ML19345F752
| ML19345F752 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 01/29/1981 |
| From: | Hoffman D CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| IEB-80-24, NUDOCS 8102190218 | |
| Download: ML19345F752 (8) | |
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7g Consumers Power Company Genere8 offices-212 West Michleen Avenue. Jackson, M6chleen 49201 + (517) 7884550 January 29, 1981
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h Mr James G Keppler fS fib g a 60g,f Office of Inspection and Enforcement H
ko.s.Mbov*" f' Region III 3
US Nuclear Regulatory Commission 3
Q 799 Roosevelt Road Glen Ellyn, IL 60137 b 7 cn DOCKET 50-155 - LICENSE DPR BIG ROCK POINT PLANT -
REVISED RESPONSE TO IE BULLETIN 80-24, PREVENTION OF DA'! AGE DCE TO WATER LEAKAGE INSIDE CONTAINMENT Consumers Power Company letter dated December 23, 1980 provided our initial response to IE Bulletin 80-24 dated November 21, 1980.
NRC review of our submittal resulted in the NRC Resident Inspector, requesting that we issue a revision to our previous response to clarify certain statements as verbally discussed with him.
The following infor=ation is submitted as our complete response (revisions are denoted by lines in the right margin) for Big Rock Point:
Action Reauested 1.
Provide a summary description of all open* cooling water systems present inside containment.
Your description of the cooling water systems must include:
a.
Mode of operation during routine reactor operation and in response to a LOCA.
b.
Source of water and typical chemical content of water.
c.
Materials usd in piping and coolers.
d.
Experience with system leakage.
History and type of repairs to coolers and piping systems (ie, e.
replacement, weld, braze, etc).
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Mr James G Keppler 2
Big Rock Point Plant January 29, 1981 f.
Provisions for isolating portions of the system inside containment in the event of leakage including vulnerability of those isolation provisions to single failure.
g.
Provisions for testing isolation valves in accordance with Appendix J to 10 CFR 50.
4 h.
Instrumentation (pressure, dew point, flow, radiation dercction, etc) and procedures in place to detect leakage.
i.
Provisions to detect radioactive contamination in service water discharge from containment.
Response
1.
The only open cooling water system within containment at Big Rock Point considered to fall within the scope of concern of tre bulletin is the service water system which supplies raw Lake Michigan water to reactor cooling water heat exchangers and reactor enclosure air coolers.
a.
Two 2100 gal / min centrifugal pumps (one running, one in auto standby) supply two reactor cooling water heat exchangers and two reactor building cooling heat exchangers valved in parallel on the service waterside. There is also a locked shut cross-connection to the fire syste= inside contain=ent for emergency supply to the reactor cooling water heat exchangers.
All valves in the system are manual; there-fore, the system will remain in its normal operating configuration in l
respense to a LOCA.
b.
Weekly Lake Michigan water che=ical analyses for the month of November j
1980, considered representative of year-round values, are attached.
c.
Service water piping material is seamless carbon steel, ASTM A-53, Gr A.
deat exchanger tubing is Admiralty metal.
l d.
Experience with system leakage has been limited to routine packing leakage.
l e.
No records of repair to piping or coolers requiring replacement, welding, brazing, etc, within containment were noted.
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f.
All coolers within containment supplied by the service water system are provided with manual isolation valves; single failure criteria was not considered in system design.
It should be noted, however, that the service water system is designed to operate with a higher pressure in the service water system than in the reactor cooling water system, such that any cross-leakage would be into the closed reactor cooling water system with either service water pump running.
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Mr James G Keppler 3
Big Rock Point Plant January 29, 1981 s
g.
Service water isolation valves to the reactor cooling water heat exchangers are not normally leak tested. These are manual valves and would not be accessible for operation during post-LOCA conditions.
h.
The Big Rock Point Plant has a dirty sump and a clean sump at the bottom of the containment sphere, elevation 573'.
Each of these sumps has two automatic pumps which are controlled by float type level switches. This totals four pumps with separate float control.
If both pumps should fail on either sump, the sump woulu fill up and trip a high-level alarm before overflowing to the other sump. The water from both sumps normally flows to the radwaste clean tank, where a rise in tank level would be noted in a short time.
The sump pu=ps are equipped with running time meters, the readings from which are logged each day. These readings are graphed to allow trend analysis for excessive or abnormal pump run times. The discharge isolation valves also have open/ closed indication in the control room.
Each day a sphere leak rate test is performed to record rate of fill of sumps in the sphere. This test was developed to detect possible uncontrolled leakage in the sphere.
There is a humidity recorder in the sphere and one in the control room which reads from several areas of the sphere. These detectors have been very accurate indicators of steam leak conditions.
Another important point is that the top of sumps (573' elevation) is at the same level as the rod drive room floor. Water var:d quickly become visible on the floor if both sumps overflowed.
". ace operations personnel make inspection tours within the sphere each two hours in addition to other routine entries, significant leakage coupled with the failure of all four sump pumps would still be discovered in a short period of time.
There are four containment level indicating lights in the control room which sense water elevations of 574', 579', 587' and 595'.
Because of the indicators and procedures discussed above, it 12 highly unlikely that the water level could reach the first (574') indicator level without being detected. This indication is available, however, to back up the other methods available.
- i. Radioactive ccntamination in service water discharge from containment is monitored by radiation monitor RE-8273. The sample point is upstream of the discharge header which routes water to the discharge canal. The monitor has a recorder and an alarm located in the control room.
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i Mr James G Keppler 4
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Big Rock Point Plant January 29, 1981 Action Requested 2.
For plants with open cooling water systems inside containment take the following actions:
Verify existence or provide redundant means of detecting and promptly a.
alerting control room operators of a significant accumulation of water in containment (including the reactor vessel pit, if present).
b.
Verify existence or provide positive means for control room operators to determine flow from containment sump (s) used to collect and remove water from containment.
c.
Verify or establish at least monthly surveillance procedures, with appropriate opera;ing limitations, to assure plant operators have at least two methods of determining water level in each location where water may accumulate. The surveillance procedures shall assure that at least one method to remove water from each such location is available during power operation.
In the event either the detection or removal systems become inoperable, it is recommended that continued power operation be limited to seven days and added surveillance measures be instituted.
d.
Review leakage detection systems and procedures and provide or verify ability to proeptly detect water leakage in containment, and to isolate the leaking components or system.
Periodi'c containment entry to inspect for leakage should be considered.
Beginning within 10 days of the date of this bulletin, whenever the e.
reactor is operating and until the measures described in "a" through "d" above are implemented, conduct interim surveillance measures. The measures shall include where practical (considering containment j
atmosphere and ALARA considerations) a periodic containment inspection or remote visual surveillance to check for water leakage.
If containment entry is impractical during operation, perform a containment inspection for water leakage at the first plar.t shutdown for any reason subsequent to receipt of this bulletin.
l f.
Establish procedures to notify the NRC of any service water system leaks within containment via a special Licensee Event Report (24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> i
with written report in 14 days) as a degradation of a containment boundary.
Response
i 2.
a.
The redundant means existing to detect and alert the control room l
operators of a significant accumulation of water in containment is l
discussed in "1.h" above.
It is highly unlikely that large amounts of water could accumulate in containment without being detected.
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Mr Jamss G l'eppler 5
Big Rock Point Plant January 29, 1981 b.
The existing means available for control room operators to determine flow from containment sumps is discussed in 1.h above.
c.
Surveillance procedures at Big Rock Point, utilizing multiple means of determining accumulation of water inside containment. are conducted at least daily. Degradation of these ocans to the extent that less than two means of detecting and less than one mean of removing water accumulation inside containment would violate established operating f
procedures and would insure prompt corrective action.
In addition to the above procedural surveillan:..-
normal operating practice includes bihourly operator inspection tours of the containment.
d.
Existing surveillance procedures and detection sysicms have been reviewed. We consider that existing procedures and systems including instructions for identifying / isolating leaking components are sufficient to preclude undetected leakage in containment.
As discussed previously, normal operator duties include periodic containment entry to inspect for leskage.
e.
I. is considered that the interim surveillance procedures required by this paragraph are met in full by existing Big Rock Point systems and procedures. Further action is not considered necessary.
f.
In order to ensure that the new reporting time requirements for service water system leaks inside containment (24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> with written report in 14 days) required by this bulletin are met, they have been added to the revision to plant reporting requirements (Volume IB, Chapter 15) currently undergoing PRC review.
Action Recuested 3.
For plants with closed cooling water systems inside tontainment, provide a summary of experiences with cooling water system leakage into containment.
Response
A review of all completed maintenance orders on closed cooling water systems inside containment was conducted.
Experience.with leakage from such systems 5
has been minimal. The large majority of leakage occurrences has been attributable to packing failures or valve disc seating problems. Only two other leakage occurrences were identified. The first occurrence involved numerous leaks in the heat exchanger (sphere heating and ventilation) area.
This problem has not recurred since February 28, 1965. The second occurrence was due to a sticking float valve supplying makeup water to the heating and cooling system expansion tank on March 7,1974 Manual makeup for this tank is now used which eliminates the potential for recurrence of the same event.
From available documentation, it was not possible to determine the oc1280-0358a-43
Mr Jemas G Ksppler 6
Big Rock Point Plant January 29, 1981 4
=
4 magnitude of leakage, resulting damage or method of discovery for either of 4
l t'nese two occurrences.
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David P Hoffman L
Nuclear Licensing Administrator CC Director, Office of Nuclear Reactor Regulation Director, Office of Inspection and Enforcement NRC Resident Inspector-Big Rock Point i
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CONSUMERS POWER COMPANY Big Rock Point Plant IE Bulletin 80-24 Docket 50-155 License DPR-6 At the request of the Commission and pursuant to the Atomic Energy Act of 1954 and the Energy Reorganization Act of 1974, as amended, and the Commission's Rules and Regulations thereunder, Consumers Power Company submits our re"ised response to IE Bulletin 80-24, dated November 21, 1980 entitled, " Prevention of Damage Due to Water Leakage Inside Containment (October 17, 1980 Indian Point 2 Event)." Consumers Power Company's revised response is dated January 29, 1981 which supersedes our previous response dated December 23, 1980.
CONSUMERS POWER COMPANY
/bd'2'M By R B DeWitt, Vice President, Nuclear Operations Sworn and subscribed to before me this 29th day of January 1981.
/
N's A / ). [(4dhw Linda K Carstens, Notary Public Jackson County, Michigan My cc= mission expires June 10, 1981.
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BIG ROCK POINT NUCLEAR PLANT Weekly Lake Wate-Chemical Analysis Nove.ser 1980 Date 11/5/80 11/14 30 11/20/80 11/26/80 Remarks
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Influent pH 8.2 8.4 8.2 8.2 Turbidity
< 0.1
< 0.1
<C1 0.1 Values in ppm Conductivity 260 230 210 250 Total Hardness 132 126 118 128 Calcium Hardness 84 82 82 86 Magnesium Hardness 48 44 36 42 "P" Alkalinity 4
2 2
4 "M" Alkalinity 94 96 92 98 Chlorides 12 14 11 9
Sulfates 24 NA 4.2 NA Silica 0.6 Total Solids
.4 Iron 0
Effluent pH 8.4 8.4 8.0 8.4 Turbidity
< 0.1
< 0.1
< 0.1 0.1 Conductivity 250 205 250 250 Total Hardness 130 126 122 128 Calcium Hardness 84 80 82 86 Magnesium Hardness 46 46 40 42 "P" Alkalinity 6
2 4
10 "M" Alkalinity 96 94 96 98 Chlorides 11 12 11 10 Sulfates 24 NA 4
NA i
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