ML20072A862

Requests Response to Previous Correspondence Opposing OPS Floating Nuclear Power Plants,Heretofore Unacknowledged by Nrc.June 1976 Testimony on SER Encl

ML20072A862
Person / Time
Site:	Atlantic Nuclear Power Plant
Issue date:	12/12/1982
From:	Effenberger E AFFILIATION NOT ASSIGNED
To:	Palladino N NRC COMMISSION (OCM)
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ML20072A856	List: ML20072A862 ML20072A867 ML20072A870 ML20072A876
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NUDOCS 8301240207
Download: ML20072A862 (11)

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3 Decembe r 12, 1982 Ernst J. Effenberger P. O. Por 16071 Jacksonville, P1 32245 Mr. Nunzio Palladino Chairman Nuclear Regulatory Commission Washington, D. C. 20555 Ref. No.: STN 50-437 Floating Nuclear Power Plants Sir:

Please find enclosed copies of the previous correspond-ence on which I have not received an answer.

My concern is sincere, my technical reasons are more than valid. But you, as the repesentative of the N. R. C.

find it not necessary to give me the benefit of a doubt or the courtesy of an answer.

Sincerely, Ernst J. Effenberger Encl.: Testimony (June 1976)

Le tter 1-29-1982 Letter 8-14-1982. .

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• Letter 12-1-1982 Letter 12-6-1982 News Clipping Copies to Commissioners:

Mr. James Roberts Mr. James Asseitine Mr. Victor Gilinsky Mr. Jonn Ahearne News Media O

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PDR ADOCK 05000437 A PDR.

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' JUNE 1976 i

COMMENTS ON THE SAFETY EVALUATION REPORT NUREG -75/100 (9/30/75)

AND SUPPLEMENT NUREG -0054 (3/16/76)

BY THE OFFICE OF NUCLEAR REACTOR REGULATION UNITED STATES NUCLEAR REGULATORY COMMISSION RELATED TO THE PROPOSED MANUFACTURING OF FLOATING NUCLEAR POWER PLANTS OFFSHORE POWER SYS,TEMS DOCKET NO. STN 50-437 SAFETY EVALUATION OF MECHANICAL EQUIPMENT COMMENTS BY ERNST J. EFFENBERGER, A CONCERNED U. S. CITIZEN

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INTRODUCTION My name LS Ernst J. Ef fenberger. I am a concerned U. S. citizen, a mechanical engineer having thirty years of professional experience in steam turbines, gas turbines, waste heat recovery, chemical refineries, fossil and nuclear power plants. (My personal history record is available if requested).

The basis for my comments are the Plant Design Report of Offshore Power Systems (PDR) including Amendment #22 and NRC'S Safety Evaluation Report (SER) and its Supplement.

Many concerna, objections and fears concerning nuclear power plants have been raised by responsible citizens of this country. Following up on the development of nuclear power plants and the floating nuclear plants (FNP) in particular, I have seen very little technical development and evaluation on the feasibility of these projects. Engineers in general are afraid to think or to talk and are afraid of losing their jobs. In spite of this, let me give you my thoughts or. the subject.

My concern is the safety of tre public. I will restrict my comments at this time to the larges and most dangerous piece of equipment on the FNP, the turbine generator. (T-G) .

If the T-G should go on the destructive overspeed, then the largest piece ejecting the turbine casing will have a kinetic energy of 32 million ft. lbs. There is nothing on the present FNP which could contain or stop these missiles which in turn would penetrate all the structures, the shield building, the containment and the reactor vessel itself and in addition would puncture the null and sink the plant. What happens then, I will leave to your unagination.

SER Supplement, page #19, quote:"we conclude that it is feasible to design and install a turbine generator foIndation system which will function on the platform."

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.s I shall show and prova it is technically not feasible to maka the present design work without sacrificing safety. The present design will increase the turbine missile probability to an extent where it is questionable to go ahead with the FNP, because the state of the art has no proof,nor solution for a satisfactory and safe operation under the platform motion criteria.

COMMENTS

1) NRC, Bush Report 4/7-1973, Probability of T-G Missiles.

This report does collect data on a worldwide basis of T-G failures. Not a single floating T-G is included, just information on land based units. Therefore, this report is totally unacceptable for an evaluation. There is no comparison between a land based T-G and a floating T-G. A land based unit is erected and operated on its natural " sagging line." The slightest deviation from this line will cause an unrest of the rotor which will show up in excess vibration until the misalignment is corrected. Every T-G in the world operates that way. No j other situation is known.

t The conclusion in the Bush Report shows that a probable 4

failure of a T-G is in the range of 10 . To be on the safe f 7 side, the NRC assumed a 10- failure rate on new land based nuclear power plants is sufficient to guarantee the safety of the public. Ignoring the fact that the operation and environmental conditions of a floating nuclear power plant is totally different from land based plants, this requirement was also imposed on the FNP. The FNP was and is evaluated 1

as any other land based power plant and this is wrong and dangerous g because the probability of a T-G failure on the FNP is greater than on a land based plant.

2) Missile generation - A standard land based T-G rotor is well over designed. The rotor stresses are in the range of 8 to 10 times the safety factor, because the bearing diameter usually dictates the other dimensions of the rotor.

The manufacturer of the FNP turbine assumes a i 1/2 inch deflection allowance in the operation of the turbine rotors.

This in turn will increase the bending stresses in the rotor to an extent where the safety factors in certain areas will be reduced to less than 2, which will increase the probability of a rotor failure in the same ratio, Missile generation depends on the reliability of failsafe equipment, like an overspeed protective trip system, reliability of valve system, rotor failures - material integrity, disc failures - material integrity, valve testing, just to mention a few. The orien-tation of the T-G in a power plant should be decided considering all the above conditions.

OVERSPEED TRIP SYSTEM Three overspeed protective systems are provided in this design, but all systems act finally on the same valve spindle, so no matter how many systems are installed for overspeed protection, if the one valve gets stuck then there is little protection and the reasoning for having three systems is not valid.

This The trip systems are part hydraulic and part mechanical.

means that the valves are spring loaded and the springs are kept open by hydraulic pressure. On impulse,the fluid is dumped and the springs are closing the valves. Two systems have the same drain line and any bending or plug-up of this line will make the main steam valves inoperable.

SER Chapter 10.2 states and I quote, ". . .overspeed protection system will provide assurance that destructive overspeeds of the turbine should not occur..." Now that is a technical evaluation.

RELIABILITY OF VALVE SYSTEM Turbine main steam valve stems build up deposits no matter how the feedwater is treated. Practice has shown that even valve testing is Only not practical because the schedule is never kept by the operator.

If those who have worked in and maintained a power plant know that.

every stuck valve would be reported by the utility industry, the insurance rates would go up to the extent that we would have no power stations in operation.

ROTOR FAILURES all kindsof investigations SER, Chapter 3.4.3, page #49, states on turbine disc failures, but nothing on the rotor itself, except decreasing the safety factors on the rotor as mentioned earlier. The increase in disc stresses due to plant motions are discussed,but what about rotor stresses? Since the plant motions are not kept away from the turbine shaft, the rotor will go through its own cyclic stresses, plus all the plant motions.

To illustrate the plant motions, a wave motion period of 20 seconds is assumed. Over a forty year life span, the rotor will experience over 60 million additional stress cycles. This fact is totally ignored.

The T-G manufacturer claims that no T-G failure in his design has

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occurred. I would like to point out that Shippingport, a nuclear power plant, failed at operating speed last year, not at design or if destructive overspeed;jjust fell apart after sixteen years of normal operation. Obviously the integrity of the material is only good for a limited time, definitchr not for forty years as this FNP is planned to operate.

VALVE TESTING Every valve testing makes it necessary to reduce the load of-the turbine to the point where the valve can be taken out of service to close. Having twenty main steam valves and numerous non-return valves on a 1200 MW unit, the time element involved will be such that the unit will never get above 75 - 80% of full load. This means that the utility owner will resist,and if necessary will come up with his own schedule for valve testing. This will further increase the probability of a valve failure and create a potential possibility for any overspeed condition.

RELIABILITY OF VALVE SYSTEM All three emergency trip systems depend finally on the reliability of a singic valve as shown earlier. Is this really enough? It has not been investigated what the platform motion could do to a valve spindle clearance. The stemmchest which houses the main steam valves is also exposed to the paltform motions. Valve testing is not the answer.

ORIENTATION OF TIIE T-G The NRC ikt its wisdom decided in a last year's ruling to locate the main T-G radial to the containment in any future nuclear power plants.

The main reason was the probability of turbine missiles hitting the containment and all the shortcomings discussed earlier. The rest of the

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, world has done this for many years, and this makes sense. A special exception was made for Offshore Power Systems. Why? Since the probabilities of turbine failures on a FNP are greater than on land based plants, it is an absolute necessity, for our protection, to relocate the most dangerous equipment and largestmissile producer, so as to reduce the probability of missiles. Knowingly making a wrong decision or ignorance could endanger our public safety.

BENDING OF A TURBINE SHAFT As discussed earlier, the smooth operation of a turbine shaft depends on an exact alignment of the whole turbine. Any deviation, experience shows about 15 mils, will induce excessive vibration and therefore increase the possibility of a rotor failure.

Going back to the proposed 1/2 inch deflection of the turbine shaft, history has shown that it is possible to force a rotor to operate away from the natural " sagging line". This is strictly a stress problem in the rotor coupling and the shaft ends. Increasing the coupling size and the coupling bolts usually takes care of this condition. The specific bearing pressure will also increase and this dictates a larger bearing. These changes create no problem since the operation under this arrangement is the same as in any other design. In other word 5, a turbine rotor can be designed to operate at any different point or line as long as the rotor stresses are being taken care of. Operating experience has shown all over the world that any deviation from the calculated " sagging line" will cause excessive vibration. No turbine in the whole world is known to operate under any other condition.

BEARING PRESSURE The journal bearings of a turbine rotor are very precise. The weight of the rotor dictates the size of the bearing, the thickness

, of the oil film and the oil pressura. The gap between ths betring cnd the shaft is filled with oil and well defined. If this gap is too large, the phenomena of an oil whip shows up. If the gap is too small, then the oil will be overheated and the babbit in the bearing melts. The limitations between these two conditions are very small.

Any bending of a turbine shaft during- operation will change the gap in the bearing, will change the bearing pressure and will cause all the conditions as discussed above.

SELECTIVE ALIGNMENT OF THE T-G It is impossible to compensate life loads such as vacuum loads by selective alignment. In a conventional design the condenser is fixed, the turbine is on the foundation and between the turbine and condenser is a flexible expansion joint. The full vacuum load is on the turbine.

The only way to eliminate the vacuum load is to mount the condenser on springs and eliminate the expansion joint. This arrangement works on a land based plant, not on a floating nuclear power plant, becauue there is no way to restrain the hanging condenser, which is also exposed to the platform motions.

The statement in SER Supplement, page #19 under 10.2.1 is wrong, premature and unrealistic. "We conclude that it is feasible to design and install a turbine generator foundation system which will function properly on the platform."

It seems to me that everything was done to weaken, to neglect,to ignore, to go away from good engineering practice and experience in designing the FNP.

Let me sumarize Bending the shaft during operation is against any experience history and totally unproven.

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Redt'cing the stress safety factors in the shaft from 8 - 10 down to below 2 is increasing the possibility of a shaft failure and a missile generation.

Changing the bearing pressure during operation will induce vibration and increase the possibility of a shaft failure and missile generation.

The overspeed protective trip systems are acting on the same valve spindle and therefore not reducing the overspeed possibility. Two of the three emergency trip systems have the same dump lines. Any damage or plug-up of this line will increase the possibility of an overspeed condition and therefore missile gener-ation.

Hull vibrations will add to rotor strains and stresses and increase rotor failures and therefore missile gene.ations.

I fail to see that the applicant has proven to show that it is feasible to design and install a turbine generator - turbine foundation system on the platform; therefore I state that the FNP in its present design is not safe, not reliable, dangerous and the manufacturing license should be withheld until proven otherwise. This present project is not in the interest of the public safety, nor our environment, nor is it in the interest of our children.

At this point, I would like to quote the concluding paragraph from a letter from Mr. W. Kerr to Mr. W. A. Anders, dated December 10, 1975.

"The Advisory Committee on Reactor Safeguards believes that subject to the foregoing and other applicable matters discussed in its reports of November 15, 1972 and October 18, 1973, the

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floating nuclear plant unit can'be constructed with reasonable assurance that they can be operated without undue risk to the health and safety of the public."

I fail to see how the NRC can honestly say that it is feasible to build the proposed FNP. There are many unsolved technical problems, there are more problems than answers and the NRC still continues to talk about the feasibility of a FNP.

May I suggest that the NRC take a closer look at the other design of a FNP by a competitor of Offshore Power Systems and then come up with a conclusion.

I request that the NRC answer all my questions and give the reasons for the decisions they made. Since this is a public issue, all of our health and well being is involved. I expect an answer before any other decisions are made.

Gentlemen, this concludes my thoughts on only one piece of mechanical equipment on the proposed FNP. I intend to comment on every piece of equipment on the FNP, because I believe that the design and arrangement are made against any good engineering principle, judgement or experience.

Thank you.

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