ML20082J913

Submits Response to NRC Request for Addl Info Re Amend to Facility Operating License on Surveillance Frequency Requirement for Testing of Emergency Battery

ML20082J913
Person / Time
Site:	MIT Nuclear Research Reactor
Issue date:	04/10/1995
From:	Bernard J, Lau E, Newton T MASSACHUSETTS INSTITUTE OF TECHNOLOGY, CAMBRIDGE
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9504180498
Download: ML20082J913 (4)

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L I NUCLEAR REACTOR LABORATORY .

AN INTERDEPARTMENTAL CENTER OF W MASSACHUSETTS INSTITUTE OF TECHNOLOGY O. K. HARLING 138 Albany Street, Cambridge, Mass. 02139-4296 J. A. BERNARD, JR.

Dkector Telefax No. (617) 253-7300 Director of Reactor Operations Telex No. 92-1473-MIT-CAM Tel.No.(617) 253 4211/4202 April 10,1995 l U.S. Nuclear Regulatory Commission l Washington, D.C. 20555 l Attn: Document Control Desk

Subject:

Response to NRC Request for Additional Information Regarding l Amendment to Facility Operating License No. R-37, Docket No. 50-20, on " Surveillance Frequency Requirement for Testing of the Emergency Battery" l 1

Gentlemen: 1 The Massachusetts Institute of Technology (MIT) hereby submits this letter in  !

response to the NRC Request for Additional Information dated March 13,1995, regarding the application (dated February 22,1995) to amend MITR Technical Specification #4.3.5 of i Facility Operating License No. R-37.

On January 13,1995, the MIT Research Reac*or replaced the entire emergency battery bank. As part of the installation and operating instructions (see attachment), the manufacturer lists a range of battery maintenance inspections and their recommended frequencies. At the MITR, the status of the emergency battery bank is checked daily as ptrt of procedure PM 3.5, " Daily Surveillance Check," and the majority of the inspection items listed in the manufacturer's manual are verified, although not documented unless anomalies are noted. The emergency battery bank voltage, the general appeaiance and cleanliness of the battery / battery rack / battery area, the battery charger, pilot cell electrolyte temperature, ambient temperature and condition of ventilation equipment in the emergency battery room, are all checked. However, only the battery bank voltage and condition of the ventilation equipment are documented as part of this daily surveillance procedure. The majority of these recommended inspection items do not have an immediate safety significance and therefore we do not feel it to be appropriate to document all of them, let alone to incorporate them into a formal MITR Technical Specification.

We believe that the MITR Technical Specifications should only include those inspection items which are essential to ensuring the operability of the emergency battery bank. Several approaches have been considered. For example, one could, as per the manufacturer's recommendations, measure the specific gravity and voltage of each cell quarterly. The drawback to this approach is that it could result in significant instances of acid spills, because there are sixty individual battery cells in the MITR emergency battery bank and that could amount to at least 240 occasions when battery acid is handled per year.

An alternative to this, which was the approach proposed in our submittal of February 22, 1995,is that (a) the voltage and specific gravity of the pilot cell (the one determined lowest in specific gravity during the annual inspection test) be measured on a monthly basis, (b) the emergency power transfer test be performed quarterly to evaluate the integral operability of the reactor's emergency battery bank system, and (c) the emergency battery discharge test be performed annually. As part of this last test the specific gravity and voltage of each cell is measured. This approach has the advantage of verifying the operability of the entire system.

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Our evaluation is that such an approach represents a better means for verifying system operability than the manufacturer's recommended frequency of inspections. Those f recommendations do not consider the availability of options such as the MITR quarterly transfer and annual discharge tests of the emergency battery system.

-We recognize the concems raised by NRC to the effect that the specific gravity of all ,

I batteries should be checked quarterly as per the manufactun:r's recommendation.' However, we would point out that the existing Specification already requires that the specific gravity of - y the .j all cells wording proposed be measured if a significant for Technical Specification change is observed

1. 4.3.5 in Appendix in theOperat A of Facility pilot cell. Specifically,j License No. R-37 is as follows: i i i

5. The voltage of the emergency batteries shall be measured weekly whenever the reactor is scheduled to operate any day of that week. The voltage and--

specific gravity of one cell shall be measured monthly whenever the reactor is scheduled to operate any day of that month.' Snecific gravity of all batteries shall be measured auarteriv' at any time a sienificant channe is - -

noted in the oilot cell and at least everv two vears. Discharge tests shall bc 1

. performed once every two years. Operability of the inverter motor generator set and associated switches sha'.1 be verified quarterly.

For your convenience, we have ' underlined the sentence that requires the measurement of specific gravity of all cells. A remaining issue is the definition of the word "significant." We define this in procedure PM 3.5, " Daily Surveillance Check" to be a reading that is outside the range of 1.205-1.245. This range was selected based on the  !

i manufacturer's recommendation.

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Please note that the MITR has approved test and calibration procedures for the  ;

quarterly transfer and annual discharge tests of the emergency battery system. These are PM 6.1.3.11, " Emergency Power Transfer Test" and PM 6.1.3.10,' " Emergency Battery Discharge Test" respectively. As part of the latter procedure, the specific gravity and voltage of each cell are documented annually.

Sin rely,

, Q homas H. Newton, Jr., PE Edward S. Lau, E Asst. Superintendent for Engineering Asst. Superintendent for Operations MIT Research Reactor MIT Research Reactor i tk Qb ohn A. Bernard, Ph.D.

Director of Reactor Operations  !

MIT Research Reactor j EI/gw l

Attachment:

Page 5, item 6, Installation and Operating Instructions for C&D Batteries cc: MITRSC (with attachment)  ;

USNRC- Senior Project Manager, l NRR/ONDD i USNRC- Region I - Project Scientist, Effluents Radiation Protection Section (ERPS)

FRSSB/DRSS

& RS-966 CHARTER POWER SYSTEMS

• CONDENSED INSTALLATION AND I

OPERATING INSTRUCTIONS l C&D STANDBY BATTERIES (FLOODED)

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l NOTE: This manual is a condensed version of installation f and operation instructions. For specific instructions,

the user must consult 12-800, Standby Battery, Flooded Cell, Installation and Operating Instructions, which is packed with the battery.

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6. M AINTENANCE

! Proper maintenance will prolong the life of a battery Operational characteristics j cnd will aid in ensuring it is capable of satisfying its Battery performance is rated at 77F (250). Operation l design requirements. A good battery maintenance program will serve as a valuable aid in determining the at higher temperature willincrease capacity but reduces life approximately 50 percent for every 15F need for battery replacement. (-9C) rise. Operation at lower temperatures reduces Monthly battery inspection should include the following: capacity but extends life. J o charge voltage measured at battery terminal During the last half of the battery service life, capacity

• general appearance and cleanliness of battery, will begin to fall slowly at first, then with increasing battery rack and battery area rapidity. Lead-acid batteries have reached the end of i

, o charger output current and voltage their useful life when capacity has fallen to 80 percent l

• electrolyte levels of published ratings. )

o cracks m the cell container or leakage of electrolyte NOTE: Frequent charge / discharge cycles accelerate o any evidence of corrosion at terminals, connectors capacity degradation.

or racks e ambient temperature and condition of ventilation To insure adequate performance it is recommended a equipment battery be sized with additional margin for operation '

• pilot-cell voltage, specific gravity and electrolyte at minimum expected temperature and for loss of temperature capacity as the battery ages. ,

o recorded findings with cleef, dated copies l Quarterly battery inspection should include: Environmental requirements '

e specific gravity of each cell Recommended operating temperature: 60F (15C) o voltage of each cell and battery terminal voltage minimum,90F (32C) maximum; 77F (25C) yearly

• temperatures of electrolyte in representative cell average Annual battery inspection should include the following: Operating temperature limits: 32F (OC) minimum, 120F (490) maximum; pressure = atmospheric o dttailed inspection of the appearance of the battery o integrity of the battery rack Ventilation: Flooded lead-acid batteries generate

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• intercell/interunit connection integrity explosive gas (hydrogen), which is vented to the l

• recorded findings with clear, dated copies environment. Although normal ventilation is sufficient

! for dispersion, accumulation must be limited to 2 NOTE: If the battery has experienced an abnormal percent or less of room volume.

condition, such as severe diccharge or over-charge, an inspection should be made to NOTE: This manualis a condensed version of installa-

! ensure the battey has not been damaged. tion and operation instructions. For specific

, instructions, the user must consult 12-800,

! Periodic inspections, as outlined above, and the Standby Battery, Flooded Cell, Installation subsequent corrective actions are intended to provide and Operating Instructions, which is packed a properly maintained battery that will meet its with the battery.

performance requirements. In addition, yearly perfor-l mance tests can be used to demonstrate the adequacy

( of the maintenance practices. Each of these inspec-l tions and tests should be used as best suited for the l particular needs of the application. It is the user's

! responsibility to format a maintenance inspection and testing program to optimize the benefit available.

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