ML20098D015

Comment on Proposed NRC Bulletin 95-XX, Potential Plugging of Emergency Core Cooling Suction Strainers by Debris in Boiling Water Reactors & Regulatory Guide DG-1038, Water Sources for Long-Term Recirculation Cooling Following Loca

ML20098D015
Person / Time
Site:	Nine Mile Point
Issue date:	09/29/1995
From:	Sylvia B NIAGARA MOHAWK POWER CORP.
To:	NRC
References
FRN-60FR39021, RTR-REGGD-01.082, RTR-REGGD-1.082, TASK-*****, TASK-RE 60FR39021-00007, 60FR39021-7, NMP1L-0984, NMP1L-984, NUDOCS 9510110050
Download: ML20098D015 (3)

Text

G.M y gWf M V NIAGARA $ Bl/C6 R UMOHAWK ,, @f NIAGARA MOHAWK POWER CORPORATION /NINE MILE POINT, P b. bLGMING, k NY 13093/ TELEPHONE (315) 349-2882 B. Ralph Sylvia Executiva Vice President C -6 ,/'f }. 53

- Nuclear o U: , . September 29,1995 LNMPIL 0984, ]

Rules Review and Directives Branch '

U. S. Nuclear Regulatory Commission Washington, DC 20555-0001 RE: Nine Mile Point Unit 1 Nine Mile Point Unit 2 Docket No. 50-220 Docket No. 50-410 DPR-63 NPF-69

Subject:

Comments on Pmposed NRC Bulletin 95-XX, " Potential Plugging of Emergency Core Cooling Suction Seminen by Debris in Rolling Water l Reactors" and Regulatory Guide DG-1038, " Water Sounesfor Inng-Tenn l Recirculation Cooling Following a Loss-of-Coolant Accident" l Gentlemen:

On July 31,1995, the Nuclear Regulatory Commission published for comment a draft Bulletin, NRC Bulletin 95-XX, " Potential Plugging of Emergency Core Cooling Suction Strainers by Debris in Boiling Water Reactors," and Regulatory Guide DG-1038, " Water Sources for Long-Term Recirculation Cooling Following a Loss-of-Coolant Accident," 60 Fed. Reg. 39021. The proposed Bulletin would request licensees to implement appropriate procedural measures and plant modifications to minimize the potential for clogging of

suppression pool suction strainers of emergency core cooling systems by debris generated during a loss-of-coolant accident. The related draft Regulatory Guide would provide additional technical guidance to licensees. The BWROG has drafted a letter (BWROG-95072) which will provide comments to the Commission concerning the draft Bulletin and

Regulatory Guide. Niagara Mohawk, which has been an active participant in the BWROG

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efforts regarding suction strainer plugging, has reviewed these comments and, in general, is in agreement with the BWROG positions. Niagara Mohawk offers the following comments regarding the draft Bulletin and Regulatory Guide.

Bulletin 95-XX. Page 73 Line 6 Required Response (1), Line 6, requires that a proposed Technical Specification be included in the 180-day report. This requirement should be qualified to read "as appropriate" in that Option 1, large capacity passive strainers, would not require a Technical Specification change. The wording should be similar to that used in Line 12 of Required Response (1).

9510110050 950929 PDR REGGD 01.082 C PDR

.. ; V Page 2 Bulletin 95-XX. Pnee 4.11= 46 Under Option #1, plants with Reflective Metallic Insulation (RMI) in break and target

' locations should be allowed the option of demonstrating that RMI will not cause blockage of

( current' strainers. This evaluation coupled with appropriate housekeeping and control of foreign r.taterial may justify no other modification.

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. BubtIn 95-XX. Pnee 6.14= 44 The draft Bulletin requests that licensees implement the required actions by December 31, 1997. In their draft letter to the Commission, the BWROG requested that the implementation j 4 date of the Bulletin be revised from December 31,1997 to the second refuel outage after issuance of the Bulletin. As indicated above, Niagara Mohawk agrees with this comment and

- provides the following additional concerns regarding the December 31,1997 implementation

~ date.

1. With the existing implementation date of December 31,1997, and the expected c issuance of the Bulletin in late 1995 or early 1996, most licensees would have one or potentially no scheduled refuel outages between the time the 180-day report is submitted and December 31,1997. Those licensees with no outages

} would be forced to shut down to implement any of the proposed modification options. For those licensees with one outage, finishing the required engineering work, fabrication and testing of the selected modification as well as submitting and receiving Commission approval of a Technical Specification amendment (if required) prior to the outage, would be difficult.

. 2. The BWROG proposal to extend the implementation date to the second refuel

, outage following issuance of the Bulletin is consistent with the Commission scheduling requirements associated with other issues that required refuel outage modifications such as Generic Letter (GL) 89-10, " Safety Related Motor Operated Valve Testing and Surveillance." GL 89-10 required l implementation within 5 years or 3 refueling outages, whichever was later.  ;

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3. Unlike many nuclear stations, NMP1 does not have a flanged end connection  !

at the torus suction line. . Therefore, installing a larger capacity suction i strainer on this line (if this option is chosen) will require cutting off the old assembly and welding on a new flanged end to which we can bolt the larger c strainer. Such a modification would require substantial planning and resources i to dewater and decontaminate the torus which could prevent meeting the December 31,1997 implementation date.

4. The required calculation methodologies have not been fully defined or proven.

Requiring utilities to choose or implement modifications prior to their availability (i.e., December 31,1997) could result in an inadequate design or have an adverse affect on ECCS performance and availability.

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..,.A.  !

Page 3 General Comment

.Because of the many open issues on calculational methodologies and the lack of sound test -

data to justify a technical position on debris generation and transport,' we recommend that the final Bulletin and Regulatory Guide not be' issued until a realistic calculational methodology -

is defined by the BWROG through the Utility Resolution Guideline (URG). This comment is consistent with the BWROG position.

Nine Mile Point Unit 1 'was licensed before the various Regulawy Guides and the Standard Review Plan 'were issued. As such, break locations inside the containment were developed and evaluated for a different set of circumstances from that prescribed in this draft Bulletin.

. Before initiating any analytical studies to determine worst case debris generation break L locations, the most appropriate method available for performing these calculations must first be defined.

Very truly yours, B. Ralph Sylvia Executive Vice President - Nuclear BRS/JMT/Imc xc: Regional Administrator, Region I

. Mr. L. B. Marsh, Director, Project Directorate I-l .

l Mr. G. E. Edison, Senior Project Manager, NRR

Mr. B. S. Norris, Senior Resident Inspector  ;

4 Records Management l

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