the component reached the saturation tempera-ture corresponding to the pressure in the valve house.
The results indicate that condensation heat transfer ceases very early in the thermal lag transients.
C.
Radiation Radiation heat transfer between the valve house environment and the exterior of the components was modeled ucing relationships for radiation between a steam environment and a gray body given in Kreith, Section 5-8.
Conser-Vative assumptions were used to determine the emissivity of the steam and steel body in the analysis of the limit switch.
Emissivities of unity were assumed for the steam and steel surfaces in the analyses of the hydraulic cylinder and pneumatic reservoir.
Project Nos. 4391/92 4683/84 Thermal Lag Analyses of MSIV Components (Cont'd)
D.
Additional Conservative' Assumptions The initial temperature of the internals of the components was taken as 122*F which corresponds to the maximum' design normal operating temperature for the valve house.
For the analyses of the hydraulic cylinder and pneumatic reservoir surface temperatures of 212'F were assumed.
This corresponds to an infinite and instantaneous heat transfer rate due to condensation heat transfer being applied at the beginning of the transient analysis.
The boundaries of the components were treated as adiabatic with regard to any additional heat sink and as being exposed to-a free stream.
In reality, the components are attached to other steel members which act as heat sinks and partially shield the components of interest from the direct effects of the free stream.
The stream velocity used in the determination of the forced-convection heat transfer coefficient was determined based on the area of the room penetrations local to the components instead of to the rooms cross sectional area.
This area results in a higher velocity than using the cross section area of the room.
The higher velocity produces a higher forced convection heat transfer coefficient which was
~
employed in these analyses.
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L Appendix B
t Service Conditions and Testing Data j
1 i
for Asbestos Filled Phenolic l
(From Sargent & Lundy Qualification Data' Files)'
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Page 22 of 44 MATERI AL DATA AND SHEtr t eFE GUIDELINES AGING DATA PHYSICAL PROPERTIES PARAME TER VALUE RE F E RE NCE PARAME TE R VALUE RE F E RE NCE MAX. SERVICE TEMPERATURE ("F )
350-500 32 TENSILE STRENGTH (PSI) 4500-7500 32 CONT 1NUOUS EXPOSURE : 1000 HR$.
ACTIVATION ENERGY /(EV) 1.03 34 ELONGATION (6) 1.0-I.5 32 BASIS 501 FLE X. STR.
RADI AT ION DAMAGE THRESHOLD (RADS) 1.8E 8 4
COMPRESSIVE STRENGTH (PSI) 20000-35000 32 SHEtF L1FE tYEARS)
F t E XURAL STRE NGTH (PSI )
7000-14000 32 GEDee MX.D PACKAGING: ANSI N45.2.2 LEVEL B IEEDOE MIED STORAE: ANSI N45.2.2 LEVEL B P4ckaged and sealed to protect it from physical damage, water vapor, Stored in clean, dry containers away from ozone contaminates, con ti;sstion and weather during shipping, handling and storage, sunlight, water and dust. The storage temperature should not exceed 120 F.
IIEINAL EFFECTS: (59)
RADIATION EFFECTS:
Moldid parts can withstand Intermittent exposures to temperatures upt to 500 F ; without seriously impairing the physical properties. With Phenolic with asbestos filler shows excellent radiation stability and 0
prolonged exposure, the material has a tendancy to darken and there is unaffected by radiation dos + % up to 3.9 x 10 rads. Such will be some internal crazing.
' combinations also have higher heet stability. Phenotics however, ordinarily deteriorate when exposed to elevated temperatures in the COCATIIlt lTY DIARACTERISTICS: (61) presense of air due to oxidation. Irradiation inhibits oxidation which results in further crosslinking.
Unstfacted by most concentrations of inorganic acids. Excellent resistmce to weak acids and weak alkalles. They are insoluble in HICH TDSTRATINE 18ATER ENVIR0leENT EFFECTS:
most aliphatic, aromatic and halogenated hydrocarbons. They are resistant to gasoline, mineral and vegetable oils artd lubricants.
Unaffected by water at high temperature.
Poorly resistant to oxidizing agents.. Surface darkens on exposure to sunlight. Very low moisture absorption.
TYPICAL TRADE NADE(S):
AfYtICATIONS:
Durez BakeIite litndles and knobs, electrical switchgear, home and commercial wiring Haveg' (Haveg 41) deviccs.
F i bcr i t e GENERIC NAME : Phenolic Asbestos Fill CHE MICAL NAME : Phenol formaldehyde Asbestos Fill i
No.
References 19.
MIL-R-83248, Rubber, Flourocarbon Elastomer, High Temperature, Fluid; and Compression Set Resistant, 19 Nov. 1969.
20.
MIL-R-83248/1A (USAF), RUBBER, Flourocarbon Elastomer, High Temperature, Fluid,-and Compression Set Resistant, O' rings, Class 1, 75 Hardness,. 10 July 1975.
21.
MIL-R-83412A (USAF), Rubber, Ethylenepropylene, Hydrazine Resistant.
22.
MIL-B-121E, Barrier Material, Greaseproofed, Waterproofed, Flexible.
23.
MIL-G-0021032E (SHIPS), Gaskets, Metallic Asbestos, Spinal Wound.
24.
7342167 Bulletin, Precision Rubber Products.
25.
0199200 Bulletin, Acushnet Co., 0-Ring Standard Size and Tolerances.
26.
6224729 Bulletin, Minnesota Rubber Co., " Quality Control A Verification."
27.
American Society for Testing and Materials D2240-81 Standard Test Method for Rubber Property - Duometer Hardness, 1981.
28.
American Society for Testing and Material D-1415-81 Standard Test Method for Rubber Property - International Hardness.-
29.
Quality Assurance Requirements for Nuclear Power Plants.
ANSI /ASME NQA-2-1983, The American Society of Mechanical Engineers, 1983.
30.
Parker 0-Ring Handbook ORD-5700, Panker Seal Group, 0.
Ring Div.
31.
National 0-Ring Engineering Manual.
DY-0-10-0182, 1982, National 0-Rings.
32.
Modern Plastics Encyclopedia, 1983-1984.
33.
Kirk-Othmer. Encyclopedia of Chemical. Technology, Vol. 1
--Vol. 16, Interscience Publishers (John Wiley & Sons);
NY.
34 Wyle Laboratories, Material Aging Data Book.
No.
References 48.
NUREG-CR 3629 SAND 83-2651 The Effect of Thermal and Radiation Aging Simulation Procedures on~ Polymer Properties, April 1984.
49.
Fink and Beaty " Standard Handbook for Electrical Engineers" McGraw Hill Book Co.,-llth Edition, 1978.
50.
R. A. Youmans and G. C. Masen " Correlation of Room Temperature Shelf Aging with Accelerated Aging" Industrial and Engi.neering Chemistry, 47(7), July 1955, Pages 1487-1490.
51.
E. E. McLveen, V. L. Garrison and G. T. Dobrowoski
" Class 1E Cables for Nuclear. Power Generating Stations" IEEE Transactlons on Power Apparatus and Systems PAS-03(4), July / August 1974, Pages 1121-1132.
52.
J. E. Theberge, B. Arkels and P. Cloud "How Time and Heat Affect Properties of Plastics" Machine Design, March 1975, Pages 79-81.
53.
J. F. Kircher and R. E. Bowman "Effect of Radiation on~
Materials and Components", Reinhold Publishing Co., New York, 1964.
54
" Thermal Degradation of Organic Polymers" S. L. Modorsky Interscience Publishers'(John Wiley & Sons) New York, page 258.
55.
Demonstration of 40 Year Life for Materials - Arrhenius Data Okonite Co.
56.
R. Harrington " Elastomers for Age Air Radiation Fields Part IV:
Effects of Gamma Radiation on Miscellaneous Elastomers and Rubber Like Plastic Materials" Rubber Age, June 1958, pages 472-481.
57.
Kerite Co. Engineering Data, Exhibit A, dated July 7, 1976.
'58.
R. Harrington, " Elastomers for Use in Radiation Fields, Part IV:
Effects of Gamma Radiation on Miscellaneous Elastomers and Rubber Like Plastic Materials", Rubber Age, June 1958, pp. 472-481.
59.
Handbook of Common Polymers, N. J. Roff and J. R. Scott CRC Press, 1971.
60.
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1 Radiation Effects on Organic Materials in' Nuclear Plants NP 2129 Research Project 1707 3 Final Report. November 1981 Prepared by GEORGIA INSTITUTE OF TECHNOLOGY s^
Nuclear Engineering Department Neely Nuclear Research Center 900 Atlantic Drive. N.W.
Atlanta, Georgia 30332 L
Principal Investigators I.
M. B. Bruce M. V. Davis i
t I
I i
l Prepared for Electric Power Research Institute i
3412 Hillview Avenue Palo Alto. California 94304 EPRI Project Manager j
G. Sister Risk Assessment Program l
Nuclear Po.ver Division l
more radiation resistant than those cured with aliphatic amines or acid anhydrides; threshold damage occurred at 109 rads and 2 x 108 rads, respectively. Novalac has been found to be quite resistant to oxidation while many others are not. A combined environment of heat and radiation was found to be less severe than heat alone for one epoxy laminate.36 Electrical properties show some variation from exposure to radiation environments, but are of adequate stability for use in most electronic circuits.36 Phenoxy Resins / threshold - unknown Though chemically similar to epoxy formulations, radiation resistances of phenoxy resins appear to be generally less than that of epoxies. One test indicated a loss of 75% of the initial tensile strength after 3 x 108 rads with most of the material's ductility also lost.55 Furane Resin / threshold - 3 x 108 rads / tensile / elongation.
Duralon, an asbestos and carbon black-filled, furane-based resin, shows very good radiation resistance. The properties measured (tensile and impact strength, elongation, and elastic modulus) showed initial degradation at 3 x 108 rads and 25% damage at 3 x 109 rads.37 Phenolic Resins / threshold - 3 x 105 to 3.9 x 108 rads / elongation Unfilled and cellulose-filled phenolics _are not particularly radiation resistant and after irradiation become more susceptible to moisture damage and disintegration. Phenolic laminates and mineral-filled phenolics exhibit very good stability in radiation fields. Phenolic laminates irradiated at temperatures as high as 9000F retain flexural strength as good as or better than nonirradiated controls. Oxidation may be inhibited by radiation-induced reactions in this case.36 Electrical properties are generally stable to high doses. Transient increases in leakage resistance of a factor of 10 have.been noted in conhectors utilizing phenolics, but recovery to original values was rapid.33 The least resistant phenolic resin reported was linen fabric-filled, with 25% damage shown et 3 x 105 rads. The most resistant was asbestos-filled (Haveg 41), with 25%
damage after 3.9 x 109 rads.36 Graphite fillers do not appear to be effective with phenolics. Graphite-filled Karbate exhibited threshold damage at 8 x 105 rads. Some phenolic laminates have been found unaffected by as much as 8 x 109 rads.
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M I o-THE EFFECT OF NUCLEAR RADIATION ON c.:t ELASTOMERIC AND PLASTIC COMPONENTS
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4 152 Phenolic laminates tested by Keller(9) haYaot reached threshold damsge after a room-temperature exposure to 8.3 x 1011 ergs 3-1 (C). Even after the irradiated lami-nates were heated for 1/2 hour at 500 F, flexural strengths were high, approximately 47,000 psi. Nee values were equivalent to the Sexural strength of ammirradiated lami-l nates exposed to 500 F for 1/2 hour (see Table 19).
Phenolic laminates irradiated to an exposure dose of 2.1 x 10' orgs 3*I (C) at tem.
600, 700, 400, and 900 F ahowed equivalent or h'.gher Samaral-strength peratures of values than laminates heated to these temperaenres with no irradiation.(9,83) Kauer points out that a phenotic systeen ordinatuy deteriorates when exposed to elevated tem-peratures in the presence of air due to oxidation.
He suggests that it is possihte that irradiation inhibits the oxidation and that cross 11aking takes place.
Epoxy Ztesias.
When cured, epoxy resias are generany hard, entsemely tough, and chemicany inert.
They are the reaction products of epichlorebydria and poly-hydroxy corapounds (usually bisphenot-A) and are used as encapsulating resias for electrical parts, for protective coatings, and as bladers for kannimates.
mee resias are above average for plastics in radiation resistance, having with-stood doses up to 9.5 x 10 0 1
ergs g-1 (C) without deterioration. This is very likely due to their rigidity and aromatic content. It is an exam come the effects of the quaternary carbon atosa.(112,ple of how great rigidity can over-161)
Aitken and Ralph (162) summarised work on the effect of pulse radiation on cast l
epoxide resia systems. The samples were irradiated with a slow neutron fluz ranging between 9 x 1011 amd 1. 2 x 1012 a cm-1 sec*1, the latter figure being the maximum l
flux available. All results are expressed as days at pue factor 12.
Most of the flexural strengths reported consist of only one break at es,ch level of irradiation.
This is not sufficient to obtain any degree of certainty but it does indicate which are the best systems to study further. In the systems in which more than one test was carried out, it is obvious that the variance about the sample mean is increased by irrediation. This has been confirmed in later work not yet reported.
Although hardness measurements were carried out on a large number of samples, the change of hardness with irradiation was sman compared with the experimental error -
of the measurement.
Similarly the shrinkages reported were==all comnpared with the error in measurement and the slight variation la sample thicknesses.
First results showed, as expected, that the aromatic amine hardners produced considerably more-radiation-resistant systems than the aliphatic amines. Breakdown in-these latter cases consisted of rapid fall off la flexural strength as the irradiation pro-coeded, and of the weret cases of formation of gas h11sters in the amanples.
There appears to be a connection between heat-distortion point (HDP) and radia-tion resistance.
The rotational and flexural freedom of the methylenic structure of an aliphatic amine produces cast resias with low heat-distortion points and, conversely,
~
the rigidity of the aromatic hardeners leads to high HGP's and increases resistance to radiation effects.
The initial increases in flexural strength observed la some systems are probably caused by the reaction of the residual ethoxyline groups under the influence of radiation.
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