ML19253B771
| ML19253B771 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 09/10/1979 |
| From: | Counsil W NORTHEAST UTILITIES |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| NUDOCS 7910220222 | |
| Download: ML19253B771 (15) | |
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,y, m o September 10, 1979 Docket Nos. 50-245 50-336 Mr. Boyc:: H. Grier, Director Region I Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406 Reference (1)
B. H. Grier letter to W. G. Counsil dated July 11, 1979 forwarding I&E Bulletin No. 79-15.
Gentlemen:
Millstone Nuclear Power Station, Unit Nos.1 and 2 Deep Draft Pump Deficiencies I&E Bulletin No. 79-15, Reference (1), requested that Northeast Nuclear Energy Company (NNECO) identify any deep draft pumps at either Millstone Unit No. 1 or Millstone Unit No. 2 which are similar to those described in Reference (1) and provide specific information with regard to those pumps.
The NRC Staf f requested that this information be provided within 60 days of the date of Reference (1).
Accordingly, NNECO hereby provides the attached (Attachment (1) for Millstone Unit No.1; and Attachment (2) for Millstone Unit No. 2) information in response to the NRC Staff requests.
In addition, Refererace (1) requested that NNECO accumulate and make available for inspection at the Millstone Nuclear Power Station site other specific items of information with regard to the identified pumps. All documentation requested is presently available at the plant sites, with one exceptio,. No comparison of replacement frequency with manufacturers' rated life for v tring surfaces was performed. Rated life was not specified in the design s: ecifications or by the manufacturers.
4 1149 094 7910220 NL
. In addition, all safety-related pumps at the Millstone Nuclear Power Station are presently being inspected and tested under the provisions of ASME Section XI, Subsection IWP within the Millstone ISI/IST Program.
NNECO trusts that this information is responsive to NRC Staff requests.
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY
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W. G. Counsil '
Vice President Attachment 1149 095
DOCKET NO. 50-245 ATTACHMENT (1)
MILLSTONE NUCLEAR POWER STATION, UNIT NO. 1 RESPONSE TO I&E BULLETIN NO. 79-15 1149 096 SEPTEMBER, 1979
MILLSTONE UNIT NO. 1 1.
Millstone Unit No. 1 utilizes a total of nine deep draft pumps in safety related applications.
Six are similar to the one shown in Figure 1 and three are similar to the one shown in Figure 2 of Reference 1.
2.
(a)
Four (4) service wa ter pumps provide station service water, during normal operation, to safety and nonsa fe t y related heat cxchangers.
Two (2) of the pumps are safety related and provide station service water to safety related heat exchangers during loss of normal power, The pumps were manufactured by Worthington Corporation, Model No. 16-QL-20A, and have a design point of 10,000 gpm at 180 ft. TDH.
The safety related pump mark numbers are M4-7C and P4-7D.
(b)
Four (4) emergency service water pumps provide cooling water to the low pressure core injection system heat exchangers during accident conditions.
Tbe pumps were manufactured by Worthington Corporation, Hodel No. 15-4-277-5, and have a design point of 2500 gpm at 500 ft. TDH.
Their mark numbers are M4-13A, M4-13B, M4-13C, and ?!4 - 13 D.
(c)
Three (3) condensate pumps take suction from the condenser hotwell and discharge, through various components, to the condensate booster pump suction.
The pumps were manufactured by Ingersoll-Rand, Model No. 32-AP09-3, and have a design point of 8000 gpm at 375 ft. TDH.
The pump mark numbers are M2-6A, M2-6B, and M2-6C.
3.
(a)
The Service wa ter pump columns a a twenty-four feet zero inches (24'0") long and eighteen inches (18 ")
in diameter.
The above grade discharge is twenty inches (20").
(b)
The emergency service water pump columns are twenty-three feet zero inches (23'0") long and twelve inches (12") in diameter.
The above grade discharge is ten inches (10 ").
(c)
The condensate pump columns are nine feet s i a-inches (9 ' 6 ")
long and Earty-six 2nches (4 6 ")
in diameter.
The abavo grade suction and discharge are thirty inches ( 3 0 ")
and eighteen inches (18"), respectively.
4.
General:
Service Water Pumps, Emergency Service Water Pumps, Condensate Pumps (a)
Storage and installation were performed in accordance with manur'accurer's instructions.
(b)
No significant alignment problems occurred.
(c)
Startup testing did not reveal any significant problems.
1149 097
MILLSTONE UNIT NO. 1 Specific:
Service Water Pump M4-7C (a)
Pump startup:
July 1969.
(b)
In November 1973, the pump upper seal ring was replaced.
(c)
In October 1974, the bearings were replaced.
This is in addition to the items listed in S (a ) for M4-7c.
(d)
In October 1975, the pump was inspected and returned to service.
(e)
The pump lower shaft and bearings were replaced in June 1979.
Service Water Pump M4-7D (a)
Famp startup:
July 1969.
(b)
In Decen*>cr 1971, the motor wa s cleaned, inspected, and r e t t:rned to service.
(c)
The impeller clearance was readjusted in March 1973.
(d)
In September 1973, the bearings were replaced.
This is in addition to the items listed in 5(a) for M4-7D.
(e)
In November 1976, the bearings were replaced.
This is in addition to the items listed in 5(c) for M4-7D.
Emergency Service Water Pump M4-13A (a)
Pump startup:
March 1970.
(b)
Suction bowl and impeller cleanances were set in September 1971.
(c)
In January 1972, the pump was inspected and returned to service.
(d)
In February 1973, the bearings and impeller bushings were replaced.
(e)
The lower bearing, intermediate line shaft, and shaft couplings, were replaced in June 1979.
1149 098
MILLSTONE UNIT NO.
1 Emergency Service Wa ter Pump M4-13B (a)
Pump startup:
March 1970.
(b)
Suction bo wl and impeller clearances were set in September 1971.
(c)
In January 1972, the pump was inspected and returned to service.
s'd)
In February 1973, the pump was inspected and returned to s er vi ce.
(e)
In October 1974, the shaft was reworked in the packing area.
(f)
New bearings and seals were installed in Harch 1977.
This is in addition to the items listed in 5(a) for H4-13B.
(g)
In April 1978, the shaft was reworked in the packing area, and suction bowl and impeller clearances checked.
(h)
The pump was inspected and returned to service in June 1979.
Emergency Service Water Pump M4-13C (a)
Pump startup:
March 1970.
(b)
Suction bowl and impeller clearances were set in September 1971.
(c)
In January 1972, the pump was inspected and returned to service.
(d)
Ira rebruary 1973, the pump was inspected and returned to service.
(e)
Bearings were replaced in April 1974.
(f)
Bearings were replaced in April 1977.
(g)
In November 1977, the pump was inspected and returned to s er vi ce.
Emergency Service Water Pump M4-13D (a)
Pump startup:
March 1970.
(b)
Suction bo wl and impeller clearances were set in September 1971.
i149 099
MILLSTONE UNIT NO. 1 (c)
In January 1972, the pump was inspected and returned to s e r vi ce,
(d)
In February 1973, the pump was inspected and returned to service.
(e)
In November 1977, the pump was inspected and returned to service.
Condensate Pump M2-6A (a)
Pump startup:
July 1970.
(b)
In May 1973, the pump was inspected and returned to service.
(c)
The notor lubrica ting oil was replaced in March 1978.
Condensate Pump M2-6B (a)
Pump startup:
July 1970.
(b)
The motor lubricating oil was replaced in March 1978.
Condensate Pump M2-6C (a)
Pump startup:
July 1970.
(b)
In June 1973, the pump underwent normal overhaul.
(c)
In November 1976, the pump was inspected and returned to service.
(d)
The motor lubricating oil was replaced i.) March 1978.
(c)
In June 1979, the pump underwent normal overhaul.
5.
Service Water Pumps General:
In 1974 crosion was found in the vicinity of sevezal throttling val ves.
In order to reduce the velocity through each valve, the pump impellers were trimmed in October 1974 to lower TDH to 120 ft.
This allows the valve to pass the required flow and throttle in a more open position at a reduced velocity.
1149 100
MILLSTONE UNIT NO. 1 Specific:
M4-7C (a)
In addition to the impeller trim outlined above, the volute was replaced.
(b)
In June 1975, the carbon steel enclosing tube failed and was replaced wi th one of stainless steel.
Since the failure was attributed to excessive vibra tion, a spider support was added midway along the column.
In addition, the volute and diffuser were replaced with Ni-Resist.
(c)
In January 1976, seal water was lost.
The lower and intermediate shafts and bearings were replaced.
(d)
In April 1977, seal wa ter was lost.
The lower and intermediate shafts, bearings, and one (1) wear ring were replaced.
M4-7D (a)
In September 1973, tha diffuser exhibited excessive erosion / corrosion and was replaced.
(b)
In June 1975, a spider support identical to M4-7C was installed.
Also, the discharge head was replaced due to a thin wall casting.
(2)
In November 1976 the volute and diffuser were replaced wi th Ni-Resis t.
In addition, a new suction bell, intermediate shaft, sutffing box, and stainless steel enclosing tube were installed.
(d)
In June 1979 the upper column exhi bi t ed excessive erosion /
corrosion along the longitudinal weld.
Both columns were replaced with a seamless design.
Emergency Service Water Pump M4-13A (a)
No operational problems or major maintenance.
Emergency Service Water Pump M4-13B (a)
In March 1977, the discharge hea d was replaced due to a thin wall casting.
1149 101
MIL LS TO NE UNIT NO. 1 Emergency Service Water Pump M4-13C (a)
No operational problems or major maintenance.
Emergency Service Water Pump M4-13D (a)
No operational probicms or major maintenance.
Condensate Pump M2-6A (a)
No operational problems or major maintenance.
Condensate Pump M2-6B (a)
In April 1973 the lower bearing support strut fa tigue failed and was replaced along with the suction head and lower bearing.
Condensato Pump M2-6C (a)
In May 1973, the lower bearing was replaced.
(b)
In August 1977, the stuffing box bearing seized to the shaft and was replaced with a completc rotating assembly.
6.
(a)
The longest interval that each pump has been a va il a bl e for operation without corrective maintenance:
Service Water Pumps:
M4-7C approximately: May 1977 to Present.
M4-7D approxima tel y December 1976 to May 1979.
Emergency Service Water Pumps:
M4-13A approximately March 1970 to Present.
M4-13B approximately March 1970 to Present.
M4-13C approximately March 1970 to Present.
M4-13D approxi ma tel y March 1970 to Prcsont.
Condensate Pumps:
M2-6A approxima tel y Jul y 1970 to Present.
M2-6B approximately April 1973 to Prcsont.
M2-6C approxima tel y May 1973 to August 1977.
MILLSTONE UNIT NO. 1 (b)
Identify the number of cycles of operation during this interval.
(c)
The duration of cach cycle and the operating modois).
Response to (b) and (c) cannot be cbtained.
The cyclic operation of pumps is dictated by seasonal changes and plant operating modes.
Detailed records of pump cycles are not maintained.
( d)
Identify the longest continuous operation at or near rated fl o w conditions for each pump and status of the pump operability at the cnd of the run.
Service Wa ter Pumps:
Mark No.
Operation (Hours)
Status M4-7C Approximately 10,975 Item 5 K4-7D Approximatclj 14,422 Item 5 Emergency Service Water Pumps:
Mark No.
Operation (Hours)
Status M4-13A Approximately 16 Item 5 M4-13B Approximately 688 Item 5 M4-13C Approximately 16 Item 5 M4-13D Approximately 688 Item 5 Condensate Pumps:
Mark No.
Operation (Hour 3)
Sta tus M2-6A Approxima tel y 56,720 Item 5 M2-6B Approximately 42,990 Item 5 M2-6C Approximately 14,345 Item 5 o
1149 103
DOCKET No. 50-336 ATTACIDfENT (2)
MILLSTONE NUCLEAR POWER STATION, UNIT NO. 2 RESPONSE TO I&E BULLETIN NO. /9-15 1149 104 SEPTEMBER, 1979
MILLSTONE UNIT NO.
2 1.
Millstone Unit No. 2 utilizes three (3) deep draf t pumps in safety related applications similar to the one shown in Figure 1 of Reference 1.
2.
The pumps were manufactured by Babcock & Wilcox, Canada, Ltd.,
Model No. V2650-40, and have a design point of 12,000 gym at one hundred (100) feet TDH.
The pumps provide normal and emer-gency station service water to safety and nonsafety related heat exchangers.
The pump mark numbers are 2-SW-PSA, 2-SU-p5B, and 2-SW-PSC.
3.
The pump columns are thirty feet ten and one-half inches (30'104")
long and thirty-four inches (34") in diameter.
The above grade discharge is twenty-four inches (24").
4.
General:
(a)
Storage and installation were performed in accordance with manufacturer's instructions.
(b)
No initial alignment prob 1 cms occurred.
(c)
During startup testing excessive vibration readings were obtained at the motor lower and upper bearings of all three (3) pumps - both parallel and perpendicular to the discharge.
Recommended vibration magnitude is 4.5 mils.
Readings ranged from 8.0 to 11.0 mils on the motor lower bearing, and from 8.0 to 24.0 mils on the motor upper bearing.
'i
. r.
~_
(d)
It was determined that the pumps were operating a t resonance g _.,-
(the natural frequency of the unit approximated the oper-
- (<,"
ating speed).
'o (e)
In April 1975 the pump pedestals were replaced wi th a more al rigid design.
The unit natural frequency wa s raised suf-v, ficiently above the operating speed to reduce vibration to acceptable limits.
Specific:
J 2-SW-PSA:
(a)
Startup date:
May 16, 1974.
mi.~
(b)
Motor returned to General Electric for general aAv cleaning and repair on May 20, 1977.
(c)
Pump overhaul on October 3,
1977 which inclaae-replacement of bearings, diffuser, "O"
rine upper and lower shaft, shaft sleeves and casing and impeller wear rings, and shaft couplings.
i149 105
MILLSTONE UNIT NO. 2 (d)
On January 7,
1979 the shaft was straightened and new shaft sleeves, bearings, and casing and impeller wear rings were installed.
(c)
The motor upper bearing was replaced on January 19, 1979.
2-SW-PSB:
(a)
Startup date:
June 8,
1974 (b)
On June 10, 1977 the bearings, shaft sleeves, shaft couplings, and one impeller wear ring were replaced.
This is in addition to the items listed in Item 5 for 2-SW-PSB.
(c)
On January 7,
1979 the shafts were straightened and bearings, shaft sleeves, and impeller and casing wear rings were replaced.
2-SW-PSC:
(a)
Startup date:
June 8,
1974 (b)
On May 17, 1977 the bearings, one coupling, and the casing wear rings were replaced.
This is in addition to the items listed in Item 5 for P-SW-PSC.
(c)
On January 7,
197 9 bearings, shaft sleeves and one wear ring were replaced.
5.
2-SW-PSA:
(a)
On March 20, 1979 cracks were found in the suction bo wl and were determined to be inherent in the original casting.
The affected areas were weld-repaired.
2-SW-PSB:
(a)
Pump overhaul was performed on June 10, 1977 Prior to removal from service, the pump exhibited a 14 mil shaft vibration.
The following items were noted:
(1)
The suction bowl showed signs of accelerated corrosion /crosion in the throat area.
The bowl was replaced with one of stainless steel.
(2)
Severe erosion / corrosion of the diffuser guide vanes was noted.
(3)
The bearing shell in the diffuser casting had spun causing wear in the bote.
Nonmetallic filler material was found in the barc and other sections.of the diffuser.
The bearing set screws were loose.
The bore was reworked to allow proper locking of the bearing.
1149 106
MILLSTONE UNIT NO. 2 (b)
On August 31, 1977 a stainless steel diffuser, impell er and casing wea r rings, and diffuser and suction head bearings were inctalled.
2-SW-PSC (a)
Pump overhaul was performed on Ma y 17, 1977.
Prior to removal from service the pump exhibited a 30 mil shaft vi bra t io n.
The following items were noted:
(1)
The suction bo wl had broken and a large section, including the 1c rer bearing, had fallen into the in ta ke structure bay.
The bowl was replaced with one of stainless steel, as well as the bowl bearing housing.
(2)
The lower end of this pump shaft wa s bad 1y scored.
Three shafts were replaced.
(3)
Severe erosion / corrosion of the diffuser guide vanes was noted.
(b)
On August 31, 1977 a stainless steel diffuser and impeller and casing wear rings were ir kalled.
(c)
The suction bowl wear ring was machined on January 9,
1978.
(d)
The motor thrust bearing was replaced on August 31, 1978.
(c)
On September 5,
1978 the motor was cleaned and the lower guide bearing replaced.
(f)
The motor thrust bearing was replaced on January 26, 1979.
In addition, cracks found on the suction bowl were weld-repaired.
6.
(a)
The longest interval that each pump has been a va il a bl e for operation without corrective maintenance:
2-SW-P5A, approxima tel y October 1977 to January 1979.
2-SW-PSB, approximately June 1977 to January 1979.
2-SW-PSC, approximately May 1977 to January 197 9.
(b)
Identify the number of cycles of operation during this interval.
(c)
The duration of each cycle and the operating mode (s).
1149 107
MILLSTONE UNIT NO. 2
-4 Respon'= to (b) and (c) cannot be obtained.
The cyclic operation of pumps is di cta ted by seasonal changos and plant operating modes.
Deatiled records of pump cycles are not maintained.
(d)
Identify the longest continuous operation at or near rated flow condi tions for cach pump and the status of the pump operability at the and of the run.
Mark No.
Operation (Hours)
Status 2-SW-PSA 6,500 Item 5 2-SW-P5B 2,800 Item 5 2-SW-PSC 8,000 Item 5 i149 108
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