ML20054G256
| ML20054G256 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 06/16/1982 |
| From: | Vandewalle D CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| TASK-03-04.A, TASK-3-4.A, TASK-RR NUDOCS 8206210326 | |
| Download: ML20054G256 (6) | |
Text
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CORSum8f3 Power C0mpany Nmselear Licensmg Administrator General offices: 1945 West Parnell Road, Jackson, MI 49201 * ($17) 788-1636 June 16, 1982 Dennis M Crutchfield, Chief Operating Reactors Branch No 5 Nuclear Reactor Regulation US Nuclear Regulatory Commission Washington, DC 20555 DOCKET 50-155, LICENSE DPR BIG ROCK POINT PLANT - SEP TOPIC III h.A TORNADO MISSILES Consumers Power Company letter dated March 16, 1982, provided the IGC with Consumers Power Company evaluation of SEP Topic III-4. A, Tornado Missiles, for the Big Rock Point Plant. As a result of NRC's evaluation of Consumers Power Company March 16, 1982 submittal, the ImC requested additional information in order for the staff to complete their review of the subject SEP topic.
The attached documents furnish the IBC with the requested information.
The enclosure incorporates Consumers Power Company responses to the five (5) NRC questions. The enclosure also contains the Big Rock Point Plant floor plans of certain applicable structures and related equipment. A complete set of these drawings will be transmitted to the NRC's Big Rock Point Plant Integrated Assessment Project Manager (Ray Scholl). However, these drawings vill not be submitted along with this letter due to the volume of drawings provided.
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General Offices; 212 West Michigan Avenue, Jackson, MI 49201 e (517) 788-0550 June 16, 1982 Dennis M Crutchfield, Chief Operating Reactors Branch No 5 Nuclear Reactor Regulation US Nuclear Regulatory Co==ission Wachington, DC 20555 DOCKET 50-155, LICENSE DPR BIG ROCK POINT PLANT - SEP TOPIC III L.A TORNADO MISSILES Consumers Power Company letter dated March 16, 1982, provided the NRC with Consumers Power Company evaluation of SEP Topic III h.A, Tornado Missiles, for the Big Rock Point Plant. As a result of DEC's evaluation of Consumers Power Cc=pany March 16, 1982 submittal, the NRC requested additional information in order for the staff to ec=plete their review of the subject SEP topic.
The attached documents furnish the NRC with the requested information.
The enclosure incorporates Consumers Power Company responses to the five (5) NRC questions. The enclosure alsc contains the Big Rock Point Plant floor plans of certain applicable structures and related equipment. A cc=plete set of these drawings will be transmitted to the NRC's Big Rock Point Plant Integrated Assessment Project Manager (Ray Scholl). However, these drawings will not be submitted along with this letter due to the volume of drawings provided.
David J VandeWalle (Signed)
David J VandeWalle Nuclear Licensing Administrator CC Ad=inistrator, Region III, USNRC NRC Resident Inspector - Big Rock Point J
SYSTEMATIC EVALUATION PROGRAM BIG ROCK POINT PLANT SAFETY TOPIC III-4.A TORNADO MISSILES REQUEST FOR ADDITIONAL INFORMATION 1.
"The licensee's analysis of ~ tornado missiles concluded that the reactor building (a steel spherical shell) would not be penetrated.
The licensee is requested to provide the details of this analysis, including all equations used, supporting data, and supporting references."
Answer A.
The following supporting data / references were used in the analysis of the steel spherical shell:
1)
" Structural Design of the 130 foot Diameter Spherical Containment Vessel for the Big Rock Point Nuclear Plant," Chicago Bridge and Iron Company, Rev 1A, June 29, 1961 2)
Design of Structures for Missile Impact, BC-TOP-9A, Rev 2 (September 1974), Bechtel Power Corporation 3)
K.P. Buchert, " Buckling of Shell and Shell-Like Structures," K.P. Buchert and Associates, 1973 4)
" Missiles Generated by Natural Phenomena," U.S. NRC Standard Review Plan, Section 3.5.1.4.
B.
The steel spherical shell was analyzed in the following manner:
1)
The 1-inch diameter rod was analyzed for penetration characteristics; the utility pole was analyzed for energy / structural response characteristics.
2)
The critical buckling stress was determined from:
Tcr =.35 net (from Reference 3)
R where n = 1 (from Reference 3)
R = radius in inches t = thickness in inches E = modulus of elasticity 0162n 1
1 J
- 3) Tha paridional stress (banding end acmbrana) ces 7
determined to control buckling and is defined as:
I CP Bending:
Tb=
=
8 S
1/6 t N$
CP Membrane: Tm =
=
t t
where t
= thickness in inches C,
= 0.14 (from Reference 3)
C,
= 0.19 (from Reference 3)
P
= applied load 4)
The minimum load that causes buckling was determined by equating the critical buckling stress with the meridional stress.
5)
The approximate deflection under the buckling load is calculated as follows:
w=C, RP (from Reference 3) 2 Et where P = load in kips R = radius in inches t = thickness in inches E = modulus of elasticity C, = -0.275 (from Reference 3) 6)
The kinetic energy of the utility pole missile is determined as:
Mm Vs*
(from Reference 2) 2 2 (Mm + Me) 0162n 2
ehoro Mm = mass of the missile Vs = velocity of the missile Me = A 3di 9
A = contact
- area of missile t = thickness of plate g = acceleration of gravity y = mass density of steel 7)
The energy of the utility pole was dissipated into the steel spherical shell as the steel spherical shell underwent the following deformation:
A = 2w + KE F
This calculated deflection was determined not to affect any safety-related systems / components located inside the steel spherical shell.
2.
"The Licensee's analysis of tornado missiles provided a list of the minimum systems regired to achieve and maintain safe shutdown condition.
In the staff's evaluation for SEP Topic VII-3, " Systems Required for Safe Shutdown" the list of minimum systems included the core spray system and post incident cooling system which were not included in the tornado missile evaluation.
The licensee is requested to identify the tornado missile protection for the components and cabling of the core spray system and post incident cooling system."
Answer During our review, we found that SEP Topics are sometimes related but utilize different guidelines to satisfy the postulated event (s).
The guidelines utilized for Big Rock Point differ for SEP Topics VII-3 and III-4.A as well as the minimum systems selected to achieve and maintain the plant i
in a safe shutdown condition.
SEP Topic VII-3 considers a postulated loss-of-coolant accident (LOCA) concurrent with a loss of offsite power.
The review utilized General Design Criteria 1, 2, 3, 4, 5, 34, and 35 of 10 CFR 50, Appendix A l
l l
l 0162n 3
t a
1 (ehich, in part, rcquires the systems to be safety grada, capable of performing a safety function assuming the loss of offsite power as indicated above, and also assumes a single failure.)
SEP Topic III-4.A considers a postulated tornado event concurrent with loss of offsite power.
The review utilizes Section 3.5.1.4 (Standard Review Plan), which states "at the operating license stage, applicants who were not required at the construction permit stage to design one of the above missile spectra and the corresponding velocity set, should show the capability of existing structures and components to withstand at least missiles "C" and "F."
From this criteria, we do not postulate that an accident would occur concurrent with the tornado event, unless the missile (s) could cause an accident.
From our review of SEP Topic III-4.A, we find that "C" and "F" missiles do not penetrate the reactor building steel spherical shell (Page 3, Paragraph 4.E.1 of the SEP).
Therefore, no LOCA is postulated for the systems within the steel spherical shell during a tornado event nor is containment integrity breeched for a postulated pipe break (which could potentially cause a LOCA) from a missile strike in systems located outside the steel spherical shell.
Consequently, the core spray system and the post incident cooling system (enclosure spray) are not needed for this event, and the systems and/or components listed on Page 2, Paragraph 4.0 of the SEP are satisfactory.
Because of the above, the components and cabling for the core spray system and the post incident cooling system need not be considered.
3.
"The spent fuel pool cooling system was not included in the licensee's analysis of tornado missiles.
In order for the staff to complete its assessment of the affects of tornado missiles, the licensee is requested to identify the tornado missile protection for the components and cabling of the spent fuel pool cooling system."
Answer The spent fuel pool cooling system is located inside the steel spherical shell and is adequately protected.
- However, all cabling associated with the reactor building functions (including spent fuel pool cooling) passes through the electrical penetration room.
This room has been identified as being susceptible to tornado missiles from the east side.
4.
"The licensee's analysis of tornado missiles indicated that the safety-related components in the turbine building, i
service building, core spray equipment room and the electrical penetration room were vulnerable to tornado 0162n 4
missiles.
In order for the staff to assess the vulnerability of the components in these areas, the licensee is requested to provide plan and elevation drawings which-indicate the material and thickness of all exterior and interior walls, floors, and roofs of these buildings."
Answer The following drawings identify the material and thickness of walls, floors, and roofs.
Note:
All drawings are Bechtel Drawings under Job 3159.
General layout:
C-3 C-4 M-100 M-101 Screen house / diesel C-35 Generator room / discharge C-36 Structure C-37 C-40 Turbine building / service C-201 C-262 Building C-202 C-263 A-201 C-203 C-264 A-202 C-204 C-266 A-203 C-205 C-267 A-204 C-206 C-268 A-205 C-253 C-269 A-206 C-256 C-270 A-228 C-261 Turbine building passageway C-222 (electrical penetration C-224 room)
Air supply shed C-310 Fuel cask loading dock C-320 (core spray equipment C-321 room) 5.
Revision to Topic III-4.A, Paragraph 4.E.3:
The control room has reinforced concrete walls:
4'-6" thick on the north side, 3'-0" thick on the west side, and l'-0" thick on the east sid3.
The south wall consists of 1/2 inch thick steel plate cover over a partition wall, which contains two windows and a door.
The control room roof.
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