IR 05000361/1989019

Enforcement Conference Repts 50-361/89-19 & 50-362/89-19 on 890602.Violations Noted.Major Areas Discussed:Concerns Re Inoperability of Emergency Chillers at Facility

ML20246B580
Person / Time
Site:	San Onofre
Issue date:	06/14/1989
From:	Johnson P NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
To:
Shared Package
ML20246B574	List: IR 05000361/1989019 ML20246B570 ML20246B576
References
50-361-89-19-EC, 50-362-89-19, NUDOCS 8907100015
Download: ML20246B580 (6)

Text

_ - _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ - _ . _ _ _ _ -

' '

- .

.

U.S. NUCLEAR REGULATORY COMMISSION

REGION V

Report Ho /89-19, 50-362/89-19 Docket No , 50-362 License No NPF-10, NPF-15

Licensee: Southern California Edison Company P. O. Box 800, 2244 Walnut Grove Avenue Rosemead, California 92770 L ~ Facility Name: San Onofre Units 2 and 3

Meeting Location: Region V Office, Walnut Creek, California Meeting Date: June 2, 1989 Prepared by: F. R. Huey., Senior Resident Inspector Units 1, 2 and 3 Approved By: MAU fl D P. H ohnson, Chief Date Signed Reac Projects Section 3 Meeting Summary Enforcement Conference on June 2, 1989 (Report Nos. 50-361/89-19 and 50-362/89-19)

An enforcement conference was held to discuss concerns relating to inopera-bility of the emergency chillers at San Onofre Nuclear Generating Station Units 2 and )o0015 890622-FDR 0 ADOCK 0500o361 PDC

_

e , ,

,-

- -

s .

DETAILS Meeting Participants Nuclear Regulatory Commission

'

B. H. Faulkenberry, Deputy Regional Administrator R. P. Zimmermcn, Acting Director, Division of Reactor Safety and Projects A. D. Johnson, Enforcement Officer D. F. Kirsch, Chief, Reactor Safety Branch P. H. Johnson, Chief, Reactor Projects Section 3 F. R. Huey, Senior Resident Inspector, San Onofre J. E. Tatum, Resident Inspector, San Onofre Southern California Edison Company C. B. McCarthy, Jr., Vice President and Site Manager K. P. Baskin, Vice President, Nuclear Engineering, Safety and Licensing D. E. Nunn, Manager of Nuclear Engineering and Construction R. W. Krieger, Operations Manager L. D. Brevig, Supervisor, Onsite Nuclear Licensing San Diego Gas and Electric Company R. Lacy, Manager, Nuclear Department Management Discussion An enforcement conference was held on June 2, 1989, at Region V in Walnut Creek, California. The purpose of the conference was to discuss the circumstances and apparent violations associated with inoperability of Unit 2 and 3 emergency chillers units, as described in NRC Inspection .

Report Nos. 50-361/88-35 and 50-362/88-3 Mr. Faulkenberry opeged the conference by explaining the purpose of the enforcement conference and briefly discussed the agenda for the meetin Mr. Zimmerman provided an overview of NRC inspection activities relative to the event, referencing Inspection Report 50-361/88-35 and LER 88-10, applicable tr> Units 2 and 3. Mr. Zimmerman noted that the licensee has had several months to evaluate and reflect on the circumstances of this event, and requested that SCE take advantage of the enforcement conference to communicate any additional information or conclusions on this matter to the NR !

Mr. Huey provided the following summary of the inspection details:

• On April 22, 1938, the NRC inspector observed that there was no visible Freon level in the cooler sight glass for emergency chiller ME-336. The inspector also noted that a deficiency tag dated April 2, 1988 identified that refrigerant level was low in chiller ME-336. The inspector discussed this observation with the Shift i I

!

, _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - _ _ ___ _____-- _ __ _ _ _ _

. -

.

. - 2

%

/

[

Superintendent (SS) and questioned the operability of ME-336'. . The s SS stated that there were no specific criteria in the operating instructions. relative to this deficiency and that additional-evaluation would have to be performe * On May.5,1988, (lacking any clear guidance on required Freon level

,

>

from the station technical support organization) the Operations Manager provided preliminary guidance that Freon level must be visible in the sight glass in order for the emergency chiller to be ,

considered operable. On May 6, based on this new guidance, ME-336 -

j

<

was declared inoperabl * On May 6, following the declaration of chiller ME-336 -

inoperability, the emergency chiller unit associated with the other train (ME-335) was. started and tripped due to low refrigerant temperature. This condition was the result of low Freon level, in conjunction with low' component cooling water temperature. When unit ME-335 was started, it contained approximately 1 1/2" of Freon l in the cooler sight glass. Accordingly, both emergency chiller units were declared inoperable, and Technical Specification (TS)

'

Action Statement 3.0.3 was entered for.approximately 3 1/2 hour After Freon was added to unit ME-336, it was declared operabl * LER 361/88-10, issued on June 6, 1988, discussed the details of this event (TS 3.0.3 entry). The NRC expressed a concern that the LER was inadequate in that the design basis for the emergency chiller units was not discussed and the safety significance of the event was not define * SCE issued Revision 1 to LER 2-88-10 on October 14, 1988. The revised LER defined the design basis for the emergency chiller units, and stated that both trains of emergency chillers would

'

probably have tripped on low refrigerant temperature during a four-day period between May 2 and 6, 1988. The NRC also concluded, based on the criteria' established in the LER, that the Freon level which was observed by the inspector on April 2P, 1988, and which remained uncorrected until May 6, 1988 was below the level required for ME-336 to remove its design heat load of 320 Tons. The revised LER also recognized that Freon requirements for the emergency ,

chillers had not been adequately defined, and stated that i corrective actions to address the inspector's observation on April 22 had been slow. The safety significance established by the revised LER concluded that the emergency chillers may not have been able to mitigate the consequences of an even * Additional followup inspection identified that previous examples of low Freon level existed, as well as some instances in which chillers did not function properly as a result of apparently improper Freon charge. The inspectors also identified other weaknesses in the licensee's surveillance requirements for the emergency chillers, and noted that the revised LER did not adequately address the generic implication of the chiller problems for other safety related equipment.

L __ . _ _ _ _ _ _ _ _ _ _ _

_ _ _ _ - _ _ _ _ ____ _ _ _ - _ _ _ _ _ __ ____

t i g .i : ,

" ,

,. ,

.' . 3 Following Mr. Huey's summary of the inspection details, Mr. P. Johnson provided the following summary of the apparent violations of regulatory requirements:

• The licensee's corrective action to address the low Freon level in ME-336 on April 2, 1988, was inadequate, untimely, and in apparent violation.of 10CFR50 Apperidix B, Criterion XVI. As a result,

.

'

chiller operability as required by the Technical Specifications was not assured; one chiller (ME-336) was inoperable for 12 days and both chillers (ME-335 and ME-336) were inoperable simultaneously for four day * The licensee did not translate design requirements'(e.g., Freon sight glass level) for the emergency chiller system into appropriate procedures and instructions, in violation of 10CFR50 Appendix B, Criterion II !

Following the discussions by Mr. Huey and Mr. Johnson, Mr. Zimmerman requested that SCE discuss any additional information or conclusions which they had reached involving the emergency chiller issue, In particular, he requested that SCE address the lack of timely action in response to the original NRC concer Mr. Krieger agreed that corrective actions should have been more aggressive and timely, but presented the following information to at least partially explain the delay:

• Operating instructions did not contain guidance relative to requirnd Freon level in the emergency chiller cooler sight glas * Operations personnel had established a mindset that no Freon level was required in the cooler sight glass. He noted that the emergency chillers had been operated in the past when no Freon level was visible in the cooler sight glass, and the chillers had appeared to function satisfactorily. He also stated that chiller

. maintenance history did not indicate that Freon level was a serious Concern.

,

• Maintenance and technical personnel were not cognizant of any ,

'

specific requirements relative to Freon level requirements and the {

vendor manual did not specify any requirement '

• The vendor did not have any specific information relative to sight

. glass level requirement * Discussion and evaluation of this problem occurred from April 22 l

through April 28. Although a specific requirement for sight glass Freon level could not be found, the Operations Manager established preliminary guidance on April 28 and procedure revisions were completed on May * Although discussions continued with the vendor, the vendor was not of much assistance. The station technical organization performed a J

- _ _ _ _ - _ _ _ _ _ _ _ _ _ _ - _ _ _ _ _ _ - _ _

. _ _ - . _- _ _ _ _ _ . _ _ _ _ _ _ . _ _ - _ _ _ _ _ - _ - _ . _ _ _ _ _ _ _

,

l l4 .' W .

-

,

, _- 4

.

detailed evaluation of the Freon requirements for the emergency chiller units', and defined a correlation between Freon level in the cooler and component cooling water temperature. The results of

this evaluation have been reflected in procedure requirements.

,

Mr. Krieger stated that the following actions have been taken to l evaluate the applicability of this problem to'other systems and-

. components:

• All other safety related heating, ventilating, and air conditioning (HVAC) systems were evaluated. The emergency chillers were the only ones with a Freon cycle, and this specific problem did not exist on any other safety related equipmen * The surveillance requirements for other safety related standby systems were evaluated,.and inspection programs have been estab-lished for critical standby systems (those safety related and non-safety related systems that can cause a reactor trip).

. Mr. Zimmerman stated that the operators' mindset, which considered no visible Freon level in the cooler sight glass to be acceptable, should not have existed. Mr. Krieger agreed and stated that this point had been discussed with the operator Mr. Zimmerman asked why the vendor was not more helpful in resolving this problem. Mr. Nunn responded by stating that the chiller units are typically used for commercial applications, and the vendor did not have specific requirements for Freon level in the cooler sight glass. In fact, the sight glass typically is not supplied with the cooler and was an optional' piece of equipment which was ordered by SC Mr. Zimmerman asked if the proper level of management had been involved, both in the vendor's organization and in the licensee's organizatio Mr. Nunn stated that more timely management involvement would have been appropriate in this case, and that this problem is similar to others that resulted in the engineering reorganizatio Mr. Faulkenberry asked what would happen today if a similar situation were to occur. Mr. Baskin responded that it would depend on the system involved. Certain systems are further along in the design basis review than others, and the complete review of all systems will not be completed for approximately five years. Mr. Nunn stated that as a part of the corrective actions taken in response to the SSFI findings, a training program was established for system engineers. Mr. Baskin also emphasized that consolidation of the design organization in one location closer to the site will make it easier for the engineers to keep in

, touch with their system Mr. Zimmerman stated that he felt comfortable with the licensee's long term resolution of the problem, but was uncomfortable with short term re:,olution. He asked whether appropriate operations, maintenance and technical personnel have been trained relative to this problem and asked the licensee to describe what has been done to encourage plant operators

_ _ _ - _ _ _ _ -

w .

x c lflr '*f,

'

,

M '

'

c '

.. .

lp to[identifysimilarproblemswhereinacceptancecriteriado-notexist

,

for. parameters (e.g., level, temperature, or pressure) associated with

,

important plant equipment. Mr. Krieger stated that training of appro-

,, :priate personnel has.been completed relative to this problem, but that

'3 . operators have not.been specifically asked to'come forward with

.# P .g ' problems. .Mr. Nunn noted that such an ? approach would probably be of 4 marginal benefit, in that the anticipated response would be a.large

. input. of perceived, problems of a noncritical nature. . Messrs. Zimmerman L 'and Kirsch noted that it may be warranted for the plant engineering <

'

organization to dedicate additional effort to; work with plant operators,

~

.as.part.of a shorter term corrective action program, in ordcr to

- '

. identify any other problem areas that might exis O In this; regard, Mr. Huey noted that cognizant engineering and operation personnel.could perform a dedicated joint review of the adequacy of:

,

operator rounds sheets, in the context of lessons learned from the c chiller unit problems.: Mr.' Huey also noted that additional' actions appeared to be warranted with regard to specific highlighting of lessons :

. learned from the emergency chillers on the checklists being utilized as s part of.the current design basis document review proces .

+

.

.

• - Mr.'Faulkenberry noted that a number of recent plant problems had occurred that~may share some similarities with the root'cause of the f +

emergency chiller problem:

"

• Wide range steam generator level discrepancy (Unit 1)

• Inadequate surveillance testing of the reactor trip breaker shunt

. trip device (Unit 1)

• Imp oper ring setting of the steam generator safety valves (Units 2

&3 i

• Nuclear instrumentation noise problems (Unit 1)

Mr. Baskin replied that the first three examples were design engineering deficiencies in that quality, knowledge and implementation of design requirements were inadequate. These fall within the scope of the design basis document review program, which is being performed over the next'

five years. The last item was an example of having the wrong engineering people on shift such that the oprators did not get adequate engineering support. This problem should not happen again. Mr. Baskin

.again emphasized the importance of the. engineering reorganization in providing some resolution of these problem Mr. A. Johnson asked whether the licensee representatives had any questions regarding the NRC enforcement policy. Mr. Baskin stated that

, the licensee understood the enforcement policy and had no question In closing the conference, Mr. Faulkenberry requested that the licensee be prepared to address any additional lessons that have been learned in ,

..this regard, along with actions being implemented to improve perform- '

.ance, during the upcoming June 27 management meeting at San Onofr '

_ _ _ - _ _____-- __ _____ -