ML19290C088
| ML19290C088 | |
| Person / Time | |
|---|---|
| Issue date: | 06/11/1979 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19290C086 | List: |
| References | |
| REF-GTECI-A-24, REF-GTECI-EL, TASK-A-24, TASK-OR NUDOCS 8001090146 | |
| Download: ML19290C088 (100) | |
Text
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INTERIM STAFF POSITION ON ENVIRONMENTAL QUALIFICATION OF SAFETY RELATED ELECTRICAL EQUIPMENT Introduction Equipment that is used to perform a necessary safety function must be capable of maintaining functional operability under all service conditions expected to occur during the installed life for the time it is required to operate. This requirement is applicable to equipment located inside as well as outside containment.
The methods, procedures and guidelines for demonstrating this capability have been set forth by industry in IEEE Std 323 and ancillary standards (e.g., IEEE Stds. 317, 334, 382, 383) and endors ed, as noted in Regulatory Guides, by the NRC.
The basic requirements established in these standards include the principles, procedures and methodology guidelines.for qualification. They provide guidance for demonstrating and documenting qualification of safety related equipment to satisfy the ceneral requirements which are embodied in General Design Criteria 1, 2, 4 and 23 of Appendix A and Section III and XI of Appendix B to 10 CFR Part 50.
The development of these standards has been evolutionary in nature and the qualification requirements contained therein were subject to interpretation,
As a result, the methods used to qualify equipment have varied.
1730 227 8001090
'e
ii The staff review of the proposals and practices of equipment suppliers and license applicants indicate that some have developed qualification programs which are generally acceptable. The efforts of others, as compared with the " state of the art," need further improvements.
Several aspects of equipment qualification are Ning pursued at this time by the NRC staff and the nuclear industry to achieve a more uniform interpretation and implementation of the qualification requirements.
- But, because of the diversity of the programs being developed and until such time when the generic resolution of equipment qualification is achieved, an interim NRC position specifying how the requirements may be satisfied is needed.
Only selected areas of qualification are addressed in this report.
Guidance is provided regarding methods which, when implemented properly, will satisfy the requirements set forth in the referenced standards.
Alternatives may be proposed which may also satisfy those requirements and they will be evaluated on a case-by-case basis.
While the intent of the interim staff positions is to define criteria related to the functional performance of electrical equipment under applicable service conditions, it is necessary to recognize interfaces in its qualification process.
1730 228
-iii-Current on going studies on organic materials, such as those used in cable insulation and jacketing are being evaluated as potential sources of combustible gas and chloride (during a'DBA). Also, aging, synergistic and sequential environmental effects on selected safety related equipment are being evaluated. The assumptions made by the staff in arriving at these interim positions may be overly conservative, pending completion of ongoing studies and tests by the NRC and industry,and future staff positions which are developed as a result of ongoing activities may require changes to the interim positions. However, in view of the need for guidance to allow an orderly and systematic implementation of long term equipment qualification programs in industry, and in order to provide guidance within the NRC staff for use in the ongoing licensing reviews, this interim action is warranted.
It should be noted that these positions have been developed prior to the TMI-2 event and any additional requirements or modifications to these positions will be identified in a supplemental report.
Seismic qualification, which is being pursued generically, and on a case basis, via the Seismic Qualifi-cation Review Team (SQRT) is outside the scope of this document.
Discussion Regulatory Guide 1.89 specifies that, for plants for which a construction permit safety evaluation report was issued prior to July 1, 1974, the qualification programs to qualify safety related equipment shall be developed and evaluated on the basis of conformance to the requirements established in IEEE Std 323-1971 "IEEE Trial-Use Standard:
" General Guide for Qualifying Class lE Electric Equipment for Nuclear Power 1730 229
-iv-Generating Stations".
For plants for which a construction permit safety evaluation report was issued after July 1, 1974, the qualification programs to qualify safety related equipment shall be developed and evaluated on the basis of conformance to the requirements established in IEEE Std 323-1974, "IEEE Standard for Qualifying Class lE Equipment for Nuclear Power Generating Stations".
For safety related equipment which was purchased after November 15, 1974, irrespective of the construction permit safety evaluation report issue date, the applicants and licensees should qualify this equipment to the requirements established in IEEE Std. 323-1974.
For plants undergoing an Operating License review, the staff evaluates qualification documentation on selected safety related equipment. The objective of this review is to establish that reasonable assurance has been provided that the equipment can perform its intended function in the most limiting environment in which it is expected to function. To facilitate this review, the applicants which utilized this equipment are required to submit in an auditable form the necessary information which demonstrates adequate qualification in conformance with applicable Standards and Regulatory Guides. That information, together with an adequate degree of conformance with the positions provided in the following sections (which reflect the staff view of what is required in order to satisfy the regulatory requirements) will expedite the environmental qualification reviews.
1730 230
Interim Staff Position for Environmental Qualification of Electric Equipment N
CATEGORY II CATEGORY I Plants with CP SER's Issued After Plants With OL Applications July 1, 1974 or Equipment Purchased Currently Under Staff Review After Novemher 15, 1974 and CP SER Issued Prior to July 1, 1974 I.
Qualification Parameters Inside Con-tainment IA. Temperature and Pressure for LOCA IA. Temperature and Pressure for LOCA Condi tions Conditions 1.
The temperature and pressure as'a func-1.
Same as Category I.
tion of time established for the design of the containment structure, and found acceptable by the staff,may be used for environmental qualification of ei,uipment.
[ Margins should be added when qualification testing is performed to assure that these containment design parameters have been enveloped and to provide additional confidence of equipment ade-quacy when type test of orie is used.]
prev 4ded-apprepriate-margins-are-added.
2.
In lieu of using the plant specific
- 2. [Same as Category I]
containment design profiles [for BWR and ICE Condenser type plants] phs-margin, the generic envelope shown in Appendix 8 1730 231
CATEGORY I CAltGURY 11 Plants with CP SER's Isst ad After Plants With OL Applications July 1, 1974 or Equipment Purchased Currently Under Staff Review After November 15, 1974 and CP SER Issued Prior to July 1, 1974 may be u ed [for qualification testing] with no addition margins required [since they are included in the prescribed curves] pre-vided-it-ean-be-desenstrated-that-the-plaRt s p ee i f ie -d e s i g n - pa Fare te F s -d e - Re t-e x e eed - t h e vahes-skewar 3.
Acceptable methods for calculating and
- 3. [ Same as Category I ]
establish [ing] tre containment pressure and temperature er.vironment response envelope for which safety related equipment should be qualified to is summarized below. Accep-table methods for calculating mass and ener-gy release rates are summarized in Apperdix A. [ Attachment 1]
PWR's Dry Containment - Calculate LOCA containment
[ Dry Containment environment using CONTEMPT-LT or equivalent Use the same containment models as in industry codes (additional guidance is pro-Category I.
Certain assumptions such as vided in Section 6.2.1.1.A of the Standard partial revaporization will be allowed on Review Plan),
a specific plant type basis. Other assumptions which reduce tre temperature response of the containment will be evaluated on a case-by-case basis.]
1730 232 2
CATEGORY I CATEGORY II Plants with CP SER's Issued After Plants With OL Applications July 1, 1974 or Equipment Purchased Currently Under Staff Review After November 15, 1974 and CP SER Issued Prior to July 1, 1974 s
I_ce Condenser Containment - Calculate LOCA
[ Ice Condenser Containment containment envirorment using LOTIC or Same as Cattgory I]
equivalent industry codes (additional gui-dance is provided in Section 6.2.1.1.B of the Standard Review Plan).
BWP's
[BWR's Mark II and III Containment - Calculate LOCA Same as Category I]
environment using methods of GESSAR Appendix 3B or equivalent industry codes (additional guidance is provided in Section 6.2.1.1.c of the Standard Review Plan).
IB.
Submergence and Chemical Spray
[IB. Submergence and Chemical Soray]
1.
Safety related equipment should be iso-1.
Same as Category I lated from effects of submergence by enclosing the equipment in[ qualified] water tight compartments or located above flood level. Where this is [not] part practicable,
[the] th4s equipmt.at should be identified and demonstrated to be qualified [by test]
for the duration required.
2.
The effects of caustic spray shnulti he 2.
Same as Category I addressed, and sked d-be incorporated during [ simulated event] EOGA-testing.
1730 233 3
CATEGORY I CATEGORY II Plants with CP SER's Issued After Plants With OL Applications July 1, 1974 or Equipment Purchased Currently Under Staff Review After November 15, 1974 and CP SER Issued Prior to July 1, 1974 s
3.
The crustics used during testing should
- 3. [ Same as Category I ]
be equivalent to or more severt than those used in the containment spray system. See Standard Review Plan (SRP) Section 6.5.2 para-graph II [ item (e)] for [caurtic] spray
[ solution] system guidelines.
IC. Temperature and Pressure for MSLB IC.
Temperature ard Fressure for MSLB Conditions Conditions 1.
The [ environmental] gealificatien para-1.
Where qualification has been completed meters [used for qualification] should be but only LOCA conditionr were considered, then calculated with a plant specific model it must be demonstrated that the LOCA quali-(ineluding-quantifiee-margins) reviewed and fication conditions exceed or are approved by the staff prior to issuance of the equivalent to the maximum calculated MSLB Operating License SER.
[Appropriatemargins conditions. The following technique is should be added to envelope these parameters acceptable; when qualification testing is perfomed.]
a.
Calculate thE peak temperature frCm a MSLB using a model based on the staff's approved assumptions discussed in item 1 of Appendix A (Attachment 2).
b.
[Same as Category I]
[IC4(c)]
Shew-that-the-peak-surface-tempeFateFe--ef the-eespenent-te-be-quam fied-kas-net 1730 234 4
CATEGORY I CATEGOR' II Plants with CP SER's Issued After Plants With OL Applications July 1, 1974 or Equipment Purchased Currently Under Staff Review After November 15, 1974 and CP SER Issued Prior to July 1, 1974 exceeded-the-h0GA-qualificatien-temperature by-t h e -me the d -d i s eus sed -in -i tem-2-e f-Ap pe n d i x A-(Attaehment-2).
c.
If the calculated surface temperature exceeds the actual qualification temperature
[the staff] we-will require [s] that;
- 1) additional justification be provided to demonstrate that the component can maintain its required functional operability in the environments associated with the calctlated peak surfar,e temperature, or 2) r(qualifica-tion testing be performed with appropriate margins, or 3) qualified physical protec-tion be provided to assure that the surface temperature will not exceed the ictual qualification temperature.
2.
Models which are acceptable for calculat-ing [containmant] these parameters are listed in IA [3] abever 1730 235 5
CATEGORY I CATEGORY II Plants with CP SER's Issued After Plants With OL Applications July 1, 1974 or Equipment Purchased Currently Under Staff Review After November 15, 1974 and CP SER Issued Prior to July 1, 1974
[3.
In lieu of using the plant specific con-tainment design profiles [for BWR and Ice the Condenser type plants] plus-margin s generic envelope shown in Appendix B may be used [for qualification testing] with no additional margins required since they are included in the prescribed curvess-prev 4ded 4t-ean-be-demenstrated-th&t-the-plant-Spe64-fie-design-parameters-de-net-exeeed-the-vahe s shewn--]
[4a. Where qualification has been completed but only LOCA conditions [are] were con-sid' ed, then it murt be demonstrated thzt the LOCA qualification conditions exceed or are equivalent to the maximum calculated MSLB conditions. The following technique is acceptable.]
[b. Calculate the peek temperature en lope iDO 86 from a MSLB using a model based on the staff's approved assumptions defined in IA(3).]
[c. Show that the peak surface temperature of the component to be qualified has not exceeded the LOCA qualification temperzture 6
t
CATEGORY I CATEGORY II Plants with CP SER's Issued After Pla.ts With OL Applications July 1, 1974 or Equipment Purchased Currently Under Staff Review After November 15, 1974 and CP SER Issued Prior to July 1, 1974 by the me'thod discussed in item 2 of Appen-dix A (Attachment 2).]
[d.
If the calculated surface temperature exceeds the actual qualification temperature
[the staff] we-will require [s] that;
- 1) requalificction testing be perfcrmed with appropriate margins, or 2) qualified phy-sical protection be provided to assure that the surface temperature will nct exceed the actual qualification temperature. For selected early plants where compliance with 1 or 2 above represents a substantial hard-ship the staff will consider additional justification of equipment adec;uacy on some other defined basis.]
ID; Radiation Inside and Outside Contain-ID. Radiation Inside and Outside Containment ment Same as Category I The following positions and sample cal-culations (in Apper. dix C) provide an acceptable apprcach to establish radia-1730 237 tion limits for quzlification. Addi-tional radiation margins identified in 7
CATEGORY I CATEGORY II Plants with CP SER's Issued After Plants With OL Applications July 1, 1974 or Equipment Purchased Currently Under Staff Review After November 15, 1974 and CP SER Issued Prior to July 1, 1974 s
Section 6.3.1.5[of] er IEEE Std 323-1974 for qualification type testing are not re-quired if these methods'are used.
1.
The radiation environment for qualifica-tion of equipment should be based upon both normally expected radiation environment over the intended equipment qualified life, plus that associated with the most severe design basis accident (DBA) during or following which that equipment is designed to remain functional.
It should be assumed that the DBA related environmental conditions occur at that point corresponding to the maxinium intended equipment life.
2.
In lieu of an analysis supporting a lower value found acceptable by the staff, the source tem to be used in determining the radiation environment assoc ated with the i
design basis LOCA should be taken as an in-stantaneous release from the fuel of 100%
238 of the noble gases, 50% of the halogens and 1 :
of the remaining fission products; for all other design basis accident conditions, a source term involving a release from the fuel of 105 of the noble gases (except Kr-85 8
CATEGORY I CATEGORY II Plants with CP SER's Issued After Plants With OL Applice; ions July 1, 1974 or Equipment Purchased Currently under Staff Review After November 15, 1974 and CP SER Issued Prior to July 1, 1974 for which a release of 30% should be assumed) and 10% of the halogens is acceptable.
3.
The calculation of the radiation environ-ment associated with design basis accidents should take into account tre time-dependent transport of released fission products with-in various regions of containment and auxi-liary structure s.
4.
Effects of ESF systems, such as con-tainment sprays and cor.tainment ventilation und filtration systems, which act to remove airborne activity and redistribute activity within containment should be calculated using the same assumptions as used in the calculation of offsite dose (see SRP section
'5.6.5 and related SRP's referenced in the Appendices to ttat SRP section).
1730 239 5.
Natural deposition of airborne activity should be modeled using a mechanistic model and best es,timates for model parameters.
The assumption of 25% instantaneous plate-out of iodine should nc.t be made. Removal of iodine from surfaces by steam condensate 9
flow or wash-off by the containment spray
CATEGORY I CATEGORY II Plants with CP SER's Issued After Plants With OL Applications July 1, 1974 or Equipment Purchased Currently Under Staff Review After November 15, 1974 and CP SER Issued Prior to July 1, 1974 may be assumed if st.ch effects can be reasonably quantified by analysis or ex-periment.
6.
The initial distribution of activity within the containment should be based on a mechanistically rational assumption.
Hence for compartmented containments, such as in a BWR, the source should be assumed to be initially contained in the drywell.
The assumption of uniform distribution of activity throughout the containment at time zero is not appropriate.
7.
The radiation environment that specific equipment may experience should consider factors as the time varying location and concentration of fission products, local anc structural shielding, attenuation in air, water, and encapsulating materials (such as sheat[h]ing of cables).
1730 240 8.
The unshielded gmna dose rate for equip <
ment located at any point in the contain-ment should be based on the dose and dose rate at the center of the region, unless analyses of the reduction in dose and dose e
10
CATEGORY I CATEGORY II Plants with CP SER's Issued After Plants With OL Applications
' July 1, 1974 or Equipment Purchased Currently Under Staff Review After November 15, 1974 and CP SER Issued Prior to July 1, 1974 rate due to spatial location and shie! ding are provided.
9.
The unshielded beta doses on the sur-face of the equipment or coating should be based on the sum of the airbone and plate-out scurcas. The airborne beta dose should be taken to be one-half the beta dose cal-
~
culated for an infinite cloud.
10.
In judging the qualification of Class IE equipment with respect to the radiation environment associated with a design basis LOCA, the staff w'll accept a given compo-nent to be qualified provided the appli-cant can show that the component has been qualified to integrated beta and gamma doses which are equal tc or higher than those levels resulting from an analysis per formed by the applicant, similar in nature and scope to that inclujed in the Appendix [C], (which uses the source term 1730 241 given in 2 above), and incorporates appro-priate factors pertinents to the plant design and operating characteristics, as given in these general guidelines.
11
CATEGORY I CATEGORY II Plants with CP SER's Issued After Plants With OL Applications July 1, 1974 or Equipment Purchased Currently Under Staff Review After November 15, 1974 and CP SER Issued Prior to July 1, 1974 11.
In lieu of an analysis by the appli-cant, the staff will use the radiation environ-ment estimates contained in the Appendix [C]
with suitable correction for differences in reactor power level, type, containment size, and other features as appropriate.
- 12. Completely enclosed or shielded componen :s need be qualified only to the gama ray levels required, provided an analysis shows that sen -
sitive portions of the component or equipment are not exposed to beta radiatior., and that the effects of beta ray heating upon the component have been taken into consideration assuring no de!iterious effects on component performance.
[For example, for the base plant criculations (shown in the Appendix
[C]) an appropriately shielded containment pressure sensor ar;d transmitter would re-quire qualification to the gama dose of Table 5.
(See Appendix C)].
1730 242
- 13. Unshielded cables arranged in cable trays in the containment should be assumed to be exposed to half the beta ray environment of that of a point within the containment atmosphere (due to localized shielding of 12
CATEGORY I CATEGORY II Plants with CP SER's Issued After Plants With OL Applications July 1, 1974 or Equipment Purchased Currently Under Staff Review After November 15, 1974 and CP SER Issued Prior to July 1, 1974 other cables plus the cable tray itself),
plus the gama ray environment apprcpriate to the cable tray location. Cables completely shielded from beta rays need be qualified onb to the gamma ray environment provided the considerations of item 1, above, apply.
For the bare case plant, (calculations shown in
[the] Appendix) unshielded containment pressure transmitter cables in the example above would need to be qualified to the beta dose of Table 6 in addition to the gamma dose of Table 5.
(See Appendix C).
The doses that the ECCS equipment outside containment should be qualified to beginning at t=0 are shown, as a function of separation distance, as shown in Tables 9 and 10.
(See Appendix C).
14.
Paints and containment coatings should be assumed to be exposed to both beta and gama rays for a point at the containment 0 243 surface. Plateout activity should be assumed to remain on the surface unless the effects of removal mechanisms such as spray washoff or steam condensate flow can be reasonably 13
rATEGORY I CATEGORY II Plants with CP SER's Issued After Plants With OL Applications July 1, 1974 or Equipment Purchased Currently Under Staff Review After November 15, 1974 and CP SER Issued Prior to July 1, 1974 quantified by analysis or experiment. Paints and containment coatings should be qualified to a radiation envircnment that precluder sloughing off of any coatings or paints into the sump, with possible interference of ECCS recirculation. Minor cracking or blistering of paints or containment coatings that does not interfere with ECCS recirctlation is acceptable. For the base case plant, such coatings should be qualified to one-half the infinte cloud beta dose plus thE plateout contribution as shown for the unwashed base case in Table 7; in addition to the con-tainment centerline gamma dose shown in Table 5.
(See Appendix C).
15.
Seals and electrical equipment in or connected to ECCS pumps ex-containment (RHR mode of operation) should be qualified to withstand the radiation environment assuming containment exposure (taking account of shielding from the radiation inside contain-1730 2tl4 ment), plus exposure to the radiation environment of sump fluid assuming the cir-culation of that fluid consistent with the analysis in Appendix K to 10 CFR Part 50.
14 9
CATEGORY I CATEGORY II Plants with CP SE.'s Issued After Plants With OL Applications
' July 1, 1974 or Equipment Purchased Currently Under Staff Review After November 15, 1974 and CP SER Issued Prior to July 1, 1974 The recirculation mode begins at about time T=30 minutes after initiation of the acci-dent, at which time tne dose contributions from the radioactive sump fluid would be added to the shielded contribution from in-side the containment.
16.
Equipment that may be exposed to 4
radiation doses below 10 rads should not be considered to be exempt from radiation qualification, unless analysis supported by test data is provided to demor. strate that these levels will not degrade the opera-bility of the equipment below acceptable values.
II Temperature [,] and Relative Humidity II Temperature [,] and Relative Humidity Humidity [and other] Environment [s]
Humidity [and otheri Ensironment for for Outside Containment Outside Containment 1.
Safety related equipment located in Same as Category I. or general plant areas outside containment There may be designs where a loss of the where equipment is not subjected to a environmental support system will not com-design basis accident anvironment should promize safety but may expose some safety be qualified to the normal and abnormal related equipment to environments which range of environments expected to occur at exceed the normal qualified limits. For the installed location.
these designs we require that apprcpriate monitoring devices be provided to alert 1730 245 15
CATEGORY I CATEGORY II Plants with CP SER's Issued.fter Plants With OL Applications July 1, 1974 or Equipment Purchased Currently Under Staff Review After November 15, 1974 and CP SER Issued Prior to July i, 1974 2.
The design should assure that the the operator that abnormal conditions exist, environment of the compartments where safety and to aid in assessing the conditions which related ecuipment is located is maintained occurred in order to determine if corrective continuously within the qualified environ-action such as replacing any effected equip-mental limit [s]ed of th equipment.
ment is warranted.
3.
Equipment not served by Class lE en-vironmental support systems [or served by Class lE support systems that may be secured during plant operation or shutdown] should be qualified to the limitinC environmental con-ditions that are expected to occur in that location, assuming a loss of the environ-mental support system.
4.
Equipment outside containment subjected to high energy pipe breaks should be qualified to meet the conditions resulting from the accident for the duration rec,uired. The techniques to calculate the environmental parameters described in items A through D of part I above, should be applied.
III.
Qualification Methods III. Qualification Methods 1.
Qualification Methods should confonn to 1.
Qualification Methods should conform to the requirements defined in IEEE Std 323-tte requirements defined in IEEE Std 323-1971.
1974.
1730 246 16
CATEGORY I CATEGORY II Plants with CP SER's Issued After Plants With OL Applications July 1, 1974 or Equipment Purchased Currently Under Staff Review After November 15, 1974 and CP SER Issued Prior to July 1, 1974 s
2.
The choice of the methods selected is 2.
Same as Category I largely a matter of technical judgement and availability of information which support the conclusions reached.
Experience has shown that qualification without test data for an assembled electrical comporent is not ade-quate to demonstrate functional operability.
In general the staff will not accept analysis in lieu of test data for an assembled electrical component unless; a) testing of the component is impractical due to size limitations and, b) partial type test data is provided to support the analytical assumptions and conclusions reached.
3.
The environmental qualification of safety 3.
Same as Category I related equipment subject to a DBA environ-ment [s] should conform to the following:
a) Equipment that must function in order to mitigate the [an] accident should be quali-fied by test to demonstrate operability in the [ervironmental conditions resulting from 1730 247 thataccident]aseideet-envivenmentfor the time required fer-aecideRt-RitigatieP with safety margin to failure. [See Note *]
17
CATEGORY I CATEGORY II Plants with CP SER's Isstad After Plants With OL Applications July 1, 1974 or Equipaent Purchased Currently Under Staff Review After Novenber 15, 1974 and CP SER Issucd Prior to July 1, 1974 b.
Equipment that need not function [in order to mitigate any] fer accident mitigatien, but that must not fail in a manner detrimental to plant safety or accident mitigation [ requirements,] should be qualified by test to demonstrate the capability to withstand any accident environ-ment for the time during which it must not fail.
Technical bases should be provided for the time interval, the operability criteria specified, and the safety margin to failure.
(See tinto *)
Note * [when establishing the simulated environmental profile for qualifying Class lE equipment located inside containment, it is preferred that a single profile that encompasses the environmental conditions resulting from the limiting events that are postulated to occur during any mode of plant operation be used (e.g. a profile that envelopes the conditions produced by the main steamline break and loss of coolant accidents.]
c.
Equipment that need not function [in order to mitigate any] feF accident mitiga-tien and whose failure in any mode in a[ny]
accident environment is not detrimental to 1730 248 plant safety need only be qualified for its non-accident service environment. Technical bases should be provided to support the claims thEt such equipment is nct. required 18
CATEGORY I CATEGORY II Plants with CP SER's Issted After Plants With OL Applications July 1, 1974 or Equipment Purchased Currently Under Staff Reviec After t;ovember 15, 1974 and CP SER Issued Prior to July 1, 1974 to function for [any] accident mitigation and that its failure in any mode while sub-jct to any accident environment is not 4
detrimental tc plant safet or accident mitigation.
4.
Environmental qualification of safety 4.
Same as Category I related equipment net subject to [other events than] a DBA [which result in abnormal environmental conditions] and for equipment in Category 3C (above) [ actual type testing is preferred. However,] analysis operating history, or any applicable combination presented [thereof], coupled with partial type test may be found acceptable, subject to the applicability and detail of informa-tion provided.
Aetual-type-testing-hewever is-prefetted.
IIIA.
Qualification by Tert IIIA. Qualification by Test 1.
Test results should demonstrate that 1.
Same as Category I the equipment can perfonn its required func-tien for all service conditions expected (wit i 1730 249 margin) during its installed life.
h 19
CATEGORY I CATEGORY II Plants with CP SER's Issued After Plants With OL Applications July 1, 1974 or Equipment Purchased Currently Under Staff Review After November 15, 1974 and CP SER Issued Prior to July 1, 1974 2.
The methedelegies [ items] described in 2.
The methedelegies [ items) described in Section 6.3 of IEEE Std 323-1974 when fully Section 5.2 of IEEE Std 323-1971 when fully implemented constitute acceptable guideline: implemented constitute acceptable guidelines for establishing test pre-dures.
for establishing test procedures.
3.
The actual qualification temperature 3.
Same ;s Category I.
If thermocouples
[is that value experienced during] skeuld-were not used during the tests, (at the be-determined-frem the actual simulated component) heat transfer analysis may test environment. For components that have be used to determine the actual temper-been [ exposed to] (" bathed"in) a saturated ature environment at the component.
steam or steam-air environments in excess (Acceptable heat transfer analysis of 10 minutes, the qualification tempera-methods are provided in Appendix A ture can be considered to be the ambient ).
temperature in the test chamber.
- However, for components subjected to test conditions substantially removed from the steam satura tion point or " bathed" in environments for less than 10 minutes, the qualification temperature should be defined by thermoccup e readings on the component surface.
4.
Performance characteristics of equip-4.
Same as Category I ment should be verified before, after and periodically during testing throughout its 1730 250 range of required operability.
20
CATEGORY I CATEGORY II Plants with CP SER's Issued After Plants With OL Applications July 1, 1974 or Equipment Purchased Currently Under Staff Peview After November 15, 1974 and CP SER Issued Prior to July 1, 1974' 5.
Continuous monitoring of equipment 5.
Same as Category I status during test is preferred [ required].
For long term testing [however,] monitoring at reasonably descrete intervals may be found acceptable.
6.
Expected extremes in power supply vol-6.
Same as Category I tage range [and frequency] should be applied during [ simulated event] E9EA/MSEB environmental testing.
7.
Dust environments should be addressed 7.
Same as Category I when establishing qualification service conditions and included during testing.
IIIB. Margins IIIB. Marcins 1.
Quantified margins should be provided 1.
Same as Category I and accounted for in the testing of safety related equipment.
2.
In lieu of other proposed margins 2.
The margins provided in the design will that may be found acceptable, the be evaluated on a case by case basis.
[suggestedvaluesindicated] guidelines Factors that should be considered in quantify defined in IEEE 323-1974 Section 6.3.1.5 ing margins are; 1) the environmental stress levels induced during testing, 2) the should be used [as a guide] (Note excep-tions stated in Itet IA4[2] [,] [IC3],
duration of the stress levels, 3) the number ID and in [the] Figure 4-ef [in] Appendix of tests performed in the hostile environment
- 4) the performance characteristics of the B).
1730 251
CATE'ORY I CATEGORY II Plants witi CP SER's Issued After Plants With OL Applications July 1, 1974 or Equipment Purchased Currently Under Staff Review After November 15, 1974 and CP SER Issued Prior to July 1, 1974
\\
equipment while subjected to the environmental stresses, and 5) the specific function of the equipment. (See-additienal-guidanee-is-ites-IA and-19-abeve-aRd-iR-Figuice-l-ef-AppeRdix-8).
3.
Some equipment may be required by the 3.
Same as Category I or a technical basis design to only perform its safety function should be provided for the adequacy of the within a short time period into the aseident margins specified with safety margins to
[ event] (i.e., within seconds or minutes), and failure described.
once its function is complete subsequent failures can be shown not to be detrimental to plant safety.
Equipment in this category are required to remain functional in the acci-dent environment for a period of at least one (1) hour in excess of the time assumed in the accident analysis.
For all other equipment (e.g., post accident monitoring) the 107, time margin identified in IEEE Std 323-1974 may be used.
IIIC. [ Test] Sequence IIIC. [ Test] Sequence 1.
The test program should conform fully to 1.
Justification of the adequacy of the the guidelines established in Section 6.3.2 of test sequence selected should be provided.
IEEE Std 323-1974. The test procedures should insure that the same piece of equipment is used throughout tre test sequence.
1730 252 22
CATEGORY I CATEGORY II Pian 6..ith CP SER's Issned After Plants With OL Applications July 1,1974 or Equipment Purchased Currently Under Staff Review After November 15, 1974 and CP SER Issued Prior to July 1, 1974 2.
The test procedures should conform to the guidelines described in Section 5 of IEEE 323-1971.
3.
The test sequence should simulate as close as practicable the expected environment 4.
The suggested sequence described in the 1974 revision of the standard is considered the most severe sequence for equipment in-side containment and may be used in lieu of others proposed and found acceptable.
The staff considers, however, that for vital electrical equipment such as penetrations, connectors, cables, valves and motors and transmitters located inside containment
[or exposed to hostile envircnments outside containment, qualification utilzing] separate effects testing (for the most part) is not an acceptable qualification method. As a minimum we require that [the] testing [of such equipment] be conducted in a manner that subjects the same piece of equipment to radiation and hostile environment (e.g.LOCAand/orMSLB) sequentially.
1730 253 23
CATEGORY I CATEGORY II Plants with CP SER's Issued After Plants With OL Applications July 1, 1974 or Equipment Purchased Currently Under Staff Review After November 15, 1974 and CP SER Issued prior to July 1, 1974 IIID. Aging IIID. Aoina 1.
Aging effects on all equipment which 1.
Qualification programs that are committed is required to protect the health and safety to confom to tFe requirements of IEEE Std of the public regardingless of its location 382-1972 for valve operators, and IEEE Std in the plant should be considered and included 334-1971 for motors should consider in the qualification progrzm.
the effects of aging.
[For these designs, Tthe category I positions of IIID are applicable.
2.
The degrading influences discussed in 2.
Documertation for other qualification Section 6.3.3, 6.3.4 and 6.3.5 of IEEE Std programs for safety related equipment need 323-1974 and the electrical and mechanical not specifically address aging. Additional stresses associated with cyclic operation discussion and basis for this position is of equipment should be considered and incluc'ed provided in NUREG-0458.
as part of the aginc programs.
3.
Synergistic effects should be considered in the accelerated aging programs. [Investiga-tion should be performed to assure that no kno wn synergistic effects have been identified on materials that are included in the equipment being qualified. Where synergistic effects have been identified they should]As-a-m4Rimum-th e-eemb 4 Red-e f f e c ts -e f-Fadi a ti e R - a R d-tem p e Fa -
]f3 ture-sheuld-be accounted for in the quali-fication programs.
[ Refer to NUREG/CR-0276 24 (SAND 78-0799), NUREG/CR 0401 (SAND 78-
CATEGORY I CATEGORY II Plants with CP SER's Issued After Plants With OL Applications July 1, 1974 or Equipment Purchased Currently Under Staff Review After November 15, 1974 and CP SER Issued Prior to July 1, 1974 1452) Qualification Testing Evaluation Quarterly Reports] 00673 L'An-Experimental investigatien-ef-Synergisms-in-61 ass-1 Gempenents" for additional information].
4.
The Arrhenius methodology is considered an acceptable method of addressing accelerated aging. Otter aging methods which can be supported by type tests will be evaluated on a case by case basis.
5.
Known material phase changes and reac-tions shocid be defined to insure that no known changes occur within the extrapola-tion limits. Justification for tte selectior of e[a]n aging acceleration rate should be provided.
6.
Periodic surveillance testing under normal service cor.ditions is not considered an acceptable method for on-going quali-fication unless the plant design includes provisions for subjecting the equipment 1730 253
/
to the limiting derign transients
[ environments] it is expected to see (specified in Section 3(7) of IEEE 279-1971) during such testing.
25
CATEGORY I CATEGORY II Plants with CP SER's Issued After Plants With OL Applications
' July 1, 1974 or Equipment Purchased Currently Under Staff Review After November 15, 1974 and CP SER Issued Prior to July 1, 1974 7.
Effects of relative humidity need not be considered in the aging of electrical cable insulation.
8.
Cobalt 60 is an acceptable radiation source fcr environmental qualification.
9.
Qualified life is considered a best esti-mate approach and should be ertablished based on tFe severeity of the terting performed, the conservatisms employed in extrapolation of data, operating history and other margins that may be reasonably assumed, coupled with good engineering judgment IIIE. Other Qualification Methods IIIE. Other Qualification Methods Qualification by analysis or or.erating Same as Category I [except that IEEE Std experience [ implemented as] described in 323-1971 and ancillary standards endorsed at the-reference-standards 3[IEEE Std 323-1974, the time the CP SER was issued may be used.]
and other ancillary standards 9FeVieWSlys-preVide guidelines-whiek-when-preperly-4mplemented may be found acceptable. The adequacy of these methods will be evaluated on the basis 1730 256 of the quality and detail of the ir.ft-3 tion submitted in support of the assumptions made and the specific function and location of the 26
CATEGORY I CATEGORY II Pit,its with CP SER's Issued After Plants With OL Applications Juiy 1, 1974 or Equipment Pt.rchased Currently Under Staff Review After November 15, 1974 and CP SER Issued Prior to July 1, 1974
\\
equipment. These methodt are most suitable for equipment where testing is pre-cluded by physical size of the equipment being qualified.
It is expeeted [ required ]
that,when these methods are employed, some partial type terts on vital components of the equipmenti-as-a-minimums [will] be provided in support of these [ analytical]
methods [used].
IV.
Qualification Documertation IV. Qualification Documentation 1.
The staff maintains the 1.
Same as Category I industry position stated in IEEE 323-1974 thzt, "The qualification documentation shall verify that each type of electrical equipment is qualified for its applica-tion and meets its specified performance requi rerrents.
The basis of qualification shall be explained to show the relation-ship of all facets of proof needed to support adequacy of the complete equipment.
1730 257 Data used to demonstrate the qualification of the equipment shall be pertinent to the application and organized in an auditable form."
27
CATEGORY II CATEGORY,,I_
Plants with CF SER's Issued After Plants With OL Applications July 1, 1974 or Equipment Purchased Currently Under Staff Review After November 15, 1974 and CP SER Issued Prior to July 1, 1974 2.
The guidelines for documentation in 2.
Same as Category I except the guidelines IEEE 323-1974 when fully implemented are of IEEE 323-1971 may be used.
acceptable previded[T]he documentation
[should] includes the information [ required]
in Appendix H [for staff review].
In addition, fer-plant-designs-whiek-requirre
[when addressing] aging te-be-addressed during qualification, the follow-ing should be incluc'ed:
a) Specificatior of the design [ qualified]
life of the equipment (and/or component as applicatle) and the basis for its selection.
b) Specification of the aging accelera-tior. rate used during qualification testing ard the basis upon which the rates-were [was] established.
1730 258 28
APPENDIX A (ATTACHf1ENT 1)
Acceptable methods for calculating the mass and energy release to determine the LOCA environment for PWR and BWR plants are described in; A.
Topical Report WCAP-8312A for Westinghouse plants B.
Section 6.2.1 of CESSAR System 80 PSAR for Combustion Engineering plants C.
Appendix 6A of B-SAR-205 for Babcock & Wilcox plants D.
NED0-10320 and Supplements 1 & 2 for General Electric p; ants-Acceptable methods for calculating the mass and energy release to determine the Main Steamline Break (MSLB) environment are described in; A.
Appendix 6B of CESSAR, System 80 PSAR for Combustion Engineering plants B.
Section 15.1.14 of B-SAR-205 for Babcock & Wilcox plants C.
Same as item D above for General Electric plants D.
Topical Report WCAP-8822 for Westinghouse plants.
(Although this Topical Report is currently.under review, the use of this method is acceptable in the ' interim if no entrain-ment is assumed.
Reanalysis may be required following the staffs review of the entrainment model as presently described).
1730 259
1 APPENDIX A (ATTACHi1ENT 2)
Interim Evaluation Model for Environmental Qualification for Loss-of Coolant Accident and Main Steam line Breaks Inside PWR and BWR Dry Type Containments
_l.
Methodology to determine the Containment Environmental
Response
For heat transfer coefficient to the heat sinks,the Tagami con-a.
densing heat transfer correlation should be used for a LOCA with the maximum heat transfer rate determined at the time of peak pressure or the end of primary system blowdown. A rapid transition to a natural convection, condensing heat transfer correlation should follow. The Uchida heat transfer correlation (data) should be used for MSLB accidents while in the condensing mode. A natural convection heat transfer coefficient should be used at all other times when not in the condensing heat trans-fer mode for both LOCAs and MSLB accidents. The application of these correlations should be as follows:
(1) Condensing heat transfer (T -T) q/A = hcond s
y where q/A = the surface heat flux h
= the condensing heat transfer coefficient cond T
= the steam saturation (dew point) temperature s
T,
= surface temperature of the heat sink 1730 260
2 (2) Convective heat transfer (T -T) q/A
=h c
v w
where h
= convective heat transfer coefficient c
T
= the bulk vapor temperature.
y All other parameters are the same as for the condensing mode.
b.
Heat sink condensate treatment a
When the containment atmosphere is at or below the saturation temperature, all condensate formed on the heat sinks should be transferred directly to the sump. M.an the at. : sphere is r
superheated a maximum of 8% of the condensate may be assumed to remain in the vajor region.
The condensed mass should be calculated as folicws:
1 N
= X q / (h -h )
~~
cond y g mass condensation rate where M
=
cond X
= mass condensation fraction (0.92) q
= surface heat transfer rate h
= enthalpy of the superheated steam y
h
= enthalphy of the liquid condensate entering g
the sump region (i.e., average enthalpy of the heat sink condensate boundary layer).
1730 261 1
3 c.
Heat sink surface area The surface area of the heat sinks should correspond to that used for the containment design pressure evaluation.
d.
Single active failure evaluation Single active failures should be evaluated for those containment safety systems and components relied upon to limit the containment This evaluation temperature / pressure response to a LOCA or MSLB accident.
e de, but not necessarily be limited to, the loss or should inc availability of offsite power (whichever is worse), diesel generator failure wnen loss of offsite power is evaluated, and loss of containment heat removal systems (either partial or :otal).
- e. Containment heat removai system actuation 1
The time deterinined at wnicn active containment heat removal systbs become effective should incluce consideration of actuation M
sensors and setpoints, actuation delay time, and system delay time (i.e., time required to come into coeration).
Identification of mest severe environment f.
The wcrst case for environmental qualification shculd be selected ation at elevated temperatures as well as the considering time c In particular, consider the spectrum of maximum temperature.
break-si:es analyzed and singia failures evaluated.
1730 262 1
4 2.
Acceptable methodology for Safety Related Component Thermal Analysis Component thermal analyses may be performed to justify environ-mental qualification test conditions which are found to be less than those calculated during the containment environmental response calculation.
The heat transfer rate to components should be calculated as follows:
~
a.
Condensing heat transfer rate q/A = h (T 17) cond s
w where q/A = component surface heat flux
~
h
= condensing heat transfer coe/ficient cond
= the larger of 4x Tagami Correlation or ax Uchida Correlation T
= saturation temperature (dew poinc).
3 T,= component surface temperature b.
Convective heat transfer A convective heat transfer coefficient should be used wnen the condensing heat flux is calculated to be less than the convective 1 730 263
g 5
heat flux. During the blowdowr. period, a forced convection heat transfer correic.icn should be used.
For example:
NU = C (Re)"
where Nu = Nusselt Number Re = Reynolds Number C,n = empirical constants dependent en geometry and Reynolds f.unber The velocity used in the evaluation of Reynolds number may be cetermined as folicws:
V = 25 "BD V CONT -
where V
= velocity in ft/sec 7
M
= the blowdown rate in Ibs/hr BD V
3 CONT = containment volume in ft After the blowdown has ceased or reduced to a negligibly low value, a natural c::nvection heat transfer correlation is acceptable.
However, use of a natural convection heat transfer coefficient must be fully justified whenever used.
1730 264
APPENDIX B 1
IEEE itd. 323-1974 Qualification Profiles m
for B'lR and Ice Condenser Containnents IEEE Std. 323-19 24 hr 10 sec 3 hr 6,hr l
350 340,-
I t
T 300 f
{
Decay rate can be E
varied between the M
{
required end points.
P t
t F 250 3
t
\\
U N
No Staff s
requi rement f
s N
for rise time 200_
or decay rate f Qualification pressure for the first should be equal to or s
< f, greater than 110% of N,
N.
'f, calculated Dwell at peak is
~
suggested to be ten minutes f
150.(
Rate of decrease N
~
and duration should u
be identified on a O
BWR Containments case by case basis af ter 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
Ice Condenser Cnntainments Ln Time (asindicated)
1 APPENDIX C Sample Calculation a Type fiethodology for Radiation Dose 1730 266
T.
2
. The staff has estimated the accident radiation environment to be used for qualification of Class IE ecuipment for a design basis LOCA.
Beta and gamma dose rates and integrated doses have been calculated using models and assumptions consistent with that of Regulatory Guide 1.89.
This analysis is conservative, but does not ignore important time-dependent phenomena related to the action of ESF's and natural phenomena such as plateout, as done in previous staff analyses.
Doses were calculated for points within the containment atmosphere, at the containment surface (taking plated-out activity into account),
and near the sump water. Thirty day integrated doses for these points are shown below and canpared with comparable values from IEEE-323 (1974) for illustrative purposes.
THIRTY DAY INTEGRATED DOSES LOCATION INTEGRATED COSE, (RAD)
Beta Gamma Staff IEEE-323 Staff IEEE-323 8
7 7
1.4 x 10 5.5 x 10 (PWR)
Containment Atmosphere 1.3 x 10 7
2.6 x 10 (SWR) 7 6
Containment Surface 8.3 x 10 7.0 x 10 7
6 3.96 x 10 Near Sump Water 6.5 x 10
- Not Specified This report presents estimated dose rates for various times, for a represent-ative plant to illustrate the intended application of the staff recenmended model. Methods for suitable modification of the results oresented herein are also described to acccunt for changes in power level, containment volume or other appropriate features, to determine the recuired qualification levels for Class IE equipment at facilities significantly different frem the one analyzed herein.
7
3 APPLICABILITY OF SAND 76-0740, " RADIATION SIGNATURE FOL-LOWING THE HYPOTHESIZED LOCA," IN THE LICENSING PROCESS The subject report includes analyses of the radiation environment associated with the conditions set forth in Position C.2 of Regulatory Guide 1.89.
As noted in the text of that report (cf, Table 1.1, for example), those analyses are based upon calculational assumptions which are not consistent (are overly conservative) with respect to staff recommended practices. As such, the results in that report snould not be directly applied.
Certain of the information in SAND 76-0740 does not depend on a specific analysis of time-dependent transfer phenomena. Thus, the following ficures are acceptable for use:
2.3.4 and 3.3.4 2.4.1 and 3.3.1 (for energy of activity in coolant) 2.4.3 and 3.3.3 (but only with regard to energy dependence of iodine with time; the plate-out assump-tion of 25% should not be used) 3.4.1 and 3.4.3 The data in Appendices A-D ara acceptable. However, in establishing the radiation environment for specific equipment, this information must be adapted to take into account time-dependent phenomena (for example, it need not be assumed that the entire 50% of the halogen inventory is uni-formly distributed within the primary containment at t=0; a time-dependent buildup based on rate of removal of iodine from the containment atmosphere by sprays is acceptable).
1730 268
/
4 STAFF ANALYSES A.
General Summary of the Scenario The accident considered in this report for deternining the radi-ation environment for qualification of safety-related ecuipment is a design basis LOCA. The following is a description of the events that are postulated to occur for this accident.
At the time t=0, the pipe break occurs and results in rapid blowdown of the RCS.
Blowdown of the RCS would end approximately 20 to 40 seconds after the break. Flashing and escape of the RCS coolant during blowdown removes heat rapidly from the primary system and causes the fuel rod cladding temperature to drop. Consecuently, few fuel rods are expected to fail during the blowdcwn period.
Following t.Me end of bicwdown the fuel reds are uncovered and the stored heat in the fuel and the decay heat are transferred to the cladding causing the cladding temperature to rise.
Scme fuel rods may experience cladding failure during this period. The ECCS refills the lower reactor vessel and then refloods the core region within 100 to 300 seconds, causing cladding temperature turnaround.
Calculations using the RELAP-EM (Evaluation Model) program which uses the conservative assumptions given in Appendix X to 10 CFR Part 50 predict that the peak cladding temperature attained by the hottest fuel rod will be less than 2200*F. Based on the pre-dicted distribution of cladding temperature throughout the core, it is estimated that between 20% and 80% of the fuel rods could experience cladding failure for a PWR with a lesser fraction for a BWR.
1730 269 9
5 Ca'culations performed using the RELAP-BE (Best Estimate) procram indicated much Icwer claading temperatures than RELAP-EM. Based on the RELAP-BE predictions, the number of fuel rod claddino failures is estimated to be less than 10*..
Table 1 shows the The expected noble gases and iodine gap activity inventory.
source tems in Regulatory Guides 1.3, 1.4, 1.7 and 1.25 are shown for comparison.
During the initial blowdown only the radioactive material contained in the RCS coolant from steady-state operation would be released During reflood/ refill when fuel rod cladding to the containment.
failure may occur, the noble gases would be transported out of the primary system by steam flow and would become airborne within the primary containment of a PWR (or within the drywell of a SWR).
Some fraction of the iodines and less volatile fission products that are released as a result of fuel rod failure will also be transported out of the primary system by the steam flow and beccme airborne and seme fraction will remain in solution in the RCS/ECCS/
The sump water or deposit on surfaces within the primary system.
amount which becomes airborne outside the primary system would be strongly dependent on the time of fuel, red failure and the transport phencmenon for each species within the primary system.
a Following release from the. primary system the fission products For a PWR containment, would distribute within the containment.
the released airborne activity would rapidly disperse and beccme For a SWR, uniformly distributed within the primary containment.
Fol-the released activity would be airborne within the 'drywell.
Icwing initial release to the containment atmosphere the action of natural convection currents and ESF equipment, such as cooling fans, will cause time-dependent redistribution of the activity Natural removal processes such as within the containment.
deposition on containment surfaces and washout from the con-1730 270
6dinment atmospnere Dy action of sprays Woulo recuCe the air-f~
borne activity concentration and would redistribute the activity to internal surfaces and to the containment sump water.
During the same period of' time, leakage of radioactivity from tae containment to the atmosphere could take place. This would be processed to some extent, by ESF filters, causing a buildup of activity on these filters. There could be some deposition and plate-out of radioactivity (iodine and daughters of noble gases) on surfaces of ductwork or on the walls of secondary containment.
During the longer tem, contaminated primary coolant would be cir-culated through pipes outside of containment (PWR-RHR mode). The staff usually assumes a failure of a seal in the ECCS eouipment, such that significant quantities of coolant leak into these com-partments outside of containment. The leaked fluid is either retained in a sealed rocm or transported to the radwaste system.
Scme portion of this leaked fluid is volatilized and also trans-ported in the air of these compartments. These sources quid be processed to some extent by ESF filters.
B.
Basic Assumotions Used 3 the Analysis Gamma and beta doses and rates were deter-nined for three types of radioactive source distributions:
isotopes suspended in the con-tainment at:nosphere; plated-out on containment surfaces; in solu-tion or mixed in the containment sump water. Thus, a given piece of equipment may receive a dose contribution from any or all of these sources. The amount of dose contributed by each of these sources is deter nined by the location of the ecuipment, the time-dependent and location-dependent distribution of the source, and effects of shielding.
1730 271
Previous guidance issued by the staff was largely general in nature.
7 Recognizing "that implementation of this guidance requires a number of assumptions to be made regarding the time-dependent behavior of material within and outside of contairment, the staff, in the present report, has perfor ned an analysis of the radiation environment that might be associated with the source term of position C.2 of Regulatory Guide 1.89, using assumptions and methods which were intended to be consistent with other elements of staff practices in analyzing the radiological consecuences of a design basis LOCA. This is described below. An attempt has been made td highlight those assumptions which the staff believe are appropriate for general use.
C.
Analysis of the Concentration of Fission Products in Air This section discusses the physical model used to describe the P'4R containment and to determine the time-dependent and location-dependent distribution of noble gases and iodines airborne within the containment atmosphere and plated-out on containment surfaces.
The staff has developed a computer program (TACT), that is used to model the time-dependent behavior of iodine and noble gases within a nuclear power plant. Although the TACT code is used routinely by the staff for the calculation of the offsite radiological consequences of a LOCA, it provides an acceptable method for modeling the transfer of activity from one contaircent region to another and in modeling the reduction of activity due to the action of ESFs. Another staff code, SPIRT, is used to estimate the removal of elemental iodine by plate-out and sprays, needed input to TACT. These codes were used to develop the estimates described below.
1730 272 e
8 6
3 The containment freb volume was taken as 2.52 x 10 ft. Of this 6
3 volume 74". or 1.86 x 10 ft is directly covered by the con-5 3
tainment sprays. 6.6 x 10 ft of the containment free volume is un-sprayed which includes regions within the main containment room near the containment dome and compartments below the operating floor level.
Good mixing between the sprayed and unsprayed regions is assured due to action of natural convection currents and ESF fans. The ESF fans have a design flow rate of 220,000 cfm in the post-LOCA environment.
Since good mixing between all major unsprayed regions and compartments and the main sprayed region will occur, the containment was modeled with TACT nodes. Air exchange between the sprayed and unsprayed region was taken as one-half of the design flow rate of ESF fans plus the effect of natural convection.
The containmcat spray system consists of two equal capacity trains, each designed to inject 3000 gpm of boric acid solution into the con-tainment per train. Trace levels of hydrazine are added to enhance 1730 273 9
~
9 the removal of iodine. The spray removal rate constant (lambda) was calculated using the staff's SPIRT program, conservatively assuming only one spray train operates and an elemental iodine instantaneous partition coefficient (H) of 5000.
The calculated value of the ele-
-1 mental iodine spray removal constant was 27.2 he which represents an elemental iodine residence half-life in the sprayed region of approximately 1.5 minutes. Plate-out of iodine on contaimnent inter-nal surfaces was modeled as a first order rate renoval process and best estimates for model parameters were assumed.
Based on a total 5
2 surface area within containment of approximately 5.0 x 10 ft the calculated value for the overall elenental iodine plate-out constant
-1 was 1.23 hr In computing the radiological consequences at the ER and LPZ, the staff usually assumes a release of 100% of the noble gases and 25%
of the halogens is available for leakage from the contaim,ent.
Recognizing that it would take some time before a release of this magnitude' could occLe even assuming degraded ECCS operation, the staff has also assumed for purposes of estinatino off-site dose consequences that the source is uniformly distributed a.7d that containment sprays activate at the time the large source is available for release (both of which would also take time to occur). Also implicit in the 25t release of iodines is the assumption that 50% of a 50% release of iodine from the fuel is plated-out in a very short period of time.
g 1730 274
39 The staff usually limits credit for elemental iodine spray renoval tonomorethanA=10hr
, for an assumed release of 25" of the halogens to compensate for the artificial assumption of instantaneous pl ateout.
If a release of 50% were assumed (as is implied by Regulatory Guide 1.7 and TID-14844) the actual, conservatively calculated spray lambdas vould be appropriate.
In any event, removal of elenental iodine from the containment atmosphere by spray and plate-out is assumed to cease when the concentration in the sprayed region is reduced by a factor of 200 (when the initial concentration of iodine in the containment is calculated assuming 50% of the core inventory of iodines is initially airborne). This reduction factor is obtained by doubling the reduction factor utilized in the LCCA dose analysis.
The intent is to achieve an equilibrium airborne iodine concentration that is consistent with the LOCA analysis.
Since the initial (t=0) concentration is assumed to be twice that of the LCCA analysis (50%
vs. 25%) the reduction factor has been doubled.
The staff (see Regulatory Guides 1.3 and 1.4) assumes that other forms of iodine are present, or will be forn.ed in a design basis LOCA.
Specifically, it is assumed that 2.5% of the core inventory of iodine released is associated with airborne particulate material and 2% of the core inventory of iodine released forms organic comp 7unds.
While these values would not be obtained until several hours after the LOCA, it is the staff assumption that the aforenentioned composition is present at t=0.
-1 A removal rate constant of 0.43 hr was calculated for particu-late iodine. The organic iodine concentration in the containment atmosphere was assumed to be unaffected by containment sprays or pl a te-out.
r 1730 273
11 The action of sprays would not commence at t=0 (e.g., sone time would elapse"between the' onset of the LCCA and the delivery of spray solution to the spray nozzles).
Similarly, as discussed above, the assumed large source would not be immediately released.
from the fuel. Lastly, some time would transpire before any air-borne iodine would be distributed throughout containment.
The assumption of a large release, uniformly distributed in containment (or in the sump water as will be discussed belcw) is a convenient simplification for purposes of the dose assessment in a PWR, but is unrealistic in terms of specifying the time-dependent radiation en-vironment. However, accurate coupling of the various time sequences is beyc9d the scope of this effort.
The staff calculated values of noble gas and airborne iodine activ-ity in the containment as a function of time following the LCCA are presented in Table 2.
D.
Analysis of the Concentration of Fission Products on Surfaces It should be noted that the air dose model assumed only one cut of two scray trains and one out of two ventilation system trains were operable.
If, as is expected, both trains of both systems were operable, spray washout would progress more rapidly in the sprayed regions and the " equilibrium" of concentrations between sprayed and unsprayed regions would be reached more quickly. The result would be lower dose rates due to activity on surfaces or suspended in the air in sprayed regions, and in unsprayed regions during the early phases of the accident.
I730 276
12 It has occasionally been suggested that the plate-out source used in estimating the radiation environment for equipment should assume that 25% of the halogens are instantaneously plated-out on containment and equipment surfaces. This assumption is clearly inconsistent with the time-dependent model used to characterize the concentration of iodines in the air (or, as will ce discussed, the assumption that 50% of the halogens are instantaneously distributed in the sump fluid).
It is the staff's view that the estimates should be mechanistically consi stent. A large margin of conservatism already exists by vir-tue of the assumed large source tem.
In any event, the subsequent removal of deposited material by wash-off (by sprays or condensate flow) may be important.
Ignoring this factor (as was done for this short-tem effort) introduces conservati sm. A mechanistically consistent analysis should involve calculations of doses due to surface sources as well as for airborne sources. Current staff guidelines do not include an acceptable method for estimating this contribution to the radiatfor.
environment. Absent such methods it has been assumed that all plated-out material is retained. Table 3 shows the values evaluated by the staff for the iodine activity buildup on the plate-out surfaces of the containment.
E.
Analysis of the Concentration of Fission Products in the Sumo Regulatory Guide 1.7 (Table 1) suggests that it be assumed that 50%
of the halogens and 1% of the solids present in the core are inti-mately mixed with the coolant water. These values stem directly from TID-14844 (and we presume that the 1% solids refer to fission products other than halogens and noble gases). No specification of the time-dependencies for this source are given.
However, for a 1730 277
13 PWR with containment sprays, the elemental iodine (constituting about 95% of available iodine) is rapidly washed-out of the contain-ment atmosphere and transported to the containment sump (over 90% in less than 15 minutes is a typical result). Table 4 presents an estimate of buildup of iodine in the sump fluid. There is little difference in the estimated integrated dose from the sump water between these values and values resulting from an assumed instantaneous release of 50% of the halogens into the sump.
The inclusion of solid fission products in the sump source seems to be an artifact from the source of TID-14844. While it may have applicability to the estimates of hydrogen production per Regulatory Guide 1.7, its applicability to radiation dose estimates has not been fully resolved.
Pending this resolution it should ce assumed that the sump fluid contains 1% of the solid fission products and that the solid fission products are released and uniformly distributed in the sump fluid at t=0.
1730 278 O
O e
g-14 ESTIMATES OF THE RADIATION ENVIRONMENT Previous staff estimates, as noted earlier, did not take into account the important time and spatially dependent phenomena.
The calculated radiation environment was generally taken as a a point on a surface or in the center of contaimnent.
The activities within the containment regions were used as input to calculate the beta and gamma dose rates and integrated doses.
One typical location was assumed to be a point located in the center of the main containment region. A second location was assumed to be a point on a containment inner surface. A third location would be that adjacent to the sump water. Doses for representative points outside containment were taken from Reference 1 and are also listed for completeness.
The gamma transport calculations were performed in cylindrical gecmetry.
Containment internal geonetry was not modeled as this was considered to involve a degree of complexity beyond the scope of the present work. The calculations of both References 2 and 3 indicate that the specific internal shielding and structure would be expected to reduce the gamma doses and dose rates by factors of two or more, depending upon the specific location and gecmetry. The beta doses were calculated using the infinite medium approximation. Because of the short range of the betas, this was shown in Reference 4 to result in only
.small error. The beta doses are not expected to be significantly reduced by the presence of containment internal structures.
Finally, the doses were multiplied by a correc^f on factor of 1.'
as suggested by Reference 4 to account for the neglect of the decay chains with subsequent growing-in of acditional daughter products.
1730 279 f
15 A.* Containment Atmoschere Doses And Inteorated Dose The beta and gamma dose rates and integrated doses for a point detector on the containment centerline exposed to the airborne activity within the contaimnent atnosphere was calculated.
The containment was modeled as an air filled cylinder whose height equaled the diameter. Containment internal structure and shielding were neglected. The gamma dose rate contribution for the plateout iodine on containment surfaces to the de,tector was also modeled and included as a contributor. The gamma dose rates and integrated doses are shown in Table 5 while the beta dose rates and integrated doses are shown in Table 6.
The in-creased pressure effects in a post-LOCA contaf ranent have not been considered. This results in a snall conservatism in the calculated dose.
B.
Surface Doses and Dose Rates The beta and gamma dose rates and integrated doses were computed in the paint where iodine fission products were presumed plated-out. The contaimnent surface was assumed to be composed of paint with a thickness of 10 mils (0.0254 cm) with an average density 3
of 2 gms/cm.
Subsequent removal of plated-out activity with time is expected to be a complex phenomenon dependent upon such conditions as whether the surface is exposed to the sprays and whether moisture con-densation and runoff can be expected to remove surface activity.
l730 280
16 Half of the beta energy from plated-out iodine is directed toward the painted surfac'e. The airborne contribution was added to the plate-
~
out contribution and all the betas directed toward the paint surface were assumed absorbed in the paint. This is conservative since the maximum range for betas is greater than the paint thickness. Hence, this assumption may overestimate the beta dose for a paint surface, for example, but may be appropriate for a much thicker cable insulation layer. The airborne contribution was taken to be one half the dose rate from an infinite cloud.
The gamma dose rate at the plated-out surface exposed to airborne activity Was calculatJd to be one half of the dose rate for a detector at the contaimnent centerline. Although half of the gamma energy from plated-out iodine is also directed toward the painted surface, the paint surface 1: calculated to be relatively transparent to gammas with only about 1% of the plated-oct gammas absorbed by the paint and the contribution is considered negligible.
The gamma dose rates and integrated doses are therefore half of the center point values for an airborne detector computed previously above and the gamma dose rates are not sionif'cantly affected by removal of plated-out activity with time.
The beta dose rates and integrated doses for "well-washed" and
" unwashed" surfaces, respect',vely, are shown in Table 8.
1730 281 6
0
C.
Dose Near Sumo Water 17 e
The activity in the sump water was assumed to vary with time, and was assumed initially to be free of any iodine fission products.
Ultimately, however, essentially all the iodine released appears in the sump water. Table a shows the iodine activity in the sump as a function of time. Note that the maximum is reached in about 0.2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> with radioactive decay reducing the activity afterwards.
The beta and gamma dose rates and integrated doses were computed for a detector located at the surface of a large pool of sump water contaminated by iodine and solid fission products. 44,200 cubic feet of water was assumed to cover the bottom of the con-ta i.nment. The containment geometry was simplified to assume a uniform depth of water of about 2.5 feet, and the dose rates *ere calculated at the sump water surface. The actual dose contribution for a detector located at the sump surface would cane about ecually from the activity in the sump and from the airborne activity.
The gamma dose rate and integrated dose from the sump water source only are shown in Table 7.
1 0 282 mu m
18
~
D.
Ecuf oment Outside Containment Although not specifically calculated in this study, several values of dose rates and doses at points outside of containment were taken from Reference 1 for completeness. The methods used in arriving at these results are acceptable for plaat specific determination.
The gamma dose rates and integrated doses at a point outside of containment are shown in Table 9, taken from Reference 1.
The containment source was assumed to be a Regulatory Guide 1.4 source (with a power level of 4000 MLtl and was shielded by 3 feet of concrete. The dose rates at the beginning of recir-culation near a pipe containing water contaminated by iodine fission products was also calculated in Reference 1 and the dose rates are shown in Table 10.
30 283
-ep O
O e
e 9
Comoarison of a pWR and a BWR Due to time constraints it was not possible to develop a detailed model for a BWR equihalent to the PWR model presented in this report. Doses to equip-ment inside a BWR containment would not be expected to differ greatly from the doses calculated for PWR equipment. However, the compartmented design of BWR containments, and the fact that most BWRs generally do not have con-tainment sprays designed for rapid iodine removal, will result in some dif-
.ferences in equipment doses. Several of the models and assumptions used in the PWR analysis would not be appropriate for an equivalent analysis for a BWR. Specifically the assumption of an initially uniformly distributed air-borne concentration of activity throughout the containment is not an appropriate assumption for a BWR containment. Following the blowdown portion of the LOCA the air exchange rates between the drywell region and the remainder of the containment free volume will be relatively small.
(In this discussion we are primarily considering a BWR with a MARK III type containment structure.)
Since any major releases of activity would be initially into the drywell and would occur following the blowdown period, only relatively slow transport would occur to the main containment volume. Consequently an appropriate model for a BWR containment should consider that all (or most) of the acti-hity is initially released into the drywell region. Furthemore, it is impor-tant to correctly estimate the atmos;iheric mixing rates between the drywell and the main containment regions (including sprayed and unsprayed regions) in order to adequately estimate the time-dependent and location-dependent distribution of activity. This should include an estimation of the flow between the drywell and the main containment which by passes the suporession pool. This suggests a relatihely detailed multi mode containment model if overly conservatihe estimates of the radiaticn environment are to te avoided.
Remohal of iodines from the main containment region and from the drywell by the operation of ESF systems such as containment sprays should be modeled in a manner similiar to that utilized in calculating off-site doses (i.e. single f ailure etc) time-dependent deposition of iodines on surfaces by natural processes should be evaluated using mechanistic models and best estimates for model parameters, this w ll require a relatively detailed evaluation of potential de-i position surfaces within the main containment and drywell. Capture of iodines in the suppression pool may be important and should be evaluated.
1730 284
~~
LIST DF TABLES 20 PAGE NO.
TABLE NO.
1.
Comparison of Source Terns 2.
PWR Activity Distribution Within Con-tainment vs Time - Base Case 3.
Plate-Out Surface Activity and Gamma Dose Rate Contribution to Dose at Containment Centerline vs Tine -
Base Case 4.
Iodine ctivity in Containment Sump vs Time - Base Case 5.
Total' Gamma Dose Rates and Integrated Doses in the Containment Air - Base Case 6.
Beta Dose Rates and Integrated Doses in the Containment Air vs Time -
Base Case 7.
Beta Particle Dose Rates and Integrated Doses to Paint on Containment Wall vs Time - Base Case-8.
Containment Sump Gamma Dose Rates and Integrated Doses at the Sump Surface vs Time - Base Case 9.
Dose Rates and Integrated Doses Dut-side Shielded Contaimnent 10.
Dose Rates at Beginning of Recirculation Near Pipe B-1 Energy Group Structure and Dose Conver-sion Factors B-2 Photon Energy Flux to Exposure Dose Rate Conversion Factors C-1 Dose Rase Calculation to a Point in the Center of Containment from the Plate-Out Source 1730 285
21 TABLE 1 SOURCE TERMS Activity Released From Fuel
(% of total core inventory) 1.) Source Term Based on TID-14844 Noble Gases Iodines Solids (Reg. Guides 1.3, 1.4) 100%
50 ;
0 2.) Source Term Based on R. G.
100%
50%
1%
1.7 and 1.89 Rev 0. (Base Case) 3.) Source Term Based on Conservative 10%(30% of kr-85) 10%
0%
Gap Release (Reg. Guide 1.25) 4.) Best Estimates of Total Activity Gap WASH-1400 3%
5%
NUREG/cr-0091*
1.27%
2.79%
- Calculated for stable and long-half-life isotopes.
1730 286 t
8
~
22 TABLE 2 PWR ACTIVITY DISTRIBUTION WITHIN CONTAINMENT VS. TIME - BASE CASE, Ci Ncble Elemental Organic Particulate Total Total Time (hri Gases Iodice Iodine Iodine Icdine Airhnena 0.0 1.31 + 9 4.37 + 8 9.15 + 6 1.14 + 7 4.58 + 8 1.77 + 9 0.3 1.19 + 9 4.17 + 8 9.07 + 6 1.13 + 7 4.37 + 8 1.63 + 9 0.50 7.36 + 8 3.56 + 6 7.98 + 6 8.58 + 6 2.01 + 7 7.56 + 8 0.'75 6.80 + 8 3.35
- 6 7.51 + 6 7.46 + 6 1.83 + 7 6.98 + 8 1.00 6.41 + 8 3.17
- 6 7.11 + 6 6.52 + 6 1.68 + 7 6.58 + 8 2.00 5.54 + 8 2.66 + 6 5.95 + 6 3.96 + 6 1.26 + 7 5.67 + 8 8.00 3.62 + 8 1.62 + 6 3.62 + 6 3.56 + 5 5.60 + 6 3.68 + 8 24.00 2.33 + 8 9.11 + 5 2.04 + 6 1.21 + 3 2.95 + 6 2.36 + 8 1.57 + 6 1.66 + 8 60.00 1.64 + 8 4.84 + 5 1.09 + 6 96.0 1.33 + 8 3.47 + 5 7.78 + 5 1.13 + 6 1.34 + 8 192.00 7.84 + 7 2.19 + 5 4.92 + 5 7.11 + 5 7.96 + 7 4.82 + 3 4.54 + 7 298.00 4.49 + 7 1.48 + 5 3.34 + 5 3.42 + 5 2.76 + 7 394.00 2.73 + 7 1.05 + 5 2.37 + 5 560.00 1.20 + 7 5.76 + 4 1.31 + 5 1.89 - 5 1.22 + 7 720.00 6.01 + 6 3.23 + 4 7.36 + 4.
1.C6 + 5 6.12 + 6 1730 287 O
23 TABLE 3 PLATEOUT SURFACE ACTIVITY IN THE CONTAINMENT VS TIME FOR THE BASE CASE Time Iodine Activity (hrs)
Deposited on Surfaces, Ci 0.0 0.0 O.03 1.57 + 7 0.07 2.96 + 7 0.14 3.92 + 7 0.20 4.23 + 7 0.40 0.50 4.23 + 7 0.75 3.98 + 7 1.00 3.77 + 7 2.00 3.15 + 7 8.00 1.92 + 7 24.00 1.08 + 7 60.60 5.76 + 6 96.00 4.13 + 6 192.00 2.61 + 6 1.77 + 6 298.00 394.00 1.25 + 6 560.00 6.91 + 5 720.00 3.90 + 5
24 TABLE 4 IODINE ACTIVITY IN CONTAINMENT SUMP VS TIME IODINE ACTIVITY IN CONTAINMENT SUMP, Ci Time (HRS)
Elemental Particulate
- 0.0 0
0 0
0 0.03 0
0 2.04 + 8 0.07 2.04 + 8 3.04 + 8 0.14 3.04 + 8 3.35 + 8 0.20 3.35 + 8 0.25 3.44 + 8 3.44.+ 8 0.50 3.34 + 8 1.39 + 6 3.35 + 8 0.75 3.15 + 8 1.93 + 6 3.17 + 8 1.00 2.98 ' 8 2.36 + 6 3.00 + 8 2.00 2.49 + 8 3.48 + 6 2.52 + 8 8.00 1.52 + 8 4.18 + 6 1.56 - 8 24.00 8.58 + 7 2.54 + 6 8.83 + 7 60.00 4.56 + 7 1.36 + 6 4.70 + 7 96.00 3.27 + 7 9.75 + 5 3.37 + 7 192.00 2.06 + 7 6.15 + 5 2.12 + 7 298.00 1.40 + 7 4.18 + 5 1.44 + 7 394.00 9.43 + 6 2.96 + 5 1.02 + 7 560.00 5.48 + 6 1.63 + 5 5.64 + 6 720.00 3.09 + 6 9.30 + 4 3.18 + 6
- Particulate Iodine Activity in the Containment Sump for timesless than 0.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> is small and when added to the Elemental Iodine Activity does not significantly affect the total magnitude of the Iodine Activity in the sump.
~
1730 289
25 TABLE 5 TOTAL GAMMA DOSE RATES AND INTEGRATED DOSES AT THE CONTAINMENT CENTER IN AIR VS TIME - BASE CASE UNWASHED Time (Hrs)
Gamma Dose Gamma Dose Total Gamma Total Rate From Rate in Air Oose Rate in Integrated Airborne From Plate-Air (R/Hr)
Gamma Dose (R/Hr)
Out Source in the (R/Hr)
Containment Air, R 0.0 4.92 + 6 1.56 = 4 4.92 + 6 0.03 4.43 + 6 5.59 + 4 4.49 + 6 2.06 + 5 0.50 1.33 + 6 1.44 + 5 1.47 + 6 1.18 + 6 0.75 1.16 + 6 1.33 + 5 1.29 + 6 1.55 + 6 1.00 1.05 + 6 1.23 + 5 1.17 + 6 1.82 + 6 2.00 7.7E + 5 9.44 + 4 8.69 + 5 2.80 + 6 8.00 2.37 + 5 4.14 + 4 2.78 + 5 6.0
+6 24.00 5.19 + 4 1.58 + 4 6.77 + 4 7.1
+6 60.00 1.70 + 4 6.36 + 3 2.34 + 4 9.2
+6 96.00 1.30 + 4 4.36 + 3 1.74 + 4 1.0
+7 1.03 + 4 1.15 + 7 192.C0 7.66 + 3 2.66 + 3 298.00 4.38 + 3 1.80 + 3 6.18 + 3 1.20
- 7 394.00 2.67 + 3 1.23 + 3 3.95 + 3 1.25 + 7 560.C0 1.14 + 3 7.04 _+ 2 1.54 + 3 1.30 + 7 720.C0 5.14 + 2 3.98 + 2 9.12 + 2 1.36 + 7 1730 290
e 26
[ABLE6 BETA DOSE RATES AND INTEGRATED 00SES AT THE CONTAINMENT CENTER V5. TIME IN AIR Time (Hr's)
Dose Rate in Integrated Dose in Containment Air Containment Air (R/HR)
(R) 2.373 + 7 0.0 1.951 + 7 8.89 + 5 s
0.03 5.856 + 6 3.55 + 6 0.25 4.198 + 6 4.93 + 6 0.5 3.671 + 6 6.0 + 6 0.75 1.0 3.369 + 6 7.13 + 6 2.0 2.758 + 6 1.03 + 7 1.538 + 6 2.21 + 7 8.0 7.068 + 5 4.1 + 7 24.0 3.919 + 5 6.1 + 7 60.0 3.117 + 5 7.2 + 7 96.0 192.0 1.871 + 5 g,g + 7 1.083 + 5 1.03 + 8 298.0 6.807 + 4 1.08
- 8 394.0 3.278 + 4 1,17 + 3 560.0 1.901 + 4 1.26 + 8 720.0 1730 291-I
27 TABLE 7 BETA BOSE RATES AND INTEGRATED DOSES FOR PAINT ON CONTAINMENT WALL - WASHED AND UNWASHED CASES Dose Rate Dose Rate Oose Dose Time Unwashed Washed Unwashed Washed (Hr)
(R/HR)
(R/HR)
(R)
(R) 0 1.19 + 7 1.19 + 7 0
0 0.03 1.01 + 7 9.76 + 6 4.99.+ 5 6.46 + 5 0.25 3.79 + 6 2.93 + 6 1.81 + 6 1.69 + 6 0.5 2.92 + 6 2.10 + 6 2.70 + 6 2.32 + 6 0.75 2.'60 + 6 1.84 + 6 3.65 + 9 3.0
+6 1.0 2.39 + 6 1.68 + 6 4.20 + 6 3.25 + 6 2.0 1.94 + 6 1.38 + 6 6.39 - 6 4.77 + 6 8.0 1.07 + 6 7.69 + 5 1.42 + 7 9.9
+6 24.0 5.05 + 5 3.53 + 5 2.55 + 7 1.77 + 7 60.0 2.60 + 5 1.96 + 5 3.90 + 7 2.73 + 7 96.0 1.96 + 5 1.56 + 5 4.6
+7 3.3
-7 192.0 1.16 + 5 9.36 + 4 6.0
+7 4.4
+7 298.0 6.90 + 4 5.42 + 4 7.0
+7 5.2
+7 394.0 4.45 + 4 3.40 + 4 7.6
+7 5.6
+7 560.0 2.22 + 4 1.64 + 4 8.2
+7 6.1
+7 720.0 1.28 + 4 9.51 + 3 8.29 + 7 6.33 + 7 1730 292
28 TABLE 8 CONTAINMENT SUMP GAMMA DOSE RATES AND INTEGRATED DOSES VS TtE Dose Rate Dose Rate at the at the Sump Surface Total Dese Sump Surface From 1%
Rate at the Total Integrated From Icdine Solids in Sump Surface Gamma Dose at the Time (Hrs)
II(MEV)
In Suma R/HR Sump, R/HR R/HR Sump Surface, R 0.0
.887 0.0 5.90 + 4 5.90 + 4
'O.03
.887 0:0 3.09 + 4 3.09 + 4 4.65 + 2 0.07
.886 1.18 + 5 0.14
.884 1.79 + 5 2.21 + A 2.01 + 5 1.23 + 4 0.20
.882.
1.94 + 5 0.25
.880 1.99 + 5 1.90 + 4 2.18 + 5 2.82 + 4 0.50
.873 1.83 + 5 1.59 + 4 1.99 + E 7.89 + 4 0.75
.866 1.71 + 5 1.00
.860 1.56 + 5 1.25 + 4 1.68 + 5 1.68 + 5 2.00
.839 1.19 + 5 1.01 + 4 1.29 + 5 3.00 + 5 8.00
.763 5.08 + 4 24.00
.569 1.61 + 4 4.99
- 3 2.11 + 4 1.15 + 6 60.00 401 6.04 + 3 96.00
.357 3.81 + 3 3.09 - 3 6.90 + 3 1.95 + 6 192.00
.332 2.20 + 3 298.00
.330 1.50 + 3 2.14 + 3 3.64 + 3 2.95 + 6 394.00
.330 1.06 + 3 560.00
.330 5.86 + 2 1.61 + 3 2.20 + 3 3.55
- 6 720.00
.330 3.30 + 2 1.42 + 3 1.75 + 3 3.96 + 6 1730 293
29 TABLE 9 00SE RATES OUTSIDE SHIELDED CONTAINMENT (3 feet Concrete Shield)
Time After Release, Hours Dose Rate, R/hr Intearated Dose, Rads 2
0 4.0 x 10 0
2 2
1 2.5 x 10 3.2 x 10 2
2 3
1.2 x 10 6.9 x 10 2
3 10 2.8 x 10 1.2 x 10 0
3 30 2.4 x 10 1.5 x 10 3
100 2.3 x 10-2 1.6 x 10 1730 294 O
G
30 TABLE 10 DOSE RATES AT BEGINNING OF RECIRCULATION NEAR PIPE CONTAINING IODINE FISSION PRODUCTS Distance Oose Rate, R/hr 5
4 inches 1.6 x 10 4
1 foot 5.3 x 10 4
3 feet 1.8 x 10 1730 295 O
4
31 LIST OF FIGURES FIGURE NO.
, A-1 Relative Airborne Activity vs Time for Sprayed and Unsprayed Containments A-2 Fractional Airborr.e Iodine Activity by Physicchemical Form Relative to the Total Initial Iodine Activity A-3 Elemental Iodine Distribution in the Containment vs Time - Spray Washout and Plate-Out AA Elemental Iodine Distribution in the Containment vs Time - Plate-Out Only 1730 296
32 APPENDIX 0 Effect of Sorays and Plateout on Activity Distribution Within Containment Figure A-1 shows a plot of the airborne activity within the containment for the period from 0 to 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> following the accident. The total activity
' at time t divided by the total airborne activity at time 0 is plotted for two cases.
In one case it was assumed that the containment sprays were not operating and in the second case operation of one containment spray'.-
train was assumed.
In both cases natural deposition of elemental iodine on surfaces was modeled. After approximately two hours the large majority of the iodines have been removed from the atmosphere, by the spray in the first case and by the slower natural deposition process in the second case.
Consequently the airborne activity in both cases is largely due to decay of the noble gases.
Figure A-2 shows plots of the fractional airborne activity (relative to the total iodine activity at time t=0) of the three physicchemical forms of iodine for both the sprayed and unsprayed cases.
Figures A-3 and A-4 show the time-dependent and location-dependent distribu-Plotted is tion of elemental iodine for.the sprayed and unsprayed cases.
the fraction of the total elemental iodine activity that is (1) in the sprayed containment regicn (2) in the unsprayed containment region, or (3) plated out on containment surfaces.
I730 297
1
~
33 For the case where no spray operation was assumed, greater than 90% of the remaining elemental iodine activity is predicted to have deposited on containment surfaces two hours following the accident. The peak iodine surface activity approaches 60% of the total initial elemental, iodine activity at about this time. For the sprayed case the peak surface activity is only about 10% of the total initial iodine activity due to the rapid removal of elemental iodine from the atmosphere by action of the sprays which limits the amount of iodine available for deposition on surfaces.
1730 298
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37 APPENDIX E-Descriotien of the Ecuivalent One Grouc Method In this section, the basis for the use of an equivalent one group method is established and the method is derived. A comparison with a twelve group method is shown and other results and conclusions presented.
A one group method pennits rapid evaluation in complex geometries and is easily applied and checked by hand calculations.
In addition, integral quantities such as average energy permit valuable insight into understanding what is occurring and can help identify incorrect results.
The photon flux at the center of a sphere can be written
$= B4 ( l-e-uR) u A power series expansion of the exponential term e "" yields
~
F I
$= SS R 1 - (1-uR + (uR)2,,,,)
y uR 2!
and neglecting all terms of order greater than one yields the approximaticn o= BS R (uR) = BS R y
y app uR indication that the photon energy distribution is weakly dependent upon gecmetry in air filled containments of this si::e. The accuracy of this approximation can be estimated by the departure fecm unity of the ratio:
o/t app. = (1-e -uR), 3,,-0.206 = 0.904 uR where u= 0.0707 cm-I for air at 1 Mev and 1730 302 R= 2574 c:n
I 38 which supports the assumption of spectral insensitivity for the photon 6
3 flux for air filled volumes of 2.522 (10 ) ft or less.
Similarly, the photon flux for a point on the surface of sphere can be written:
-2uR 4 = BSv 1
+e 22 FJ 2aR j
or, keeping the first three tenns of the Taylor series expression for the expatential yields:
$ = ESv 2
showing that the flux on the surface of the sphere is about 1/2 the flux at the center, which is verified by the use of the exact expressions as shown below.
Sencnmark calculations were performed using a twelve energy group repre-sentation. The energy groups and widths are shown in Table B.1-1.
Note that each energy group was treated as a mono-energetic source and that the geometric model was then applied to the source. This method does not require coupling between the twelve energy groups. The resulting
^twelve dose rates were then sumed to provide the total dose rate frem the airborne source at that point in time.
The photons per second in each of the energy groups was obtained at a representative TACT time step since TACT provides curies for each isotope at each time step. Using the photon disintegration distributions associated 1730 303
39 with a specific isotope given in Reference 5, photons per second were assigned to each energy group in accordance with the relative concentrations of their emitters at the point in time associated with the time step.
The energy spectrum changes with time because the isotopes have different decay constants and because sprays remove halogens but not noble gases.
After Reference 6, the airborne immersion dose was calculated for each energy group at each time step as follows:
y Y
h
<fc>
j Y
N c -+
u, f
V J
At any point, P, located within a cylindrical volume source emitting Oy gamas per cubic centimeter each second, the energy flux may be expressed as:
2 b ("s ), 9 p )+G(ah,u')]
h
- E*
3 s
s2 s
j=1 where
= c [ l + 0.24062f2 + 0.97062f(2.6337 - f )o 5 ]o 5 2
p 1730 304
I 40 and o = c [ l + 0.24062f2 - 0.97062f(2.6337 - f )o s jo s 2
The flux to dose conversion f actors are shown in Table B.1-2.
The calculations were compared with the spherical model for both points at the center and on the surface of the sphere.
The accuracy of the equivalent one group model with respect to the twelve g-oup representation was demonstrated using spherical gecmetry.
6 The twelve group model gave a dose rate of 3.52(10 )R/Hr whereas the 6
equivalent one group model gave 3.77(10 )R/Hr.
Since the upper containment was configured as a right circular cylinder with H/D = 1.0, it is to be expected that agreement with a spherical representation should be good, as shown in the following figures.
f j'
\\
4 Xb f5 I A 1
t j
Dose Rates: R/Hr 6
6 P): 3.824 (10 )
P: 3.923 (10 )
4 6
6 P: 2.466 (10 )
p:
1.903 (10 )
2 5
6 6
1730 3%
P: 2.227 (10 )
p:
1.903 (10 )
3 5
41 and P, are within three percent.
Note that the center dose rates, i.e., Pj 4
Similarly, the ratio of the surface to the center dose rates of the sphere is almost exactly 1/2 as previously derived. The ratio of P to P is 1.3 2
5 and the ratio of P to P is 1.17, which is good agreement considering that 3
S the generalized cylindrical expression used may be in error by as much as 15%. As a result, except for the example given above, all the dose rates for uniformly distributed airborne sources were calculated using the spherical model.
Subcompartment dose rates for airborne sources were calculated assuming an equivalent volume spherical mcdel developed which were used to cbtain subccmpartment doses as a function of subccmpartment volume. The scurce concentration used to calculate the subccmpartment doses were those calculated for the unsprayed region in the TACT mcdel.
The dose rates in the main containment region were calculated using the source concentrations calculated for the sprayed region. The equivalent one group model was derived as fo11cws:
D(E) = K(E)c(E) = K(E) B S(E)E (1-e-u(E) R) u(E) V Define:
R = /K(E) E S(E) dE
~
/ E S(E) cE Similarly:
IK(E)S(E)EdE g,
1730 306
/S(E)dE and { =
42 and E=
/E S(E) dE IS(E) cE v
)
IS(E) dE v(7 S
=
cm - sec V
where u and B are evaluated a E.
With these definitions it follows that
' the total dose rate (0) at a given point in time is:
0 = R B(E)SvEr (1-e-u(E)R)
.u(E) for the center of a sphere. The same average parameters can be used in other gecmetrical representatives.
For containment volumes which can be represented by equivalent spheres, the dose rate (0) can be raticed as follows:
2 2
2 = (P/R )] f(Pjg )
0 /0 3
where P is the reactor thennal power. This follows frem expressing 0 = eBSuR (1-e-uR) uR V approximately as 0 = KBS R (uR)
F3T v since S E S/V and V is the containment volume y
0=GS 2
2 2 - S/R - P/R (4/3 x) R
43
~
TABLE B.1-1 ENERGY GROUP STRUCTURE AND DOSE CONVERSICN FACTORS K (E) 9 2
Group Ei(MeV)
(R/hr per MeV/cm sec) gg 1
0.30 2.03-6 0.32 1.94-6 0.40 2
0.63 3
1.10 1.81-6 0.46 4
1.55 1.71-6 0.45 5
1.99 1.56-6 0.42 6
2.38 1.49-6 0.38 7
2.75 1.43-6 0.44 8
3.25 1.37-6 0.48 9
3.70 1.31-6 0.49 10 4.22 1.26-6 0.50 11 4.70 1.23-6 0.52
'12 5.25 1.19-6 0.56 1730 308
,~
44 TABLE B.1-2 PHOTON ENERGY Fl.UX TO EXPOSURE DOSE RATE CONVERSION FACTOR E
k(E)
E k(E) 2 MeV R/hr per MeV/cm sec MeV R/hr per MeV/cm sec 0.5 1.96-06 5.0 1.20-06 0.6 1.94 5.2 1.19 0.7 1.92 5.4 1.18 0.8 1.90 5.6
-1.16 0.9 1.87 5.8 1.15 1.0 1.84-06 6.0 1.14-06 1.2 1.78 6.2 1.13 1.4 1.73 6.4 1.12 1.6 1.67 6.6 1.12 1.8 1.62 6.8 1.11 2.0 1.56-06 7.0 1.10-06 2.2 1.53 7.2 1.09 2.4 1.49 7.4 1.09 2.6 1.46 7.6 1.08 2.8 1.42 7.8 1.08 3.0 1.39-06 8.0 1.07-06 3.2 1.37 8.2 1.07 3.4 1.35 8.4 1.06 3.6 1.32 8.6 1.06 3.8 1.30
- 8. 0 1.05 4.0 1.28-06 9.0 1.05-06 4.2 1.26 9.2 1.05 4.4 1.25 9.4 1.04 4.6 1.23 9.6 1.04 4.8 1.22 9.8 1.03 5.0 1.20-06 10.0 1.03-05 1730 309 O
. =.
e 45 APPENDIX F: CALCULATION OF PLATE 0VT GAMMA DOSE RATE IN THE AIR The dose rate contribution from the plateout elemental fodine was approxi-mated by assuming the calculated activity is plated out on a right circular cylinder having the dimensions of a particular containment (in this case
~
ERIE). The radius of the right circular cylinder used was 73.8 ft and the
' height used was 147.5 ft.
The activity is assumed uniformly distributed over all surfaces so the surface source density is easily calculated by dividing the photon spectra (y/sec) by the plateout area.
The area of a cylindrical shell is calculated as A3 = 25RH which yields a 4
2 surface area of 6.84 x 10 ft when using the dimensions above. The area of the containment dome and of the lower floor areas was approximated by two disks. The area of each disk was calculated by the circle fomula 2
4 2
A = sR and yields a value of 1.71 x 10 ft for the given dimensions.
The dose rate to a receptor point at the center of containment frcm a disk source is calculated using the equation:
SA R2
$ = y in (1 + p) where 4
2 6
SA = y/(sec-ft )
R = radius of the disc (feet)
Z = perpendicular distance 3
from the disc to the receptor point P on the disc centerline i
1730 310
i 46
~
Forthiscalculationf=1sotheequationfororeducesto e=
in (1 + 1) or 5 x 0.1733. The dose rate is calculated using the 4
equation Og = K(E) x E x S where S =.1733 S. This would account for the A
dose rate from only one disk; however, since it is necessary to consider the dose rate from the floor as well as the dome, the dose rate equation
' was multiplied by 2 yielding:
KIL)
DR = 2 x.1733 SA or the dose rate contributicn from the two disks (dome + ficors) can be obtained using the equatien 5
X(.E) E =.3466
<(!) E DR = 0.3466 54 Adisk where: S = the number of photons /sec at the surface and Adisk = the y
2 surface of the disk, c:n E = the average photon energy, Mev
<(E) = photon flux to dose rate conversion factor, R
c:n2 see IIr ~IIev 3 KIE) E D
R " 1.71 x 10 4
Y D = 2.03 x 10-5 g(g) g 3
~
R The dose rate at the centerline and bottom of a cylindrical shell can be calculated using the equation:
1730 311
47
_~Qt c 719 h I[y )
$=1A ARCTAN Y
9
.M f> Nc) where:
g I
SA = y/sec-ft h,
l gg H = height of the shell from
" Q.... _ _ ~,J 1
the receptor point, ft R = radius of the cylindrical shell, ft To approximate the correct dose rate, it is necessary to assume another cylinder directly under the first cylinder (a mirror image of the first) so that the total dose rate from the shell will be approximated by the equation:
arctan (H)/R) + S 4=SA A arctan (H /R) 2 7
7 Note that for this calculation H) = H2 and that H) + H2 = H (147.5 ft) or the total height used in the calculation of the surface area. The radius R is constant for each shell at 73.8 ft.
This reduces to the SA x arctan ("l) equation o = 2 x 7
'T Salving for 9:
$=2x A x arctan (N }
3 i
r r
arctan(M)
,=S A
e = s (arctan (1))
g
$=3 x 0.785 g
1730 312 Y
48, where S = the number of photons /sec at any point on the surface 2
A = surface area of the cylindrical shell, ft 3
4 = S, x 0.785 4
2 (6.84 x 10 ft )
$ = 0.785 S[ )
6.84 x 10 as given before Dose rate =
OR = S x c(E) x E or DR = (0.785
) c(!) E S 6.84 x 10-6 DR = 1.148 x 10-5,(g) g 3 The total dose from the plateout source to a point in the containment center is simply the sum of the dose rates frem the shell and the dose rate frem the disks. This means UNT = DRcyl + ORdisk Since E is identical for either case at a particular time, c(!) which is a function of E will also be identical for the calculations of the dose rates frcm the disk cr the cylindrical shell at the time chosen. Also, the source is assumed to be distributed uniformally over the surface.
Therefore, the total dose rate equation for the plateout scurce can be simplified to DR = 1.148 x 10-5 c(E) E S + 2.03 x 10-5,(g) g 3 7
y DR = 3.178 x 10-5,(g) g 3 T
y 1730 313 9
49 Table C-1 lists the appropriate values used by the staff in the calculation of the dose rate contribution to the receptor point on the containment centerline. Table 9 lists the Iodine Activity as a function of time and also presents the dose rate and integrated doses as a function of time for a 30 day period.
1730 314 e
1
50 FACTORS FOR DOSE RATES IN SUBCCMPARTMENTS DOSE RATES (R/Hr)
Y of Radius PT 4 (Center)
PT5 (Edge) 100 1
0.485 75 0.769 0.375 50 0.526 0.259 25 0.269 0.134 10 0.109 0.055 5
0.055 0.027 Multiplying the dose rate in the containment center at a time step n by the above factor for the fraction of the containment radius concerned will yield the dose rate at the center or edge of a subcompartment'for the same time step.
This model assumes an equal concentration in both the containment and the subcompartment. Also both volumes are represented as spheres.
10 3 Exa.1ol e : Containment Vol. 1 x 10 cm Ro = 1336cm 7 3 I
~
Subcompartment Vol.1 x 10 cm Ro=lT33.6cm n
l I33ib Ro is 10". of Ro 0
Dose rate at center of containment is 1 x 10 R/Hr Dose rate at center of subcompartment is 8
7 1 x 10 R/Hr 0.109 = 1.09 x 10 R/Hr Dose rate at edge of subcompartment is 8
6 1 x 10 R/Hr 0.055 = 5.5 x 10 R/Hr 1730 315
~~
51 TABLE C-1: DOSE RATE CALCULATION TO A POINT IN THE CENTER OF CONTAINMENT FROM THE PLATEOUT SOURCE
= 1.148 x 10-5, g(g), g, 3 Dose RateShell = CRCYL disk = 2.03 x 10-5 g(g), g, 3 Dose Rate
= DR 01sk Dose Rate
= DRT = DRCYL+UblSK = 3.178.x 10 -@ES
~
T 1 ft K(E) = 1.87 x 10-6 R em - SEC * (30.48 cm)
MEV HR (1.87 x 10-6)(1.076 x 10-3) = 2.102 x 10~9 R" h
EV 2
R-ft SEC Photon Spectra w/ Sprays Dose Rate w/ Sprays Time MEV g
.g(g) MEV-HR Ooerating,(v/SEC)
Ooerating, R/HR (hr) 0.0
.888 2.012-9 0.0 0.0 0.03
.887 2.012-9 9.85 +17 5.59 +4 0.07
.886 2.012-9 1.85 +18 1.05 +5 0.14
.884 2.012-9 2.44 +18 1.38 +5 0.20
.882 2.012-9 2.62 +18 1.48 +5 0.25
.880 2.012-9 2.68 +18 1.51 +5 0.40
.876 2.023-9 2.65 +18 1.49 +5 0.50
.873 2.023-9 2.57 +18 1.44 -5 0.75
.866 2.023-9 2.38 +18 1.33 +5 1.00
.860 2.023-9 2.22 +18 i.23 +5 2.00
.839 2.034-9 1.74 +18 9.44 +4 8.00
.763 2.055-9 8.30 +17 4.14 +4 24.00
.569 2.0 98 -9 4.16 +17 1.58 +4 60.00
.401 2.098-9 2.38 +17 6.36 +4 96.00
.357 2.098-9 1.83 +17 4.36 +3 172.00
.332 2.098-9 1.20 +17 2.66 +3 298.00
.330 2.098-9 8.20 +16 1.80 +3 394.00
.330 2.098-9 5.81 +16 1.28 +3 560.00
.330 2.098-9 3.20 +16 7.04 +3 720.00
.330 2.098-9 1.81 +16 3.98 +2
+ neglects correction factor for activity frem decay daughters.
- Interpolation by inspection from table from Fodoraro Ref.16.
1730 3l6
52 APPENDIX G: SUMP GAMMA DOSE RATE CALCULATION AT THE SUMP ShRFACE To calculate the dose rate and integrated doses from the f adine activity and 1% fission product solids in the containment sump, the sump water 9 3 volume of 44,156 ft3 (s1.2 x 10 cm ) was modeled as a cylindrical slab
~
with an equivalent radius of 75 ft. and a depth of 2.5 ft. The time-dependent fodine activity in the sump is shown in Table 4, and the activity was assumed to be uniformly distributed throughout the sump water. The dose rate at the surface of the sump was calculated using an infinite slab geometry model and neglecting bufiding.
D = h (1-E (ut))
k E
2 where: 0 = dose rate (R/hr) 3 S = the volumetric source (photons /cm -sec) y a = total linear attentuation coefficient (cm'I) for photons with Energy E in water t = the slab thickness k = the photon flux to dose conversion factor 2
see R
cm Hr Mev E = the average photon energy (Mev)
E (pt)= the exponential integral function, E (ut) =,
leydy 2
2 y
The equation given above can be approximated for ut>1 and E (at) 1 as:
2 o
kE This equation was used to calculate the iodine dose rates shown on Table 9.
e 1730 317 t
53 Consistent with Regulatory Guide 1.7, one percent of the equilibrium inventory of solid fission product particle activity was assumed to be reinsed to the sump at time zero. Since we could not calculate the specific contribution from individual solids isotopes, the photon decay energy ( c)for1% f the solid fission produces from fission of U-235 as a function of time was taken frem Table 2.8 of SANDIA report SAND 78-0091, Reference 7.
The dose at the surface of the sump from the solid particu-late fission products was calculated using the equation:
D=hk where in this case Sv = the volumetric energy source strength (se a) 3 In deternining the values for u and k it was assumed that the average photon energy for the mix of solid fission products was the same as for the iodine isotopic mix.
The dose rate at the surface of the sump due to solid particle decay is also shown on Table 9.
Because the solids were assumed in the sump at time :ero, the solid fission product activity dominates the total dose and dose rate until the sprays operate. Once the sprays operate, however, the solid fission produc*a account for only a small fraction of the total dese rate at the surface of the sump (<10% at.25 hour2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br />). However, at later times greater than about 100 hrs the solid particle activity becomes the dominant contributor to the sump surface dose rate.
1730 318 O
54 References 1.
A. K. Postma & R. Zavadoski, " Review of Organic Iodide Formation Under Accident Conditions in Water Cooled Reactors," WASH-1233 October 1972, pp 62-64.
~
2.
Note, R. B. Minogue to R. F. Fraley, October 25,1975, " Response to Request for Additional Information Concerning Regulatory Guide 1.89 on Qualification of Class lE Equipment."
3.
E. A. Warman and E. T. Boulette, " Engineering Evaluation of Radiation Environment in LWR Containments". Stone and Webster Engineering Co., June 1976.
4.
M. J. Kolar and N. C. Olson, " Calculation of Accident Doses to Equipment Inside Containment of Power Reactors". Commonwealth Associates, November 1975.
5.
ORNL/NUREG/TM-102, " Nuclear Decay Data for Radionuclides occurring in Routine Releases from Nuclear Fuel Cycle Facilities" Edited by D.C. Kocher, August,1977.
6.
E. Normand and W. R. Determan "A Simple Algorithm to Calculate the Immersion Dose," American Nuclear Society Transactions, June 1974 fleeting.
1730 319
O e
APPENDIX H 1730 320
i APPENDIX H STANDARD QUESTION ON ENVIRONMENTAL QUALIFICATION OF CLASS IE EQUIPMENT (PSB Standard Question #4)
(ICSB Review Reminder #23, Rev.1)
In order to ensure that your environmental qualification program confoms with General Design Criteria 1, 2, 4 and 23 of Appendix A and Sections III and XI of Appendix B to 10 CFR Part 50, and to the national standards mentioned in Part II " Acceptance Criteria" (which includes IEEE Std 323) contained in Standard Review Plan Section 3.11, the following infomation on the qualification program is required for all Class 1E equipment.
1.
Identify all Class 1E Equipment, and provide the following:
Type (functional designation) a.
b.
Manufacturer c.
Manufacturer's type number and model number d.
The equipment should include the following, as applicable:
- 1) Switchgear
- 2) Motor contrcl centers
- 3) Valve operators
- 4) Motors
- 5) Logic equipment
- 6) Cable
- 7) Diesel generator control equipment
- 8) Sensors (pressure, pressure differential, temperature and neutron)
- 9) Limit Switches
- 10) Heaters
- 11) Fans
- 12) Control Boards 13)
Instrument racks and panels
- 14) Connectors
- 15) Electrical penetrations j77n 791 3 / JV JLi
- 16) Splices
- 17) Terminal blocks
Categorize the equipment identified in (1) above into one of the 2.
following categories:
Equipment that will experience the environmental conditions a.
of design basis accidents for which it must function to mitigate said accidents, and that will be qualified to demonstrate operability in the accident environment for the time required for accident mitigation with safety margin to failure.
Equipment that will experience environmental conditions of b.
design basis accidents through which it need not function for mitigation of said accidents, but through which it must not fail in a manner detrimental to plant safety or accident mitigation, and that will be qualified to demonstrate the capability to withstand any accident environment for the time during which it must not fail with safety margin to failure.
Equipment that will experience environmental conditions of c.
design basis accidents through which it need not function for mitigation of said accidents, and whose failure (in any mode) is deemed not detrimental to plant safety or accident mitigation, and need not be qualified for any accident environment, but will be qualified for its non-accident service environment.
Equipment that will not experience environmental conditions d.
of design basis accidents and that will be qualified to 1730 322
demonstrate operability under the expected extremes of its non-accident service environment. This equipment would normally be located outside the reactor containment.
3.
For each type of equipment in the categories of equipment listed in (2) above provide separately the equipment design specification requirements, including:
a.
The system safety function requirements.
An envircnmental envelope as a function of time which includes b.
all extreme parameters, both maximum and minimum values, ex-pected to occur during plant shutdown, normal operation, abnormal operation, and any design basis event (including LOCA and MSLB), including post event conditions.
Time required to fulfill its safety function when subjected to c.
any of the extremes of the environmental envelope specified above.
d.
Technical bases should be provide to justify the placement of each type equipment in the categories 2.b and 2.c listed above.
Provide the qualification test plan, test set-up, test procedures,.
4.
and acceptance criteria for at least one of each group of equipment 1730 323
of (1.d) as appropriate to the category identified in (2) above.
If any method other than type testing was used for qualification (operating exper.ience, analysis, combined qualification, or on-going qualification), describe the method in sufficient detail to permit evaluation of its adequacy.
5.
For each category of equipment identified in (2) above, state the actual qualification envelope simulated during testing (defining the duration of the hostile environment and the margin in excess of the design requirements).
If any method other than type test-ing was used for qualification, identify the method and define the equivalent " qualification envelope" so derived.
- 6.
A summary of test results that demonstrates the adequacy of the qualification program.
If analysis is used for qualification, justification of all analysis assumptions must be provided.
- 7.
Identification of the qualification documents which contain detailed supporting information, including test data, for items 4, 5 and E.
In addition, in accordance with the requirements of Apper. dix B of 10 CFR 50, the staff requires a statement verifying: 1) that all Class 1E equipment has been (OL) or will be (CP) qualified to the program described above, and 2) that the detailed qualification information and test results are (or will be) available for an NRC audit.
1730 324
- For applications for construction permits, it is acceptable to state that items 6 and 7 will be supplied in the initial applica-tion for an operating license.