ML19351F416
| ML19351F416 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 12/23/1980 |
| 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 8101120574 | |
| Download: ML19351F416 (7) | |
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Mr James G Keppler Office of Inspection and Enforcement Region III US Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, IL 60137 DOCKET 50-155 - LICENSE DPR BIG ROCK POINT PLANT -
RESPONSE TO IE BULLETIN 80-24, PREVENTION OF DA'! AGE DUE TO WATER LEAKAGE INSIDE CONTAINMENT IE Bulletin 80-24 dated November 21, 1980 requested certain information related to inadvertent flooding inside nuclear plant containments.
The following information is submitted as our response for the Big Rock Point Plant:
Action Requested 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 used in piping and coolers.
d.
Experience with system leakage.
e.
History and type of repairs to coolers and piping systems (ie, replacement, weld, braze, etc).
f.
Provisions for isolating portions of the system inside containment in the event of leakage including vulnerability of those isolation provisions to single failure.
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Mr Jcass G K:ppler 2
Big Rock Point Plant December 23, 1980 g.
Provisions for testing isolation valves in accordance with Appendix J to 10 CFR 50.
h.
Instrumentation (pressure, dew point, flow, radiation detection, 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 the bulletin is the service water system which supplies raw Lake Michigan water to reactor cooling water heat exchangers and reactor enclosure air coolers.
a.
TVo 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 system inside containment 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 response to a LOCA.
b.
Weekly Lake Michigan water chemical analyses fcr the month of November 1980, considered representative of year-round values, are attached.
c.
Service water piping material is seamless carbon steel, ASTM A-53, Gr A.
Heat exchanger tubing is Admiralty metal.
d.
Experience with system leakage has been limited to routine packing leakage.
e.
No records of repair to piping or coolers requiring replacement, welding, brazing, etc, within containment were noted.
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.
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 oc1280-0358a-43
Mr Jam;s G Ksppler 3
Big Rock Point Plant December 23, 1980 has two automatic pumps which are controlled by float type level switches. This totals four pumps with separate float control.
If both rumps should fail on either sump, the sump would 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 pumps 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 would quickly become v'isible on t'.te floor if both sumps overflowed. Since 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 is highly unlikely that the water level could reach the first (574') indicator level l
without being detected. This indication is available, however, to l
back up the other methods available.
l
- i. Radioactive contamination 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 j
room.
Action Requested 2.
For plants with open cooling water systems inside containment take the following actions:
a.
Verify existence or provide redundant means of detecting and promptly alerting control room operators of a significant accumulation of water in containment (including the reactor vessel pit, if present),
oc1280-0358a-43
Mr Jam 2s G Kapp1sr 4
Big Rock Point Plant December 23, 1980 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.
Verify or establish at least monthly surveillance procedures, with c.
appropriate operating 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 promptly detect water leakage in containment, and to isolate the leaking components or system. Periodic 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, ccaduct interim surveillance measures. The measures shall include where practical (considering containment 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 leakege at the first plant shutdown for any reason subsequent to receipt of this bulletin.
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 /> with written report in 14 days) as a degradation of a containment boundary.
Response
2.
a.
The redundant means existing to detect and alert the control room operators of a significant accumulation of water in containment is discussed in "1.h" above.
It is highly unlikely that large amounts of water could accumulate in containment without being detected, 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 detcrmining accumulation of water inside containment, are conducted at least daily, including bihourly operator inspection tours of containment. Degradation of these means to the extent that less than two means of detecting and less than one means of removing water accumulation inside containment existed would violate established operating procedures and would insure prompt corrective action, oc1280-0358a-43
Mr Jamas G Kappler 5
Big Rock Point Plant December 23, 1980 3
Therefore, additional limitations on continued plant operation are not considered necessary.
d.
Existing surveillance procedures and detection systems have been reviewed. We consider that existing procedures and systems including instructions for identifying / isolating leaking famponents are suf'icient to preclude undetected leakage in containment. As discussed, present procedures include periodic containment entry to inspect for leakage.
e.
It 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 Requested 3.
For plants with closed cooling water systems inside containment, provide a summary of experiences with cooling water system leakage into containment.
Response
The Big Rock Point experience with cooling water system leakage into containment from closed cooling water systems has been minimal. Normally, the only leakage encountered is valve or pump packing.
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David P Hoffman Nuclear Licensing Administrator CC Director, Office of Nuclear Reactor Regulation Director, Office of Inspection and Enforcement NRC Resident Inspector-Big Rock Point oc1280-0358a-43
CONSUMERS POWER COMPANT 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 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 response is dated December 23, 1980.
CONSUMERS POWER COMPANT By
'I
' / h u,- [ M' R C Youngdahl,fExecutive Vice President Sworn and subscribed to before me this 23rd day of December 1980.
l l F C/ !, ?r l ( [ k W <.5/
Dorothy H prtkus, No'tary Public Jackson County, Michigan My commission expires March 26, 1983.
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i BIG ROCK POINT NUCLEAR PLANT Weekly Lake Water Chemical Analysis November 1980 Date 11/5/80 11/14/80 11/20/80 11/26/80 Remarks Influent pH 8.2 8.4 8.2 8.2 Turbidity
< 0.1
< 0.1
< 0.1.
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 nu1280-0358c-43
-.