ML20247R531
| ML20247R531 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 05/25/1989 |
| From: | Creel G BALTIMORE GAS & ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-88-14, NUDOCS 8906070245 | |
| Download: ML20247R531 (5) | |
Text
. _ _ _ _ _ _ _ _
e.,
1 BALTIM ORE GAS AND ELECTRIC CHARLES CENTER
- P. O. BOX 1475 BALTIMORE, MARYLAND 21203 GconGc C. CRect vier Par 5+ rat May 25,1989 NucLtam r.htnsy (301) 860-m mES U. S. Nuclear Regulatory Commission i
Washington, DC 20555 ATTENTION:
Document Control Desk
SUBJECT:
Calvert Cliffs Nuclear Power Plant Unit Nos.1 & 2; Docket Nos. 50-317 & 50-318 Response to Request for Additional Information Gener:c Letter 88-14, instrument Air Supply System Problems Affecting Safety-Related Eculoment
REFERENCE:
(a) Letter from Mr. S. A. McNeil (NRC) to Mr. G. C. Creel (BG&E),
dated April 21, 1989, same subject Gentlemen:
Reference (a) detailed questions and concerns which arose from the initial NRC staff review of our submittals of February 17 and March 10, 1989. Those submittals provided a partial response to NRC Generic Letter 88-14, dated August 8,
1988, concerning possible adverse effects of instrument air system deficiencies on safety-related equipment. Reference (a) reauested that we provide additional information in response to the detailed questions and concerns in order to clarify our responses to the generic letter. Our response to Reference (a) is provided in Enclosure (1).
Should you have any further questions regarding this matter, we will be pleased to discuss them with you.
Very truly yours,
)
J
/
//
f jt GCC/DLS/ dim Attachment fl cc:
D. A. Brune, Esquire p
J. E.
Silberg, Esquire R. A.Capra, NRC S. A.McNeil, NRC W. T. Russell, NRC H. Eichenholz/V. L. Pritchett, NRC f
T. Magette, DNR g
8906070245 890525 PDR ADOCK 05000317 P
.4 ENCLOSURE (I)
RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION GENERIC LETTER 88-14, INSTRUMENT AIR SUPPLY SYSTEM PROBLEMS ' AFFECTING SAFETY-RELATED EQUIPMENT NHCITEMl Please provide the actual instrument air quality test results previously mentioned in your March 10, 1989, letter, including particulate results, identification of any specific safety-related components for which your current instrument air qu'ality test results do not meet their manufacturer's air quality recommendations, and a discussion of why no adverse effects are posed to the operability of these specific safety-related components.
BG&EEESPONSE Our instrument air quality meets the manufacturers' recommendations for safety-related components. Manufacturers' recommendations call for clean, dry air at the component, and for providing the associated filter / regulator for the recommended particle size, (i.e.,
in our February 17, 1989, submittal, we reported that our most limiting component was a Masoneilan 8005 current to pressure converter, which required a five micron filter). We sampled our instrument air headers in three locations for each Unit; immediately downstream of our air dryer after-filters, at a point "mid-way" in the header (our Service Water Room), and at a point "far" from the supply system (one of our Diesel' Generator Rooms).
Laboratory analysis of the particulate showed that the particles per cubic foot are extremely low. Particulate were determinnd to be corrosion products as opposed to desiccant. Sample results are given below.
UNIT I UNIT 2 AFTER SRW DIESEL AFTER SRW DIESEL FILTER ROOM ROOM FILTER ROOM ROOM Particulate 4.7 5.6 3.0 2.8 1.4 1.0 Per cu. ft.
Particle Size (Microns)
Percent Size Distribution 3-5 32%
39%
63 %
62 %
35%
36%
5-15 52%
42%
26%
20%
47%
40%
15-25 13 %
13 %
6%
12%
10%
13 %
25 +
3%
6%
5%
5%
8%
12 %
Sample flowrates were all approximately 5 sefm.
Although some particulate are larger than five microns, the component filters will remove them for several y ears. Instrument air lines downstream of the filters are typically copper or stainless steel and will not contribute additional particulate.
Therefore, we have no reason to believe that air quality at any specific safety-related component does not meet the manufacturer's recommendations.
_1
ENCLOSURE (I)
RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION GENERIC LETTER 88-14 INSTRUMENT AIR SUPPLY SYSTEM PROBLEMS AFFECTING SAFETY-RELATED EQUIPMENT In our March 10, 1989, submittal, we reported that we were in the process of purchasing equipment to test instrument air onsite and we committed to report test results from that equipment as soon as they were known. That equipment arrived May 15,1989. We intend to take samples representative of air supplied to the components. These samples will be taken following vendor calibration of the equipment and vendor-provided training.
We did not have vendor particulate-per-cu.ft.
results prior to the March 10, 1989, submittal and we do not anticipate any adverse results. We would be happy to report all test results, if you wish. We prefer to only report results if they are adverse.
NRC ITEM 2 Please provide a discussion of the corrective actions taken to improve the training given to both Plant Operators and Licensed Operators on the procedure for and the effects of a loss of instrument air, for the operator knowledge deficiencies noted in NRC Examination Report No. 50-317/87-19 (OL) and 50-318/87-21 (OL). This report identified the generic deficiency that all three Reactor Operators and all five Senior Reactor Operators that were examined "were weak with respect to the fail position of various valves after a loss of instrument air header pressure."
BG&E RESPONSE Between July 1988 and March 1989, new qualification manuals, reflecting a new Operator Job and Task Analysis, were implemented. The Control Room Operator Qualification Manual contains information that applies to Reactor Operators and Senior Reactor Operators. This manual now requires candidates to evaluate the effect that a loss of Instrument Air would have on key plant systems. Numerous lesson plans are also administered in - the Plant Operator continuing, initial RO/SRO, and Licensed Operator Requalification training programs, all reinforcing fait positions as objectives.
It must be emphasized that our training programs stress the proper use' of procedures and pertinent reference material in lieu of relying on the operator's memory for safe operation of the plant.
NRC ITEM 3 Please provide details about the potential instrument air design concerns that were deleted from your February 17, 1989, submittal, as was stipulated therein.
BG&E RESPONSE Our February 17, 1989, submittal included a paragraph identifying both areas of potential concern and areas where system reliability might be enhanced. The details of those items which are potential design concerns follow:
o Emergency backup air compressor air quality was mentioned. These air compressors are powered from the emergency diesel generators. They provide a backup air supply to some key safety-related components during some emergencies. They are known as the Saltwater Air Compressors (SWAC). The SWACs are seismically designed, air-cooled, L__
J :l
's ENCLOSURE (1)
RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION GENERIC LE' ITER 88-14, INSTRUMENT AIR SUPPLY SYSTEM PROBLEMS AFFECTING, SAFETY-RELATED EQUIPMENT and oil-free. The ' SWACs do - not have air dryers downstream. Only the individual component filter or filter / regulator provides' moisture -
removal. The-SWACs are used only occasionally, for emergency purposes. 'They are the final air source after failure of - instrument air, plant air back-up, and a nitrogen supply system that is planned to be operational by the end of 1989.
o The effect of air-regulator air usage on components with accumulators when isolated on a loss of instrument air was mentioned. There are air-operated ' Salves in our Saltwater System that have accumulators and' are not supplied by the SWACs. These valves are 'used to direct saltwater through an emergency discharge path to the Chesapeake Bay should the normal path be unavailable.
These - valves have filter / regulators that use small amounts of air to operate.
Currently, upon loss of instrument air and the plant air backup, the accumulators would eventually depressurize due to the filter / regulator operation.
The nitrogen supply system will soon be operational and will provide an additional backup.
The chance of this scenario occurring are reduced by the fact that the accumulators were conservatively sized based on the number of strokes. required, plus the existence of the backup
- supplies mentioned above.
The areas in question would also be physically accessible for manual, local intervention.
o The effect on low-pressure sections of the instrument air system when air-regulators fail and allow full system pressure was mentioned.
Most of our air actuators require reduced air pressure for satisfactory operation. Some of these may maintain pressure integrity if the regulator fails, but valve damage may occur. In some cases, air line relief valves have been added to prevent actuator damage.
l This is considered an interim fix until a new actuator can be identified. The probability of air-regulator failure is considered to be low.
An additional potential concern involves radiation degradation of regulator internals and valve actuator diaphragms. Components would still fail in the safe l
direction, but operability after an accident involving a high radiation field is uncertain. In some cases, valve actuators that can withstand a high radiation field have been identified and are being installed. Evaluation of the remaining cases continues.
During testing to comply with Generic Letter 88-14, Unit I check valve IA-650 failed a back-leakage test. This check valve is a boundary check valve between I L
ENCLOSURE (1)
RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION GENERIC LETTER 88-14 INSTRUMENT AIR SUPPLY SYSTEM PROllLEMS AFFECTING' SAFETY-RELATED EQUIPMENT safety-related loads and-non-safety-related loads.
The root cause of this failure was ' the valve type being. inappropriately chosen for its intended application. The existing check valve is primarily designed to function with a higher header pressure (about 250 psig) than what. actually exists (about 100 psig). IA-650 is isolated and a valve better suited for the intended use is being sought.
NRC ITEM 4 Please provide a more precise schedule for the. specific outages during which tests of the air-operated safety-related components will be completed. The February 17, 1989, response has already led to confusion as Unit I underwent a planned outage in February - March 1989, which was after the expiration of the desired ' 180-day response time, yet the Unit I components were not tested.
BG&E RESPONSE We intend to complete all testing on Unit 2 during the ongoing refueling outage. We intend to complete all testing on Unit I during a' maintenance outage presently scheduled for 'he fall of this year.
1 i
i
.a.
l-
_ _ _ _ _ _ _ _ _ _ _ _. _ _ _ _ _ _ _ _ _ _ _ _ _ _