ML20148J240

Forwards Review & Comment on Reg Guide 1.XX,Appl of Torque Switches in Motor-Oper Valves Important to Safety. Reported Failures Could Be Resolved by Proper Maintenance & Issuance of IE Circular Instead of New Reg Guide

ML20148J240
Person / Time
Issue date:	11/03/1978
From:	Morrison W NRC OFFICE OF STANDARDS DEVELOPMENT
To:	Eisenhut D Office of Nuclear Reactor Regulation
References
RTR-REGGD-01.XXX, RTR-REGGD-1.XXX, TASK-RS-801-4 781102, NUDOCS 7811150217
Download: ML20148J240 (8)

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,, CONFIDENTIAL

'b DEPARTM ENT OF STATE f w in,ncion, o.c. 20s20 BUREAU OF OCEANS AND INTERNATIONAL ENVIRONMENTAL AND SCIENTIFIC AFFAIRS October 18, 1978 Mr. J. M. Felton Director, Division of FREEDOM OF INFORMATION l

Rules and Records ACT REQUEST Office cf Administration Nuclear Regulatory Commission ._g y /

l Washington, D.C. 20555

Dear Mr. Felton:

Au 'd 10 40 ~W The Department of State has received a request from Ms. Kehoe dated May 15, 1978, under the Freedom of Information Act for access to documents pertaining to the safety and economic feasibility of nuclear power programs in South Korea.

The Bureau of Oceans and International Environmental and Scientific Affairs has located 5 documents which origin-ated in the Nuclear Regulatory Commission and pertain to the request. Copies of these documents are enclosed and are referred to you for direct response to Ms. Kehoe.

The Bureau has advised Ms. Kehoe that we have referred the above documents to the NRC for direct response to her.

Please provide the Department FOI office and this bureau with a copy of your response to Ms. Kehoe. If you have any questions concerning this matter, please contact Roy Simpkins (632-4720) of my office.

Sincerely, ['

. Try 4 h

/' Louis V Ncisenzo Enclosure (bokYputy Assistant hecretary

1. 15 Seoul 7413 9/2/77

1. St te 3 3 1 8 UNCLASSIFIED WITHOUT

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119411 5/10/78 DOCWENTS

1. 27 129368 5/22/78 CONFIDENTIAL 7811 15 0N7

j7 UNITED STATES

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@- ~2 NUCLEAR REGULATORY COMMisslON

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..j-lj WASHINGTON, D. C. 20556

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%*****/ NOV 2 1978 MEMORANDUM FOR: W. M. Morrison, Assistant L'irector for' General Engineering Standards, Division of' Engineering Standards-FROM: D. G. Eisenhut, Acting Assistant Director for Systems and Projects Division of i0perating Reactors

SUBJECT:

REVIEW AND COMMENT.0N REGULATORY GUIOE-APPLICATION i 0F TORQUE SWITCHES IN MOTOR-0PERATED VALVES IMPORTANT TO SAFETY, DATED SEPTEMBER 7, 1978 l

(TAC 5036)

SD Task Leader: E. C. Marinos, RSSB L SD Task Number: .RS 801-4 Requested Action: Review and commerst P.equested Completion Date: September 29, 1978 Reviewing Branch: Plant Systems Branch In response to your September 12, 1978 memorandum we have reviewed

, the working paper dated September 7, 1978 of a Regulatory Guide 1

.i entitled " Application of Torque Swtiches in Motor-0perated Valves Important To Safety." We believe that the major concern with the

, reported failures have, for the most part, been the direct result

.i of improper valve maintenance'or operation, i.e. overtightening of i

, valve packing glands or excessive manual force being exercised in

the closing of these valves in order to successfu119 pass leak rate

.i tests. Therefore, it is our view that this issue can be best resolved

'! by the issuance of an I&E circular rather than by means .of a regulatory i

guide.

I i We believe that there are at present sufficient guidelines available, such as the existing criteria delineated on pages 1.XX-1 and 2 of the proposed regulatory gui,de, including the requirements for pre-  !

operational testing to assure early identification of problems that-might be encountered not only with the valves under discussion but all other safety-related motor, air, and hydraulically operated valves i in a facility. Moreover,Section XI of the ASME code requires period j testing of valves, including stroke time.

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I Our detailed comments on your working paper of the regulatory guide, f.

j along with a copy of a letter on the subject dated September 26, 1978

! to F. Clemenson from C. Formica of Limitorque Corporation are enclosed. We would be happy to meet with you to discuss these comments. ,-

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D. Eis> , ng Assistant .

Director

. for Systems and Projects '

Division of Operating Reactors p,

Contact:

c ' ?lq F. Clemenson X28077 .a

. . . Ca i s J. Burdoin X28077 . *x ,y

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Enclosures:

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[F - - CWo4WT5-UCMEUULA TORY GUI DE T. XX ' ' ~"- - ----

APPLICATION OF TORQUE SWITCHES IN MOTOR-0PERATED VALVES IMPORTANT TO SAFETY l

1. In Section B, Discussion, it is recommended that the following j sentences be reworded as follows:

a. first paragraph, second sentence. .. " Operating experience has u

shown that a variety of factors can cause the valve assembly to fail in carrying out its function"

. b. Second paragraph, second sentence..."It is therefere important

'l to (1) properly maintain the valve assembly (E) verify that the valve assembly has been returned to its normal operational status following manual handwheel valve actuation, by stroking valve with the sctuator and (3) provide for pericdic verification of the valve assembly's performance requirements.

(Note: 10 CFR 50 Appendix J III.C.1 does not permit tightening of the valve after closure by valve motor when

conducting leak tests on the valve).

i l 2. We suggest that the third paraaraph in Section B, Discussio1, be reworded as indicated below in order to make it clear that exccssive

. valve friction resulting from inadequate valve stem maintesance j or manual handwheel actuation can cause what appears to be improper operation of the torque switch controlled motor-operated valves.

"Frun a practical point of view,in oraer to limit tha number of models of torque switch actuated valve actuators a wide range of adjustments has been designed into the torque switch in order to limit the forces that may be developed by various actuators ana yet meet the forces required by various valves. A low torque switch setting may prevent i

the valve from being properly actuated while a high torque switch setting may result in an electrical overload, electrical system faults and possible damage to the valve assembly.

Assuming a normal degree of valve maintenance, the other i

variablesentering into the proper torque switch setting 1

' includes the minimum and maximum' acceptable motor voltages, i.e., the driving torque of the motor; the minir m and maximum pressure differentials that may exist across the valve when it is to be actuated and i.he valve friction, (possibly resulting from improper valve stem stuffing box maintenance and manually over torquing the valve assembly using the actuators handwheel) enter into establishing the force required to actuate the valve as well as the inertia forces developed by the valve at the end of stroke and the time delay before power to the actuator ,

is interrupted. Of the above variables, valve friction is one of the more difficult variables for the actuator vender to predict since it is a function of the plant maintenance personnel and is therefore not a readily determined quantity, o - . . , , . a.  :

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In use, it is possible to overcome an excessively high valve friction by increasing the torque switch setting. This may lead to electrical overloads and or damage to the valve ,

assembly. Likewise without corrective hetion, when high valve friction exists, the actuator may fail to properly actuate the valve."

3. In the fourth paragraph, Section B, Discussion and in Item 2.1 subsection 2.0 Section 3, Regulatory Position; it is implied that special regulated power supplies are furnished for some valve motor-coerators. We are of the opinion that regulated power supplies for valve motor-operators are seldom if ever used in nuclear power plants. We suggest that the portions of the guide which make reference to this type power supply for valve motor-l operators be rewritten to address the normal design.

4. In the fifth paragraph Section B, Discussion, the example of the .

failure of a fuse in the MOV power circuit is an example of a j seldom used design. Most of the M0V's are energized and protected l by circuit breaker / contractor combination starters, and not fused

, power circuits.

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5. In the sixth paragraph, Section B, Discussion, it is our opinion that this paragraph is not germane to the concern and can be left out. Deterioration of cable, if any, resulting from momentary heating caused by overcurrent for short periods of time or due to voltage imbalance need not be addressed in this guide.

6. In the seventh paragraph, Section B, DW:ussion, it is felt that the use of the example, compatible design of motor-operator and valve is inappropriate unless it is intended to suggest that the designers are making mistakes based on lack of understanding.

7. The following comments apply to Section C, Regulatory Position' ,

Item 1.1; we suggest this item be rewritten as follows:

" Provisions should be made to allow for periodic actuation of the valves, under ,similar flow and pressure conditions to those expected when the valvc is called upon to perform its safety function."

Item 1.2 The last sentence of this item is ambiguous. The '

thought you are attempting to c myey is not clear.

Item 2.1, 2.2 and 2.3 can be consolidated by the following para-graph:

"For valves whose motor operators are designed to deliver required torque at nominal voltage of either offsite or onsite power sources, the tests described in position 4.0 should be condacted separately for both power sources."

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j Item 3.2 The words " voltage balance" should be replaced with the words " voltage level" or " voltage magnitude."

( Item 3.3 This item needs additional clarification. It should address the following questions. How is position indication to be provided? Is the position indication to operate only at the limits of valve travel or is it to indicate interruption anywhere between the limits of travel?

Item 4.1 This testing is presently required under surveillance testing of ECCS in the technical specifications.

I Therefore, this item does not have to be all-inclusive but nied only include the M0V being tested.

Items 4.2 and 4.3 are concerns that seem inappropriate in a regulatory guide. Therefore, it is suggested that the guide recommend that items 4.2 and 4.3 be included in M0V test procedures.

Item 4.2.1 We suggest this item be rewritten as follows:

"The valve stem frictional forces are not excessive."

8. Enclosed is a copy of the subject regulatory guide, marked to bring to your attention certain typographic errors found during our review.

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