ML17309A251
| ML17309A251 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 04/16/1982 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Maier J ROCHESTER GAS & ELECTRIC CORP. |
| References | |
| TASK-03-04.A, TASK-3-4.A, TASK-RR LSO5-82-04-048, LSO5-82-4-48, NUDOCS 8204190259 | |
| Download: ML17309A251 (23) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, O. C. 20555 April 16, 1982 Docket No. 50-244 LS05 04-048 Mr. John E. Maier Vice President
'lectric and Steam Production Rochester Gas 8 Electric Corp.
89 East Avenue Rochester, New York 14649
Dear Mr. Maier:
SUBJECT:
SEP TOPIC III-4.A, TORNADO MISSILES R.E.
GINNA NUCLEAR POWER PLANT 8
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C Enclosed is our final eva'tuation of'SEP Topic III-4.A.
Following exchanges between your staff and ours.,
we have revised the previ-ous evaluation.
The evaluation concludes that portions of systems important to safety are not adequately protected from tornado missiles.
The evaluation will be a basic input to the integrated safety as-sessment of your facility.
The assessment may be revised in the future if your facility design is changed.
Sincerely,
Enclosure:
As stated Dennis M. Crutchfield, ief Operating Reactors Branch No.
5 Division of Licensing cc w/enclosure:
See next page
R.
E. Ginna Docket No.
50-244 Revised 3/30/82 CC Harry H. Voigt; Esquire
- LeBoeuf, Lamb, Leiby and MacRae 1333 New Hampshire Avenue, N.
W.
Suite 1100 Washington, D. C.
20036 Mr. Michael Slade 12 Trailwood Circle Rochester, New York 14618 Ezra Bialik Assistant Attorney General Environmental Protection Bureau New Yo'rk State Department of Law 2 World Trade Center New York, New York 10047 Resident Inspector R. E. Ginna Plant c/o U. S.
NRC 1503 Lake Road
- Ontario, New York 14519 Director, Bureau of Nuclear Operations State of New York Energy Office Agency Building 2 Empire State Plaza
- Albany, New York 12223 Supervisor of the Town of Ohtario 107 Ridge Road West
- Ontario, New York 14519 Dr. Emmeth A. Luebke Atomic Safety and Licensing Board U. S. Nuclear Regulatory Commission Washington, D. C.
20555 Dr. Richard F. Cole Atomic Safety and Licensing Board U. S. Nuclear Regulatory Commission Washington, D. C.
20555 U. S. Environmental Protection'Agency Region II Office ATTN:
Regional Radiation Representative 26 Federal Plaza New York, New York 10007 Herbert Grossman, Esq.,
Chairman Atomic Safety and Licensing Board U. S. Nuclear Regulatory Commission Washington, D. C.
20555 Ronald C. Haynes, Regional Administrator Nuclear Regulatory Commission, Region I 631 Park Avenue King of Prussia, Pennsylvania 19406
R E. Ginna Nuclear Power St'aloe TRIA. A TORNAOO NISSILES I~
INTROOUCTION General Oesign Criteria 2 and 4 of Appendix A, 10 CFR Part 50, require, respect-ively, that structures,
- systems, and components important to safety be designed to withstand the effec.s
- o. natural phenomena, and also be protected frcm missiles originating from events and conditions outside the plait.
Tornaoo missiles, i.e., objects and debris blown before tornado winds, are hazards which may oe considered as included in either or both of these criteria.
Review topic III-4.A directs the evaluation of the plant's protection agains these hazards to deternine whether or not it is sufficient to assure:
I.
The integrity of the reactor coolant pressure
- boundary, 2.
The capability to shut the reactor down and maintain it in a safe shutdown condition, and 3.
The capability to prevent accidents which could result in offsite exposures in excess of the dose guidelines of 10 CFR Part 100.
II.
RE'/I=A CR ITER'.DN A structure,
- system, or component is considereo to be aoecuately protected from a pos.ulated missile if either it itself or a struc:ure which surrounds ft is sufficient to stop tha missile without per.oration or collapse.
No credit is given to masonry block walls for tornado missile protection.
III.
RELAT'0 SAF=)f TOP'.CS Topic II-2.A, "Severe ')cather
?hencmena".
desc.ibes the tornado character-istics,or the plant.
Topic III-2, "'Aind and Tornado Loadings" reviews the capabiIfty of Ne plant struc.ores, systems and ccmponents to withstand wind loadings.
Topic VII-3, "Systems Required for Safe Shutdown" reviews those systems needed to achieve and maintain the plant in a safe shutdown conditSon.
IV.
REVIFA GUIDANC'2 Regulatory Guide 1.78 defines the characteristics of the tornadoes to be used as design bases at sites within the coterminous United States.
'PASH-1300,
'Technical 8asis for interim Regional Tornado Criteria," refer need by that I
guide, cantainq mare detailed information concerning tornado incidence and I
severity.
Regulatory Guide 1.117 contains instructions by which structures,
- systems, and 4
components imaortant to safety can be identified in any plant design.
Standard Review Plan (SRP) 3.5.1.4, Revision 1, "Missiles Generated by Natural Phenomena," lists objec.s which may.be postulated to be hurled as missiles by tornado winds.
The diversity of objects, and the velocities and altitudes they are to be postulated ta attain as missiles, are given in this plan for each of three regional design basis tornadoes,
- and, since the review has been revised, for each of thr e time intervals in which a canstructian permi application was filed.
For a plant, which, like Ginna, is lacated in tornado Region I and for which an applicatian for a cons ructian permit was made prior to 1973, the appropriate design basis missiles are:
1.
A steel rad, 1-inch diameter and 3-feet long, weighing 8 pounds, st iking endrin a
317 fe t/secanC (97 meters/sec),
which corresponds.to 6G" of 360 MPH wind velocity.
2.
A waaden u ility pale, 35-fe t long, weighing 1490 Pounds, striking end-an at 211 feet/second (64 meters/sec) at elevations'ess than 30 feet above the highes grade level within 1/2 mile of the plant.
This'arresponds ta 40" af 360 4IPH wind velocity.
As noted in SEE Topic II-ZAtornadoes are significantly less frequent and less severe in the vicinity of Ginna than in most of Tornado Region I.
The design basis tornado at Ginna has, therefore, been assigned a maximum wind speed of 250 mph (111 meters/sec).
For this wind speed, the appropriate design basis missile velocities given above are revised to:
1.
Steel rod, 60~ of 250 mph, or 219 feet/second (67 meters/sec).
2.
Mooden utility pole, 4C" of 250 mph, or 146 feet/second (45 meters/sec).
V.
EVALUATION A.
Struc.ures s stens and ccmoonents important.o safety The reactor is housed within a steel-reinforced concrete containment building approximately a meter thick, surrounoed by a steel-reinforced concrete structure, largely below gr ade, which is surmounted by steel structures with she : metal siding.
The screenwell house is a similar steel superstructure on a concrete
- basement, while the diesel generator building is a steel structure attached to the main plan: bu'.Idings.
The hissile barrier protection described in I.2, above, is required to assure capacity to achieve and maintain saf shu.dcwn of the reactor.
The systems needed for this capacity are treated fn topics V-IO.B, V-II.A, V-II.B, VII-3 and IX-3, and r por.ad i" "SE7 Review of Safe Shut-down Systems (Rev. I)," da.
d Nov~er 14, IgM.
These systems ar 1.
Auxiliary feed<<atar system Z.
Standby auxiliary feee~ater systems.
3.
Main steam systan out to atmospheric dump valves 4.
Service water system
5.
Chemical volume control system
{i.
Component cooling system 7.
Residual heat removal system 8.
Emergency power supply, including transformers.
The missile barrier protection required in f.3, above, in addition to the reactor coolant pressure boundary in 1.1, and the eight systems above, further include the control room and its instrument and control caamunications
<<ith the otner sys.ems and structures listed, and.the spent fuel pool.
8.
Missile barriers which meet current reauirements Although Ginna was designed and built prior to the development of the Standard Review Plan, a portion of the plant has sufficient str'ength to meet current (since
- June, 1977) missile protection requirements.
This portion consists of the containment.building and the lower concrete structure of the control room, auxiliary, and intermediate buildings.
( The intermediate level of the auxiliary building is protected from above by the upper level concrete floor) Safety systems housed in this portion are the reactor coolant pressure
- boundary, the redundant auxiliary feedwater
- systems, the residual heat removal
- system, and the battery room.
C.
Missile barriers which meet ore-1973 recuir ments Structures and systems impor.ant
.o safety which provide adequate protection or are ",ro:acted against the two missile impac.s in LV, above, are:
1.
C"ndensate storage tank Ze Control room 3.
All main steam line isolation valves 6
A 4.
All main steam line safety relief valves 5.
The sides of the spent fuel pool.
The licensee has confirmed that the masonry block walls which protect the control room from tornado missiles have been covered by 3/8" thick armor
. plate.
D.
Safet e ui ment not rotected b
ade uatemissile barriers The steel siding structures contain the remaining structures,
- systems, and components important to safety, i.e.,
those not mentioned in V.B or V.C, above.
These are:
1.
Component cooling system 2.
Refueling water storage tank 3.
Electrical buses 14, 17 and 18
'4.
Service water system 5.
Diesel generators and their fuel supply*~
6.
Relay room 7.
Main steam lines A and B
- In addition to being required for safe shutdown, loss of this component coulc flood the upper floor of the auxiliary building or drain to lower levels, where safety related equipment is located.
Vulnerable due to the 10' 7'orrugated sheet metal rolling door; intake and exhaust structures would be subject to damage from missile impact and collect debris.
8.
The top surface of the spent fuel pool is open and therefore the internals are exposed.
9.
Boric acid tanks~
l0.,
Main feedwater lines The ability of the steel siding surrounding these components and systems to withstand tornado wind loadings and pressure differentials is being investigated in SEP Topic III-Z.
It is expected that the siding will not be able to withstand large loadings;
- however, even if the siding remained attached to the l
s".ructural steel, its ability to withstand missile impact would be negligible.
Therefore, the only missile protection existing for the above items.
is the strength of the components themselves.
The boric acid tanks located in the auxiliary building on floor elevation 271'-0" extend to elevation 283'-0" and are protected on all sides by an 18" thick concrete wall with a top elevation of 286'-0".
Any missile striking the tanks should have to enter from above and therefore, any penetration of the tanks would most likely occur in the upoer portion.
'he acid is 12",. boric acid by weight arid would not react significantly with concrete or steel in the short amount of time these materials would be exposed to the acid before being cleaned up.
The concern regarding the boric acid tanks is flooding.
The walls have two entrances through them and therefore will not function as dike walls.
While. not required for safe
- shutdown, loss of this component could flood the upper floor of the auxil.iary building or drain to lower levels, possibly affecting equipment 1ocated there.
The licensee should provide a conservative estimate of the amount of acid which may be released
'and describe the consequences of such a release.
The licensee has provided additional information on the above structures, systems and components and are discussed below:
Component cooling water system - The licensee has stated that the reactor can be placed in a hot shutdown condition and eventually cooled to a cold shutdown without this system.
To achieve cold shutdown would require either a steam generator cold shutdown method (currently being reviewed in conjunction with fire
'protection) or repair of the CCM and would thus not be achieved for many days.
The system should remain on the list and be resolved as part of the integrated assessment after the resolution is determined for fire protection.
2.
Refueling water storage tank - The licensee has stated that the protected portion of the tank (below operating floor) is sufficient to provide make up in order to achieve cold shutdown.
Flooding still remains as a concern.
3.
Electrical buses 14, 17 and 18 - The licensee will install an additional safety related bus (14A) as part of the fire protection safe shutdown system.
This bus will be separated from bus 14 and will therefore be sufficient to eliminate the concern regarding bus 14.
Buses 17 and 18 still remain unprotected.
Main steam lines A and B - Although the licensee has said that the lines are approximately 1.4 inches thick, it has not been shown that if the lines are struck, they would be capable of maintaining their structural integrity sufficiently to resist the internal loads for both missiles postulated in SEP.
5.
6.
Surface of spent fuel pool - The effects of a one inch steel rod have been evaluated in previous analyses (e.g., staff testimony and response to interrogatories on spent fuel pool protection against tornado missiles for North Anna Units 1
and 2).
The results indicate that potential offsite radiological consequences are within 10 CFR Part 100 guidelines.
The effects of a wood.
pole entering the pool have not been evaluated.
The licensee's response provides assurance that an increase in the number of fuel assemblies does not pose an additional. risk but does not address the effects of the pole entering the pool.
Boric Acid Tanks - The licensee has stated that there would be no flooding of safety related equipment
~ven if both tanks emptied their entire contents.
Therefore, the structures, systems and components still considered to be of concern due to a tornado missile strike are:
l.
Component cooling system 2.
Refueling water storage tank 3.
Electrical buses 17, 18 4.
Service water system 5.
Diesel generators and their fuel supply 6.
Relay room 7.
Hain steam lines A and 8
8.
Top surface of the spent fuel pool 9.
Main feedwater lines VI.
CONC LUS IONS Our evaluation indicates that major portions of the systems important to safety are inadequately protected from tornado missiles.
The need for improvement of this protection will be evaluated as part of the integrated assessment for Ginna.
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Docket No. 50-244 LSO5-82<2-O77 UNITED STATES NUCLE'AR REGULATORY COMMISSION WASHINGTON, D. C. 20555 February 19, 1982 Mr. John E. Maier, Vice President Electric and Steam Production Rochester Gas E Electric Corporation 89 East Avenue Rochester, New York 14649
Dear Mr. Maier:
SUBJECT:
SYSTEMATIC EVALUATION PROGRAM TOPIC III-4.B, 'TURBINE MISSILES - R.E.
GINNA Enclosed is a copy of our final evaluation of Systematic Evaluation Program Topic III-4.B.
This evaluation incorporates comments provided to us by your letter dated February 8, 1982.
This evaluation will be a basic input to the integrated safety assessment for your facility unless you identify changes needed to reflect the as-built conditions at your facility.
This topic assessment may be revised in the future if your facility design is changed or if NRC criteria relating to this topic are modified before the integrated assessment is completed.
Sincerely,
Enclosure:
As stated Dennis M.'rutchfield, ief Operating Reactors Bra ch No.
5 Division of Licensing cc w/enclosure:
See next page
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Ginna Docket No. '50-244 Rev. 2/8/82 Mr. John E. Maier CC Harry H. Yoigt, Esquire
- LeBoeuf, Lamb, Leiby and MacRae 1333 New Hampshire Avenue, N.
W.
Suite 1100 Washington, D. C.
20036 Mr. Michael Slade 12 Trailwood Circle Rochester,
.New York 14618 Ezra Bialik Assistant. Attorney General Environmental. Protection Bureau New York State Department of Law
'2 World Trade Center New York, New York 10047 Resident Inspector R. E. Ginna Plant c/o U. S.
NRC 1503 Lake Road
- Ontario, New York 14519
- Director, Bureau of Nuclear Operations State of New York Energy Office Agency Building 2 Empire State Plaza
- Albany, New York 12223 Rochester Public Library 115 South Avenue Rochester,'ew York 14604 Supervisor of the Town of Ontario 107 Ridge Road West
- Ontario, New York 14519 Or.
Emmeth A. Luebke Atomic Safety and Licensing Board U. S. Nuclear Regulatory Commission'ashington, D. C.
20555 Dr. Richard F..Cole Atomic 'Safety and Licensing Board U. S. Nuclear Regulatory Commission Washington, D. C.
20555 U. S. Environmental. Protection Agency
~
Region II Office ATTN:
Regional Radiation Representative 26 Federal Plaza New York, New York 10007 Herbert Grossman, Esq.,
Chairman Atomic Safety and Licensing Board
~
U. S. Nuclear Regulatory Commission Washington, D. C.
20555 Ronald C. Haynes, Regional Administrator Nuclear Regulatory Commission, Region I Office of Inspection and Enforcement 631 Park Avenue King of Prussia, Pennsylvania 19406
As a result of the turbine cracking problem, Westinghouse has revised its probability analysis of damage to safety related structures, systems and components of damage to an acceptable probability.
The analysis includes utilizing the following individual probabilities:
(1) the probability of turbine failure leading to the ejection of turbine missiles.
due to desi gn speed failures and destructive overspeed failures (Pl),
(2) the probability of strike (P2) and (3) the probability of damage (P3).
Since the evaluation of the latest Westinghouse probability analyses has not been completed by the staff, criteria; considering turbine cracking and the implemented inservice inspection
- program, have not been established for determining Pl.
'The staff, upon comple-
'tion of the Westinghouse review, will determine what actions, if any, are required.
The staff determined that the licensee performs
- a. testing program for the overspeed protection system.
Specifically., there. are three different.
.tests performed on a routine basis as.follows:
At every turbine overhaul and at each refueling outage the following two tests are performed:
l.
Overspeed protective test - actually overspeed turbine to trip set point to close stop and governing v'alves.
This test is only performed during power descent and not repeated during power escalation unless problems
" " were encountered.
2.
As turbine is brought::up to speed, stop and governing valves are "tested".
as a normal part of the startup.
Every month except for the last two months of each. cycle, while the plant is operating, power is reduced and each stop and its two associated gover-nor valves are sequentially exercised.
CONCLUSION The i,nspection program committed to by RGIEE (Reference 1
and
- 2) provides.
an acceptably high degree of assurance that turbine discs will not fail at speeds up to design speed.
The testing program of the overspeed protection
- system, including the stops and control valves at Ginna provides reasonable-assurance that the overspeed protection system will remain operable
- and, thereby, limit the likelihood that overspeed past the design conditions would occur.
The staff concludes, for an interim period until a decision is reached re-garding the need for updated probabilistic analysis of the turbine missile
- hazard, the probability of damage from turbine missiles is acceptab'iy low.
Should fur ther reviews of operating plants and/or additional requirements be deemed necessary, the Ginna plant will'be.included with that operating plant action.
C 3w VII.
REFERENCES 1.
Letter from D.
M. Crutchfield (NRC) to J. Maier (RGEE),
August 28, 1981.
2.
Letter from J. Maier (RG8E) to D.
M. Crutchfield (NRC),
September 16, 1981.
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SYSTEMATIC EVALUATION PROGRAM TOPIC III-4.8 GINNA TOPIC:
III-4.8, TURBINE MISSILES INTRODUCTION
.The purpose of 'this topic is to assure that, with respect to potential turbine missiles, all structures, systems and components important to safety either have adequate protection by means of structural barriers or have an acceptably low probability of damage.
REVIEW CRITERIA 10 CFR 50, Appendix'A, GDC 4 III.
RELATED SAFETY TOPICS AND INTERFACES IV.
III-4.C, Internally Generated Missiles REVIEW GUIDELINES Standard Review Plan (SRP) Section 3,5,1.3, Regulatory Guides (R.G.)
1.115 and 1;117.
V.
EVALUATION During November 1979, the NRC staff became aware of 1ow pressure turbine disc cracking in Westimghouse turbines at several operating plants.
Additional inspections at other plants possessing'Westinghouse turbines also indicated cracking thus implying a generic problem applicable to plants with Westinghouse turbines.
Consequently, on February 25,
- 1980, the NRC issued 50.54(f) letters to utilities with Westinghouse low pressure turbines requesting information related to this problem.
Both Westinghouse and the NRC staff have been fo'llowing this problem closely and have developed independent crack growth models.
The findings of multi-plant action, 8-46, "Turbine Missiles;" concluded that an inspection schedule based on an approach developed by Westing-house for their turbine provides an acceptably high degree of assurance that discs will be inspected before cracks can grow to one-half of a size that could cause disc failure at speeds up to design sp'eed, The Rochester Gas E Electric Company (RGSE) was provided with a sa,ety evaluation report of this approach and was requested to commit to use the four criteria listed on page 3 of the safety evaluation report (Reference 1}.
RGSE responded to this request (Reference.2) and.,comitted;to the....
foui criteria.
As a result of this cosmitment an acceptably high degree of assurance is provided that disc failures at design. speed will not
'o'ccur.