ML19290E741
| ML19290E741 | |
| Person / Time | |
|---|---|
| Site: | 07100107, 07106144 |
| Issue date: | 02/01/1980 |
| From: | Dumas D NEW ENGLAND NUCLEAR CORP. |
| To: | NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| Shared Package | |
| ML19290E735 | List: |
| References | |
| 15460, NUDOCS 8003140464 | |
| Download: ML19290E741 (21) | |
Text
h 7
knmA New England Nuclear nEul.dD
- ',,; O
'1 '.O N
. ' c.E G.
, s _ t, CG.<.e % bruary 1, 1980 w ey SECTION Director of Nuclear Material Safety F. Standards Nuclear Regulatory Commission Washington, D.C.
20555
Dear Sir:
This letter is being generated to satisfy the requirements of 20 CFR 71.
New England Nuclear is intending to ship Type B quantitics of Radio-active Waste via Chem Nuclear. The following information is being sup-plied to you under this part.
Shipper:
New England Nuclear Corporation NRC Lic#:
20-00320-13 Cask Supplier and Owner:
Chem Nuclear Systems, Inc.
NRC Cask approval #:
USA /6144/B Cask ID and Type:
15-160B, Type B We have in our possession and will comply with all Certificates Quality Assurance programs and documents relative to the use and maintenance of the packaging and will comply to all applicabic parts of 49 CFR 173, 14 CFR 103 and 46 CFR 146.
- t tw>: v' +
Dennis 0.
Dwnas Corporate Di rect or, Radiat ion Protect ion mqr -MM
.zgefy -
T i#TN 1?b Yv 0 601 Treble Cove Road, North Billerica, Massachusetts 01862 Telephone (617) 667-9531 Telex 94-7488 8 0 0314 ogy
TDK
?' 90f3.
gE;EWEP l
Nuclear
.:.. c 3 9
.- pc., i 1
-y February 7, 1980
-c.
St Mr. Richard Rawl Office of Hazardous Materials Transportation Materials Transportation Bureau U.S. Department of Transportation 2100 Second Street, S.W.
Washington, D.C.
20590 Subj ect :
Application for Certificate of Competent Authority, IAEA Type B (M) Packaging.
Gentlemen:
NL Industries requests issuance of a Certificate of Competent Authority covering the NLI 10/24 Spent Fuel Shipping Cask as a Type B (M) package.
The Nuclear. Regulatory Commission has issued, to NL Industries, Certificate of Compliance No. 9023 authorizing use of this package for shipment of radioactive material.
To assist in the Type B (M) package design review a comparison has been made between the requirements of IAEA Safety Series No. 6,
" Regulations for the Safe Transport of Radioactive Materials" (1973 Revised Edition) and the requirements of the Nuclear Regulatory Commission given in 10 CFR Part 71.
Specific requirements of IAEA Safety Series No. 6 for which a corresponding requirement in 10 CFR Part 71 could not be found are listed in Attachment "A ' along with a discussion relating to how the NLI 10/24 package relates to the specific IAEA requirement.
Questions concerning this application should be directed to the undersigned.
Very truly yours,
'~ b
,h%.Y _
D Charles E. Williams Engineering Manager q
y Attachgent b
cc: VCharles E. MacDonald
~
U.S. Nuclear Regulatory Commissicn
} v Nuclear Division /NL industries, Inc.
Foot of West Street, WilmingMn, Def.19801 Tel. (302) 656-1661 Mailmj AdSess P.O. Box 2046, Wilmington, Del.19899 i
Attachment "A" Listing of specific requirements of IAEA Safety Series !!o. 6 for which a corresponding requirement in 10 CFR Part 71 could not be found and a discussion as to how the f;LI 10/24 package relates to the specific IAEA requirement.
SECTION II - PACKAGING AND PACKAGE DESIGN ItEQUIItEMENTS GENERAL DESIGN IlEQUIREMENTS FOlt ALL PACKAGINGS AND PACKAGES 201.
The packaging shall be so designed that the package can be easily handled and can be properly secured in or on the con-veyance during transport.
The NLI 10/24 shipping packagc is equipped with four lifting trunnions at the top end of the package and two trunnions at the bottom end which are used to rotate the package from the horizon-tal shipping position to the vertical position for fuel loading.
The package is provided with an integral set of tie down lugs which interface with a corresponding set of tie down lugs that are welded to a specially designed rail car.
203.
A package of gross weight in excess of 50 kg shall be so designed as to enable safe handling to be done by mechanical means.
The NLI 10/24 package has four trunnions near the top of the pack-age which are the lif t points used in conjur-tion with specially designe0 lif ting rigs.
205.
Attachments and any other fe :tures on the outer surface of the packaging which could be us d to lift the packages shall be re-movable or otherwise rendered ;noperable for transport or shall be designed to support the weight of the package in accordar.ce with the requirements of para.204.
Q C /'.f.o
-w
'4
Page 2 There are no features on the outer surface of the package, other than those specially designed for lifting, that could be used to lift the packaging.
20G.
The outer layer of packaging shall be so designed as to avoid, as far as practicable, the collection and the retention of water.
20 ~l.
The external surfaces of packaging shall, as far as pract!-
cable, be so designed and finished that they may be easily decon-taminated.
The external surfaces of the packaging are snooth and free drain-ing. The finned area of the package would be covered either by a light gauge stainless steel cylinder or reinforced plastic to pre-vent contact between the fins on the package and the contaminated water in the spent fuel storage pool.
All other package surfaces are smooth and clear of potential collection spots.
208.
Any features added to the package at the time of transport which are not part of the package shall not reduce the safety of the package.
There are no features cdded to the package at time of transport which could reduce the safety of the package. The effect of all features of the packaging at time of transport have been taken into account in the safety analysis.
ADDITIONAL REQUIILEMENTS FOR TYPE A PACKAGES Note:
Paragraph 242 requires that Type B (M) packages shall meet the requirements specified for Type A packages.
t r? "
l ed
page 3
?
212.
As far as practicable, packaging shall be designed so that the external sufaces are free from protruding features.
The NLI 10/24 package has three features which protrude from the external surface of the package.
The three features are the lifting trunnions which are located in the head end forging of the package where damage would not result in the puncture and subsequent loss of shielding material; the turning trunnions which are 1ccated in the area of the bottom end forging again eliminating the concern of puncture and subsequent lou of shielding; and third is the tie down lugs which are located at each end of the water jacket. The package design incorporates the use of impact limiters mounted on each end of the package which are designed to protect the package i.nd the above mention-ed features during transport.
213.
The design of the packaging shall take into account the variations in temperature to which the packaging may be subjected during transport and storage. In this respect, -40*C and 70*C shall be considered as satisfactory limits to be used in the selection of the materials; special attention, however, must be given to brittle fracture over this temperature range.
The range of temperatures considered in the design of the tiLI 10/24 package is much greater than required by paragraph 213.
The materials used in the NLI 10/24 package are required to operate in the -40 C to 5000C range. All material used in the package, except the shielding material, is 300 series stainless steel.
214.
The design, fabrication and manufacturing techniques for welded, brazed, or other fusion joints shall be in accordance with national or international standards or with standards acceptable to the competent authority.
Page 4 The fabrication procedures require the use of welding operators and welding procedures which are qualified in accordance with the American Society of Mechanical Engineers and/or the American Welding Society codes.
215.
The package shall be capable of withstanding the. -ffects of any acceleration, vibration or vibration resonance which may arise during normal transport without any deterioration in the ef-fectiveness of the closing devices on the various receptacles or in the integrity cf the package as a whole. In particular, nuts, bolts and other securing devices shall be so designed as to prevent them from becoming loose or being released unintentionally, even after repeated use.
The vibration environment and the "g" loadings applicable to rail transportation are addressed in Section XI, Part 2.7 of the NLI 10/24 Safety Analysis Report.
The values established were used to evaluate the package integrity under normal con-ditions of rail transport.
218.
If the outer component of a containment system forms a separate unit of the packaging, it shallbe capable of being securely closed by a positive fastening device which is independent of any other pa'rt of the packaging.
The requirement is not applicable to the NLI 10/24 package.
There is no outer component of the containment system which forms a separate unit of the packaging.
221.
The containment system shall retain its radioactive contents under the reduction of ambient pressure to 0.25 kg/cm*.
The contair....ent system closures and seals are the only items effected by a reduction of ambient pressure. All other fea-tures of the containment system are not directly effected since t iey are enclosed by the outer structure of the package
Page 5 which consists of radiation shielding, stainless steel shells and end forgings. This reduction in ambient pressure results in an increase in pressure difference across the closure seals of approximately 11.25 psi.
The closure and seal designs are more than adequate to accommodate the increase in pressure difference across the seals.
222.
All valves, other than pressure relief valves, through which the radioactive contents could otherwise escape shall be pro-tected against unauthorized operation and shall be provided with an enclosure to retain any leakage from the valve.
There are two penetrations in the inner closure head cask flange which are used for venting and draining the cask cavity. These penetrations are equipped with 1 1/2 inch valved quick disconnect fittings. These fittings are housed in a stainless steel valve box which is bolted to the cask flange. The metal "0" ring seals in the valve box arrangement provide the pressure boundary for the containment system.
Access to the valve boxes can only be achieved by removing the 21/2 inch thick by 641/2 inch diameter outer steel closure head.
223.
A radiation shield which encloses a component of the packa-ging specified as a part of the containment system shall be so designed as to prevent the unintentionalreleaseof that component from the shield. Where the radiation sideld and such component within it form a separate unit, the radiation shield shall be capable of being securely closed by a positive fastening device which is independent of any other packaging structure.
The radiation shield is contained within the welded structure of the package.
The requirements of this paragraph are not appli-cable to the f1LI 10/24 package.
Page 6 226.
Type A packaging designed for liquids chall, in addition, be adequate to meet the conditions prescribed in para. 225 if the package is subjected to the tests specified in Section Vil, paras 715-717. Ilowever, these tests are not required when enough ab-sorbent material to absorb twice the volume of the liquid contents is witidn the containment and:
(a) The absorbent materialis within the radiation shield; or (b) The absorbent materialis outside the radiation sideld, provided that it can be shown that if the liquid contents were taken up by the absorbent material the resultant radiation level at the surface of the package would not exceed 200 mrem /h. '
This requirement is not applicable to the ilLI 10/24 package.
227.
Type A packaging designed for compressed or uncompressed gases shall, in addition, prevent loss or dispersal of the radioactive contents if thepackagingis subjected to the tests specified in Section VII, paras 715-717. Packages designed for tritium and argon-37, in gaseous form and in activities up to 200 Cl, shall be exempted from this requirement.
This requirement is not applicable to the tiLI 10/24 package.
BASIC ADDITIONAL REQUIREMENTS FOR TYPE B(U) PACKAGES flote:
Paragraph 242 requires that Type B (ii) packages shall meet the additional basic requirements for Type B (U) pack-ages.
228.
Type B(U) packages shall be designed to meet all the ad-ditional requirements specified for Type A packages.
This requirement has been met.
See the above responses to paragraphs 210 through 227.
Page 7 230.
A Type 13(U) package shall be so designed that, if it were subjected to the tests referred to below, it would:
(a) with regard to the tests specified in Section VII, paras 700-714, restrict theloss of radioactive contents to not more than X 10-6 per hour; A2 (b) with regard to the tests specified in section VII, paras 718-721, restrict the accumulated loss of radioactive contents to not more than A2 X 10-3 in a period of one week.
For (a) above, the evaluation shall take into account the external contamination limitations of Section V, para.502, and, for both (a) and (b) above, the A2 values for noble gases shall be those for the uncompressed state.
Tests required by (a) are tests for demonstrating ability to withstand normal conditions of transport.
Section XI, Struc-tural Analysis, Parts 2 and.3 of NLI 10/24 Safety Analysis Report has satisfactorily addressed the package integrity when subjected to the tests specified by 10 CFR 71, Appendix A.
Normal conditions of transport which delineates the same four basic tests.
There are some minor differences between the two sets of regulations none of which are significant except for the compression test.
The compression test specified by IAEA regulations is to be applied to all packages regardless of size.
10 CFR 71, Appendix A, does not require this test for packages exceed-ing 10,000 pounds.
It is not realistic to test packages the size of spent fuel shipping packages (20 - 100 tons).
There are no conditions encountered in normal transport of spent fuel shipping packages for which the compression test is appropriate.
For these reasons the compression test has not been addressed.
Page 8 The analysis shows that the integrity of the package has not been effected when subjected to the prescribed tests.
The most likely areas for leakage are the inner closure head gasket joint and the valve boxes which seal the penetrations to the contain-ment system.
In both cases the joint design and bolt preload requirements are such that the bolted joint never becomes loaded beyond the established preload of the bolt.
Thereby restricting relaxation in the gasketed ;9 int.
To verify design and fabrication the assembled package is tested before its first use.
The containment system is pressurized with helium gas and a mass spectrometer leak detector is used to de-
-6 tect leaks. A leak rate greater than 1 X 10 STP cc/sec is cause for rejection.
The procedure is delineated in Section XIV, Functional Testing, of the flLI 10/24 Safety Analysis Report.
This test adequately demonstrates the containment systems ability to restrict the loss of radioactive contents to c.ot more than A2 X 10-6 per hour. ANSI Standard N14.5, " Leakage Tests on Pack-ages for Shipment of Radioactive Materials" is used to translate the IAEA requirement into a leak rate which can be compared with the sensitivity of the leak test specified for the flLI 10/24 package.
The IAEA requirement is translated as follows:
Fission product gas inventories are taken as those listed in the AEC report, " Environmental Survey of Transportation of Radioactive Materials to and from Nuclear Power Plants", December,1972.
The only radionuclide of significant amount is krypton (Kr85).
The amount of activity in the void spaces of the fuel rods is given e tT;~Q
.L.v.
Page 9 3
as 3.4 X 10 curies / metric tons which is based on a burnup of 33,000 MWD /MTU and 150 days cooldown. The f1LI 10/24 package is designed to carry fuel having a maximum average burnup of 35,500 tiWD/MTU. An increase of 25% is made to the fission pro-duct gas inventory given in referenced AEC report to reflect the approximate 8% increase in burnup.
The total inventory of Krypton (Kr85) in the TILI 10/24 package is:
3 3.4 X 10 Ci/MTU X 1.25 X 4.75 MTU = 20,188 Ci It is conservatively assumed that the entire 20,188 curies is released to the containment system environment.
Following the above referenced AriSI standard (fil4.5), the permiss-ible leakage rate is expressed as:
L il flormal Conditions C;;
Where 3
L ; = permissible leakage rate m /sec or cc/sec.
g R ; = package containment requirement.
t X 10-6 per hour or A2 X 2.78 X 10~
Ci/sec.
A2 From Section IV, Table VII of the IAEA regula-85 tions A f r Kr uncompressed is 1000 curies.
2 Therefore
-10
-6 R = 1000 X 2.78 X 10
= 0.278 X 10 Ci/sec.
g C; = activity of medium that could escape in curies g
per cubic meters.
The free volume of a fully loaded f1LI 10/24 containment system is 2.157 3
cubic meters (m ) or 2.157 X 106 cc.
Therefore
Page 10 g=-f0
= 0.00936 Ci/cc 8
O Giving a permissible leakage rate of:
4
-fh10
= 29.7 X 10-6 cc/sec U
Lg=
=-
fl The sensitivity of the package leak test is 1 X 10 STP cc/sec which is more than adequate to prove the ability of the package to meet the permissible leakage rate.
Tests required by (b) are tests for demonstrating ability to with-stand accident conditions in transport.
Section XI, Structural Analysis, Part 4, of NLI 10/24 Safety Analysis Report, has satisfactorily addressed the package integrity when subjected to the tests specified by 10 CFR 71, Appendix B Hypo-thetical Accident Conditions which delineates the same four basic tests, Free Drop, Puncture, Thermal and Water Immersion.
The test parameters for the Free Drop and Puncture tests are the same for both NRC and IAEA regulations. There are some differences in the thermal test between the NRC and IAEA regulations.
The temperature, time and emissivity coefficient are the same but IAEA does not limit the absorption coefficient to 0.8.
In addition IAEA requires, when significant, consideration of convective heat input. These differences are not significant relative to the NLI 10/24 package.
The critical period for the NLI 10/24 package is not during the thermal test but af ter the 30 minute test period has elapsed. Dissipation of the internal decay heat load is Ar:f'"
.L,v a.s -
Page 11 hampered by the loss of the water in the neutron shield water jacket.
Consequently internal package temperature is higher than during the thermal test transient.
The thermal analysis,Section VIII of the NLI 10/24 Safety Analysis Report, estimates the metal temperature in the area of the inner closure head seal and containment system valve boxes to be 400 F.
Both the valve box seal and inner closure head seal are metal "0" rings made of Inconel and will withstand temperatures up to 13000F.
The water immersion test required by IAEA regulations differs fcom NRC in the required immersion depth,15m (49.2 f t) as com-pared to NRC requirement of 3 ft. Water pressure at a depth of 15m is about 21 psig.
The NRC regulations (10 CFR 71.32 (b))
requires the packaging to be subjected to an external pressure of 25 psig with no loss of contents.
Section XI, Structural Analysis, Part 2 of the NLI 10/24 Safety Analysis Report has satisfactorily addressed this requirement and should satisfy the IAEA water immersion test. The thermal and structural analysis supported by model testing as described in the NLI 10/24 Safety Analysis Report, shows that the integrity of the package has not been effected when subjected to the perscribed accident damage tests.
The most likely areas for leakage are the inner closure head gasket joint and the valve boxes which seal the penetrations to the containment system.
In both cases the joint design and bolt preload requirements are such that the bolted joint never becomes loaded beyond the established pre-load of the bolt thereby restricting relaxation in the gasketed joint.
dge To verify design and fabrication the assembled package is tested before its first use.
The containment system is pressurized with helium gas and a mass spectrometer leak detector is used to de-tect leaks. A leak rate greater than 1 X 10-6 STP cc/sec is cause for rejection. This test adequately demonstrates the containment systems ability to restrict the loss of radioactive contents to not more than A2 X 10-3 in a period of one week as prescribed by IAEA' regulation paragraph 230 (b). AriSI Standard fil4.5 " Leakage Tests on Packages for Shipment of Radioactive Materials" is used to translate the IAEA requirement into a leak rate which can be compared with the sensitivity of the leak test specified for the flLI 10/24 package. As previously established the only radionuclide of significant amount is krypton (r,r85) and the total inventory in the flLI 10/24 package is 20,188 curies.
It is conservatively assumed that the entire 20,188 curies is re-leased to the containment system environment.
Following the above referenced AriSI standard (14.5), the permics-able leakage rate is expressed as RA Accident Conditions LA, CA Where LA = permissible leakage rate m3 sec or cc/sec.
/
X 10-3 in one week or RA = package containment requirement Ap
-9 A X 1.65 X 10 Ci/sec. A I # E"85 uncompressed is 2
2 1000 curies.
Therefore
Page 13
-9 IIA = 1000 X 1.65 X 10
= 1.65 X 10-6 Ci/sec CA = activity of medium that could escape in curies per cubic meter or Ci/cc.
20,188 CA=
=.00936 Ci/cc.
2.157 X 106 Giving a pennissible leakage rate of:
LA=
A 1.65 X 10-6 = 176.28 X 10-6 cc/sec.
=
C
.00936 A
/
The sensitivity of the package leak test is 1 X 10-6 STP cc/sec which is more than adequate to prove the ability of the package to meet the permissible leakage rate.
231.
Type B(U) packages shall be so des!gned, constructed, and prepared for shipment that, undertheambient conditions spe-cified in para.232, they shall satisfy the conditions in 'a) and (b) below.
(a) IIeat generated within the package by the radioactive contents will not, under normal conditions encountered in transport (as demonstrated by the tests in Section VII), adversely affect the package in such a way that it will fail to meet the applicable requirements for containment and shielding if left unattended for a period of one week. Particular attention shall be paid to the effects of heat which may:
(i) alter thenrrangement, the geometricalform or the physi-cal state of the radioactive contents or, if the materialis en-closed in a can or receptacle (for exarnple, clad fuel ele-ments), cause the can, receptacle or material to melt; (11) lessen the efficiency of the packaging through differen-tial thermal expansion or cracking or melting of the radi-ation shielding snaterial; (iii) in combination with moisture, accelerate corrosion, (b) The temperature of the accessible surfaces of a Type B(U) package shall not exceed 50*C in the shade unless the package is transported as a full load.
232.
In applying para.231 above, the following conditions shall be assumed:
(a) ambient temperature 30*C; (b) insolation datanccording to Table !!!.
Page 14 The package design contains several unique features which pennit operation as a "zero release" system under normal conditions of transport and hypothetical accident conditions.
The design pro-vides double containment of the fuel assemblies in a dry environ-ment.
With the containment system filled with helium, the pressure under normal conditions of transport is 16.45 psig. If the assumption is made that all the fuel pins rupture.and there is a total release of fission preduct gas to the containment system environment, the maximum transport pressure would be 72.9 psig. Any increase in containment system temperature due to hypothetical accident conditions will be accompanied by a very small increase in pressure.
Maximum possible pressure is only 85.8 psig which occurs at the end of the fire accident only if all the BWR fuel pins rupture. There are no active mechanical connections such as pressure relief valves between the contain-ment system and the environment.
The containment system has drain and vent penetrations which terminate at valves located in the secondary containment space between the package inner and outer closure lids.
Decay heat is removed from the fuel to the cask by thermal radiation and conduction through an aluminum fuel basket.
Ileat_ is then transferred through the cask sides and ends by a combination of conduction, natural convection in the water filled neutron shield, and natural convection and radiation from the surfaces of the cask.
Being entirely passive this means of heat dissipation is highly reliable and does not require monitoring to assure operation.
The package can be left unattended for a period of more than one week without degradation of the package integri ty.
SUCO
Page 15 The temperature of the accessible surface of the package (pack-is always transported as a full load) will not exceed 82 C ar' 0
in the shade.
The accessible surface of the package in trans-port is the personnel barrier which completely surrounds the package.
233.
Packaging which includes thermal protection for the pur-pose of satisfying the requirements of the thermal test specified in Section VII, para.720, shallt,e so designed that such protection will remain effective if the packaging is sul'jected to the tests spe-cified in Section VII, paras 700-714 and 719. Any such protection on the exterior of the package shall not be rendered ineffective by conditions commonly encountered in normal handling or in accidents and not simulated in the tests referred to above, e.g. by ripping, cutting, skidding, abrasion or rough handling.
The NLI 10/24 package design does not rely on any thermal pro-tection device to satisfy the requirements of the thermal test specified in Section VII, paragraph 720.
SPECIFIC ADDITIONAL REQUIREMENTS Foil TYPE B(U)
PACKAGES Note:
Paragraph 242 requires that Type B (H) packages shall meet, "as far as practicable, the additional specific requirements for Type B (U) packages."
234.
Compliance with the permitted activity release limits shall depend neither upon filters nor upon a mechanical cooling system.
Page 16 The containment system does not require nor is it equipped with mechanical connections such as relief valves and filters.
Decay heat removal does not require the assistance of a mechanical cooling system to maintain the predicted package temperatures upon which activity release is evaluated.
235.
A nackage simil not incorporate a feature which is Intended to allow con inuous venting during transport.
The containment system does not require nor is it equipped with mechanical connections such as relief valves that would allow venting to the environment.
230 The package shall not include a pressure relief system from the containment system which would allow the release of radio-active material to the environment under the conditions of the tests specified in Section Vil, paras 700-714 and '.18-721.
See response to paragraph 235.
237 Where the maximum normal operating pressure (see Section 1, para.122)of thecontainment system added to any differen-tial pressure below mean sea-level atmospheric pressure to which any component of the packaging specified as part of the containment system may be subjected exceeds 0.35 kg/cm, that component shall 2
be capable of withstanding a pressure of not less than one and a half times the sum of those pressures; the stress at this latter pressure shall not be more than 75% of the minimum yleid strength and not more than 40% of the ultimate strength of that component at the maximum expected operating temperature,
Page 17 The f LI 10/24 package cannot satisfy this requirement. Itaximum 2
normal operating pressure exceeds 0.35 kg/cm resulting in stresses exceeding 75% of the minimum yield strength at operat-ing temperature.
ftLI package design criteria established an allowable operating stress level of 0.9 S at operating tempera-y ture.
See Section XI Structural Analysis, Part 1.1 and 3.0, tiLI 10/24 Safety Analysis Report.
238.
When the pt:kage at the muimum normal operating pressure (see Section I. para.122) is subjected to the thermal test specified in Section VII, para.720, the pressure in any com-ponent of the packaging specified as a part of the containment system shall be demonstrated not to exceed the pressure which corresponds to the minimum yield strength of that component at the maximum temperature which it would be expected to reach in the test.
The f1LI 10/24 package cannot satisfy this requirement.
IILI package design criteria established an allowable stress level greater than the minimum yield strength at the maximum expected operating temperature.
See Section XI Structural Analysis, Part 1.1 and 4.9.6, flLI 10/24 Safety Analysis Report.
230.
The package shall not have a maximum normal operating pressure (see Section I, para.122)in excess of 7 kg/cm2 (gauge).
The maximum normal operating pressure does not exceed 7 kg/cm2 (gauge).
If the assumption is made that all the fuel pins rup-ture and there is a total release of fission product gas to the containment system environment, the maximum normal operating pressure would be 5.125 kg/cm2 (gauge).
Page la 241.
The contalianent r:ystem of a package containing liquid shall not be impaired if the package in subjected to a temperature of -40*C under normal conditions of transport.
The containment system does not contain liquid.
The neutron shield material which surrounds the containment system is water which contains a sufficient antifreeze mixture to prevent freez-0 ing at -40 C.
ADDITIONAL ltEQUIllEMENTS FOlt TYPE It(M) PACKAGES 242 Type II(M) packages shall meet the requirements specified for Type A packages, the additional basic requirements for Type U(U) packages and, an far as practicable, the additional specific requirements for Type ll(U) packages.
The various requirements have been discussed under the appro-pria te paragraphs.
243. 3 A Type B(M) package shall be so designed that, if it were subjected to the tests referred to in Section VII, paras 709-714 and 718-721, it would restrict the loss of radioactive contents to not more than the act.vity limits specified in Table IV. The evaluation with respect to the tests specified in Section V11, paras 109-714, shall take into account the external contamination limitations of Section V, para.s02 The package meets the more restrictive requirements of para-graph 230.
244 If the pressure in the containment system of a Type 11(M) package could result in a stress exceeding, under the conditions of the tests in Section VII, paras 709-714 and 718-721, the minimum yield strength of any structural material of the containment system at the temperature which it would be expected to reach in M ~"""v the tents, the packaging shall be equipped with a pressure relief
"*O system to ensure that that minimum yield strength is not exceeded.
Page 19 Under the conditions of the tests in Section VII, paragraphs 709-714 and 718-721, the minimum yield strength of the material of the containment system is exceeded.
The NLI 10/24 Safety Analysis Report es~tablishes an accept-able design criteria (Section XI, Part 1.1) against which package integrity is evaluated. The structural analysis, which employs finite element computer techniques, considers all loading conditions resulting from the prescribed condi-tions of normal transport and the hypothetical accident tests.
In all cases the pressure in the containment system is not the dominant load conditior, contributing to the resulting stre!,s levels.
Therefore equipping the containment system with a pressure relief device would not change the stress condition such that the minimum yield strength of the mater-ial would not be exceeded.
The Safety Analysis Report establishes the package integrity under all conditions of loading without the need of a pressure relief device.
.